diff --git a/api/commands.py b/api/commands.py
index e24b1826ee..20ce22a6c7 100644
--- a/api/commands.py
+++ b/api/commands.py
@@ -35,7 +35,7 @@ from libs.rsa import generate_key_pair
 from models import Tenant
 from models.dataset import Dataset, DatasetCollectionBinding, DatasetMetadata, DatasetMetadataBinding, DocumentSegment
 from models.dataset import Document as DatasetDocument
-from models.model import Account, App, AppAnnotationSetting, AppMode, Conversation, MessageAnnotation, UploadFile
+from models.model import App, AppAnnotationSetting, AppMode, Conversation, MessageAnnotation, UploadFile
 from models.oauth import DatasourceOauthParamConfig, DatasourceProvider
 from models.provider import Provider, ProviderModel
 from models.provider_ids import DatasourceProviderID, ToolProviderID
@@ -64,8 +64,10 @@ def reset_password(email, new_password, password_confirm):
     if str(new_password).strip() != str(password_confirm).strip():
         click.echo(click.style("Passwords do not match.", fg="red"))
         return
+    normalized_email = email.strip().lower()
+
     with sessionmaker(db.engine, expire_on_commit=False).begin() as session:
-        account = session.query(Account).where(Account.email == email).one_or_none()
+        account = AccountService.get_account_by_email_with_case_fallback(email.strip(), session=session)
 
         if not account:
             click.echo(click.style(f"Account not found for email: {email}", fg="red"))
@@ -86,7 +88,7 @@ def reset_password(email, new_password, password_confirm):
         base64_password_hashed = base64.b64encode(password_hashed).decode()
         account.password = base64_password_hashed
         account.password_salt = base64_salt
-        AccountService.reset_login_error_rate_limit(email)
+        AccountService.reset_login_error_rate_limit(normalized_email)
         click.echo(click.style("Password reset successfully.", fg="green"))
 
 
@@ -102,20 +104,22 @@ def reset_email(email, new_email, email_confirm):
     if str(new_email).strip() != str(email_confirm).strip():
         click.echo(click.style("New emails do not match.", fg="red"))
         return
+    normalized_new_email = new_email.strip().lower()
+
     with sessionmaker(db.engine, expire_on_commit=False).begin() as session:
-        account = session.query(Account).where(Account.email == email).one_or_none()
+        account = AccountService.get_account_by_email_with_case_fallback(email.strip(), session=session)
 
         if not account:
             click.echo(click.style(f"Account not found for email: {email}", fg="red"))
             return
 
         try:
-            email_validate(new_email)
+            email_validate(normalized_new_email)
         except:
             click.echo(click.style(f"Invalid email: {new_email}", fg="red"))
             return
 
-        account.email = new_email
+        account.email = normalized_new_email
         click.echo(click.style("Email updated successfully.", fg="green"))
 
 
@@ -660,7 +664,7 @@ def create_tenant(email: str, language: str | None = None, name: str | None = No
         return
 
     # Create account
-    email = email.strip()
+    email = email.strip().lower()
 
     if "@" not in email:
         click.echo(click.style("Invalid email address.", fg="red"))
diff --git a/api/controllers/console/auth/activate.py b/api/controllers/console/auth/activate.py
index fe70d930fb..cfc673880c 100644
--- a/api/controllers/console/auth/activate.py
+++ b/api/controllers/console/auth/activate.py
@@ -63,10 +63,9 @@ class ActivateCheckApi(Resource):
         args = ActivateCheckQuery.model_validate(request.args.to_dict(flat=True))  # type: ignore
 
         workspaceId = args.workspace_id
-        reg_email = args.email
         token = args.token
 
-        invitation = RegisterService.get_invitation_if_token_valid(workspaceId, reg_email, token)
+        invitation = RegisterService.get_invitation_with_case_fallback(workspaceId, args.email, token)
         if invitation:
             data = invitation.get("data", {})
             tenant = invitation.get("tenant", None)
@@ -100,11 +99,12 @@ class ActivateApi(Resource):
     def post(self):
         args = ActivatePayload.model_validate(console_ns.payload)
 
-        invitation = RegisterService.get_invitation_if_token_valid(args.workspace_id, args.email, args.token)
+        normalized_request_email = args.email.lower() if args.email else None
+        invitation = RegisterService.get_invitation_with_case_fallback(args.workspace_id, args.email, args.token)
         if invitation is None:
             raise AlreadyActivateError()
 
-        RegisterService.revoke_token(args.workspace_id, args.email, args.token)
+        RegisterService.revoke_token(args.workspace_id, normalized_request_email, args.token)
 
         account = invitation["account"]
         account.name = args.name
diff --git a/api/controllers/console/auth/email_register.py b/api/controllers/console/auth/email_register.py
index fa082c735d..c2a95ddad2 100644
--- a/api/controllers/console/auth/email_register.py
+++ b/api/controllers/console/auth/email_register.py
@@ -1,7 +1,6 @@
 from flask import request
 from flask_restx import Resource
 from pydantic import BaseModel, Field, field_validator
-from sqlalchemy import select
 from sqlalchemy.orm import Session
 
 from configs import dify_config
@@ -62,6 +61,7 @@ class EmailRegisterSendEmailApi(Resource):
     @email_register_enabled
     def post(self):
         args = EmailRegisterSendPayload.model_validate(console_ns.payload)
+        normalized_email = args.email.lower()
 
         ip_address = extract_remote_ip(request)
         if AccountService.is_email_send_ip_limit(ip_address):
@@ -70,13 +70,12 @@ class EmailRegisterSendEmailApi(Resource):
         if args.language in languages:
             language = args.language
 
-        if dify_config.BILLING_ENABLED and BillingService.is_email_in_freeze(args.email):
+        if dify_config.BILLING_ENABLED and BillingService.is_email_in_freeze(normalized_email):
             raise AccountInFreezeError()
 
         with Session(db.engine) as session:
-            account = session.execute(select(Account).filter_by(email=args.email)).scalar_one_or_none()
-        token = None
-        token = AccountService.send_email_register_email(email=args.email, account=account, language=language)
+            account = AccountService.get_account_by_email_with_case_fallback(args.email, session=session)
+        token = AccountService.send_email_register_email(email=normalized_email, account=account, language=language)
         return {"result": "success", "data": token}
 
 
@@ -88,9 +87,9 @@ class EmailRegisterCheckApi(Resource):
     def post(self):
         args = EmailRegisterValidityPayload.model_validate(console_ns.payload)
 
-        user_email = args.email
+        user_email = args.email.lower()
 
-        is_email_register_error_rate_limit = AccountService.is_email_register_error_rate_limit(args.email)
+        is_email_register_error_rate_limit = AccountService.is_email_register_error_rate_limit(user_email)
         if is_email_register_error_rate_limit:
             raise EmailRegisterLimitError()
 
@@ -98,11 +97,14 @@ class EmailRegisterCheckApi(Resource):
         if token_data is None:
             raise InvalidTokenError()
 
-        if user_email != token_data.get("email"):
+        token_email = token_data.get("email")
+        normalized_token_email = token_email.lower() if isinstance(token_email, str) else token_email
+
+        if user_email != normalized_token_email:
             raise InvalidEmailError()
 
         if args.code != token_data.get("code"):
-            AccountService.add_email_register_error_rate_limit(args.email)
+            AccountService.add_email_register_error_rate_limit(user_email)
             raise EmailCodeError()
 
         # Verified, revoke the first token
@@ -113,8 +115,8 @@ class EmailRegisterCheckApi(Resource):
             user_email, code=args.code, additional_data={"phase": "register"}
         )
 
-        AccountService.reset_email_register_error_rate_limit(args.email)
-        return {"is_valid": True, "email": token_data.get("email"), "token": new_token}
+        AccountService.reset_email_register_error_rate_limit(user_email)
+        return {"is_valid": True, "email": normalized_token_email, "token": new_token}
 
 
 @console_ns.route("/email-register")
@@ -141,22 +143,23 @@ class EmailRegisterResetApi(Resource):
         AccountService.revoke_email_register_token(args.token)
 
         email = register_data.get("email", "")
+        normalized_email = email.lower()
 
         with Session(db.engine) as session:
-            account = session.execute(select(Account).filter_by(email=email)).scalar_one_or_none()
+            account = AccountService.get_account_by_email_with_case_fallback(email, session=session)
 
             if account:
                 raise EmailAlreadyInUseError()
             else:
-                account = self._create_new_account(email, args.password_confirm)
+                account = self._create_new_account(normalized_email, args.password_confirm)
                 if not account:
                     raise AccountNotFoundError()
                 token_pair = AccountService.login(account=account, ip_address=extract_remote_ip(request))
-                AccountService.reset_login_error_rate_limit(email)
+                AccountService.reset_login_error_rate_limit(normalized_email)
 
         return {"result": "success", "data": token_pair.model_dump()}
 
-    def _create_new_account(self, email, password) -> Account | None:
+    def _create_new_account(self, email: str, password: str) -> Account | None:
         # Create new account if allowed
         account = None
         try:
diff --git a/api/controllers/console/auth/forgot_password.py b/api/controllers/console/auth/forgot_password.py
index 661f591182..394f205d93 100644
--- a/api/controllers/console/auth/forgot_password.py
+++ b/api/controllers/console/auth/forgot_password.py
@@ -4,7 +4,6 @@ import secrets
 from flask import request
 from flask_restx import Resource, fields
 from pydantic import BaseModel, Field, field_validator
-from sqlalchemy import select
 from sqlalchemy.orm import Session
 
 from controllers.console import console_ns
@@ -21,7 +20,6 @@ from events.tenant_event import tenant_was_created
 from extensions.ext_database import db
 from libs.helper import EmailStr, extract_remote_ip
 from libs.password import hash_password, valid_password
-from models import Account
 from services.account_service import AccountService, TenantService
 from services.feature_service import FeatureService
 
@@ -76,6 +74,7 @@ class ForgotPasswordSendEmailApi(Resource):
     @email_password_login_enabled
     def post(self):
         args = ForgotPasswordSendPayload.model_validate(console_ns.payload)
+        normalized_email = args.email.lower()
 
         ip_address = extract_remote_ip(request)
         if AccountService.is_email_send_ip_limit(ip_address):
@@ -87,11 +86,11 @@ class ForgotPasswordSendEmailApi(Resource):
             language = "en-US"
 
         with Session(db.engine) as session:
-            account = session.execute(select(Account).filter_by(email=args.email)).scalar_one_or_none()
+            account = AccountService.get_account_by_email_with_case_fallback(args.email, session=session)
 
         token = AccountService.send_reset_password_email(
             account=account,
-            email=args.email,
+            email=normalized_email,
             language=language,
             is_allow_register=FeatureService.get_system_features().is_allow_register,
         )
@@ -122,9 +121,9 @@ class ForgotPasswordCheckApi(Resource):
     def post(self):
         args = ForgotPasswordCheckPayload.model_validate(console_ns.payload)
 
-        user_email = args.email
+        user_email = args.email.lower()
 
-        is_forgot_password_error_rate_limit = AccountService.is_forgot_password_error_rate_limit(args.email)
+        is_forgot_password_error_rate_limit = AccountService.is_forgot_password_error_rate_limit(user_email)
         if is_forgot_password_error_rate_limit:
             raise EmailPasswordResetLimitError()
 
@@ -132,11 +131,16 @@ class ForgotPasswordCheckApi(Resource):
         if token_data is None:
             raise InvalidTokenError()
 
-        if user_email != token_data.get("email"):
+        token_email = token_data.get("email")
+        if not isinstance(token_email, str):
+            raise InvalidEmailError()
+        normalized_token_email = token_email.lower()
+
+        if user_email != normalized_token_email:
             raise InvalidEmailError()
 
         if args.code != token_data.get("code"):
-            AccountService.add_forgot_password_error_rate_limit(args.email)
+            AccountService.add_forgot_password_error_rate_limit(user_email)
             raise EmailCodeError()
 
         # Verified, revoke the first token
@@ -144,11 +148,11 @@ class ForgotPasswordCheckApi(Resource):
 
         # Refresh token data by generating a new token
         _, new_token = AccountService.generate_reset_password_token(
-            user_email, code=args.code, additional_data={"phase": "reset"}
+            token_email, code=args.code, additional_data={"phase": "reset"}
         )
 
-        AccountService.reset_forgot_password_error_rate_limit(args.email)
-        return {"is_valid": True, "email": token_data.get("email"), "token": new_token}
+        AccountService.reset_forgot_password_error_rate_limit(user_email)
+        return {"is_valid": True, "email": normalized_token_email, "token": new_token}
 
 
 @console_ns.route("/forgot-password/resets")
@@ -187,9 +191,8 @@ class ForgotPasswordResetApi(Resource):
         password_hashed = hash_password(args.new_password, salt)
 
         email = reset_data.get("email", "")
-
         with Session(db.engine) as session:
-            account = session.execute(select(Account).filter_by(email=email)).scalar_one_or_none()
+            account = AccountService.get_account_by_email_with_case_fallback(email, session=session)
 
             if account:
                 self._update_existing_account(account, password_hashed, salt, session)
diff --git a/api/controllers/console/auth/login.py b/api/controllers/console/auth/login.py
index 4a52bf8abe..400df138b8 100644
--- a/api/controllers/console/auth/login.py
+++ b/api/controllers/console/auth/login.py
@@ -90,32 +90,38 @@ class LoginApi(Resource):
     def post(self):
         """Authenticate user and login."""
         args = LoginPayload.model_validate(console_ns.payload)
+        request_email = args.email
+        normalized_email = request_email.lower()
 
-        if dify_config.BILLING_ENABLED and BillingService.is_email_in_freeze(args.email):
+        if dify_config.BILLING_ENABLED and BillingService.is_email_in_freeze(normalized_email):
             raise AccountInFreezeError()
 
-        is_login_error_rate_limit = AccountService.is_login_error_rate_limit(args.email)
+        is_login_error_rate_limit = AccountService.is_login_error_rate_limit(normalized_email)
         if is_login_error_rate_limit:
             raise EmailPasswordLoginLimitError()
 
+        invite_token = args.invite_token
         invitation_data: dict[str, Any] | None = None
-        if args.invite_token:
-            invitation_data = RegisterService.get_invitation_if_token_valid(None, args.email, args.invite_token)
+        if invite_token:
+            invitation_data = RegisterService.get_invitation_with_case_fallback(None, request_email, invite_token)
+            if invitation_data is None:
+                invite_token = None
 
         try:
             if invitation_data:
                 data = invitation_data.get("data", {})
                 invitee_email = data.get("email") if data else None
-                if invitee_email != args.email:
+                invitee_email_normalized = invitee_email.lower() if isinstance(invitee_email, str) else invitee_email
+                if invitee_email_normalized != normalized_email:
                     raise InvalidEmailError()
-                account = AccountService.authenticate(args.email, args.password, args.invite_token)
-            else:
-                account = AccountService.authenticate(args.email, args.password)
+            account = _authenticate_account_with_case_fallback(
+                request_email, normalized_email, args.password, invite_token
+            )
         except services.errors.account.AccountLoginError:
             raise AccountBannedError()
-        except services.errors.account.AccountPasswordError:
-            AccountService.add_login_error_rate_limit(args.email)
-            raise AuthenticationFailedError()
+        except services.errors.account.AccountPasswordError as exc:
+            AccountService.add_login_error_rate_limit(normalized_email)
+            raise AuthenticationFailedError() from exc
         # SELF_HOSTED only have one workspace
         tenants = TenantService.get_join_tenants(account)
         if len(tenants) == 0:
@@ -130,7 +136,7 @@ class LoginApi(Resource):
                 }
 
         token_pair = AccountService.login(account=account, ip_address=extract_remote_ip(request))
-        AccountService.reset_login_error_rate_limit(args.email)
+        AccountService.reset_login_error_rate_limit(normalized_email)
 
         # Create response with cookies instead of returning tokens in body
         response = make_response({"result": "success"})
@@ -170,18 +176,19 @@ class ResetPasswordSendEmailApi(Resource):
     @console_ns.expect(console_ns.models[EmailPayload.__name__])
     def post(self):
         args = EmailPayload.model_validate(console_ns.payload)
+        normalized_email = args.email.lower()
 
         if args.language is not None and args.language == "zh-Hans":
             language = "zh-Hans"
         else:
             language = "en-US"
         try:
-            account = AccountService.get_user_through_email(args.email)
+            account = _get_account_with_case_fallback(args.email)
         except AccountRegisterError:
             raise AccountInFreezeError()
 
         token = AccountService.send_reset_password_email(
-            email=args.email,
+            email=normalized_email,
             account=account,
             language=language,
             is_allow_register=FeatureService.get_system_features().is_allow_register,
@@ -196,6 +203,7 @@ class EmailCodeLoginSendEmailApi(Resource):
     @console_ns.expect(console_ns.models[EmailPayload.__name__])
     def post(self):
         args = EmailPayload.model_validate(console_ns.payload)
+        normalized_email = args.email.lower()
 
         ip_address = extract_remote_ip(request)
         if AccountService.is_email_send_ip_limit(ip_address):
@@ -206,13 +214,13 @@ class EmailCodeLoginSendEmailApi(Resource):
         else:
             language = "en-US"
         try:
-            account = AccountService.get_user_through_email(args.email)
+            account = _get_account_with_case_fallback(args.email)
         except AccountRegisterError:
             raise AccountInFreezeError()
 
         if account is None:
             if FeatureService.get_system_features().is_allow_register:
-                token = AccountService.send_email_code_login_email(email=args.email, language=language)
+                token = AccountService.send_email_code_login_email(email=normalized_email, language=language)
             else:
                 raise AccountNotFound()
         else:
@@ -229,14 +237,17 @@ class EmailCodeLoginApi(Resource):
     def post(self):
         args = EmailCodeLoginPayload.model_validate(console_ns.payload)
 
-        user_email = args.email
+        original_email = args.email
+        user_email = original_email.lower()
         language = args.language
 
         token_data = AccountService.get_email_code_login_data(args.token)
         if token_data is None:
             raise InvalidTokenError()
 
-        if token_data["email"] != args.email:
+        token_email = token_data.get("email")
+        normalized_token_email = token_email.lower() if isinstance(token_email, str) else token_email
+        if normalized_token_email != user_email:
             raise InvalidEmailError()
 
         if token_data["code"] != args.code:
@@ -244,7 +255,7 @@ class EmailCodeLoginApi(Resource):
 
         AccountService.revoke_email_code_login_token(args.token)
         try:
-            account = AccountService.get_user_through_email(user_email)
+            account = _get_account_with_case_fallback(original_email)
         except AccountRegisterError:
             raise AccountInFreezeError()
         if account:
@@ -275,7 +286,7 @@ class EmailCodeLoginApi(Resource):
             except WorkspacesLimitExceededError:
                 raise WorkspacesLimitExceeded()
         token_pair = AccountService.login(account, ip_address=extract_remote_ip(request))
-        AccountService.reset_login_error_rate_limit(args.email)
+        AccountService.reset_login_error_rate_limit(user_email)
 
         # Create response with cookies instead of returning tokens in body
         response = make_response({"result": "success"})
@@ -309,3 +320,22 @@ class RefreshTokenApi(Resource):
             return response
         except Exception as e:
             return {"result": "fail", "message": str(e)}, 401
+
+
+def _get_account_with_case_fallback(email: str):
+    account = AccountService.get_user_through_email(email)
+    if account or email == email.lower():
+        return account
+
+    return AccountService.get_user_through_email(email.lower())
+
+
+def _authenticate_account_with_case_fallback(
+    original_email: str, normalized_email: str, password: str, invite_token: str | None
+):
+    try:
+        return AccountService.authenticate(original_email, password, invite_token)
+    except services.errors.account.AccountPasswordError:
+        if original_email == normalized_email:
+            raise
+        return AccountService.authenticate(normalized_email, password, invite_token)
diff --git a/api/controllers/console/auth/oauth.py b/api/controllers/console/auth/oauth.py
index c20e83d36f..112e152432 100644
--- a/api/controllers/console/auth/oauth.py
+++ b/api/controllers/console/auth/oauth.py
@@ -3,7 +3,6 @@ import logging
 import httpx
 from flask import current_app, redirect, request
 from flask_restx import Resource
-from sqlalchemy import select
 from sqlalchemy.orm import Session
 from werkzeug.exceptions import Unauthorized
 
@@ -118,7 +117,10 @@ class OAuthCallback(Resource):
             invitation = RegisterService.get_invitation_by_token(token=invite_token)
             if invitation:
                 invitation_email = invitation.get("email", None)
-                if invitation_email != user_info.email:
+                invitation_email_normalized = (
+                    invitation_email.lower() if isinstance(invitation_email, str) else invitation_email
+                )
+                if invitation_email_normalized != user_info.email.lower():
                     return redirect(f"{dify_config.CONSOLE_WEB_URL}/signin?message=Invalid invitation token.")
 
             return redirect(f"{dify_config.CONSOLE_WEB_URL}/signin/invite-settings?invite_token={invite_token}")
@@ -175,7 +177,7 @@ def _get_account_by_openid_or_email(provider: str, user_info: OAuthUserInfo) ->
 
     if not account:
         with Session(db.engine) as session:
-            account = session.execute(select(Account).filter_by(email=user_info.email)).scalar_one_or_none()
+            account = AccountService.get_account_by_email_with_case_fallback(user_info.email, session=session)
 
     return account
 
@@ -197,9 +199,10 @@ def _generate_account(provider: str, user_info: OAuthUserInfo) -> tuple[Account,
                 tenant_was_created.send(new_tenant)
 
     if not account:
+        normalized_email = user_info.email.lower()
         oauth_new_user = True
         if not FeatureService.get_system_features().is_allow_register:
-            if dify_config.BILLING_ENABLED and BillingService.is_email_in_freeze(user_info.email):
+            if dify_config.BILLING_ENABLED and BillingService.is_email_in_freeze(normalized_email):
                 raise AccountRegisterError(
                     description=(
                         "This email account has been deleted within the past "
@@ -210,7 +213,11 @@ def _generate_account(provider: str, user_info: OAuthUserInfo) -> tuple[Account,
                 raise AccountRegisterError(description=("Invalid email or password"))
         account_name = user_info.name or "Dify"
         account = RegisterService.register(
-            email=user_info.email, name=account_name, password=None, open_id=user_info.id, provider=provider
+            email=normalized_email,
+            name=account_name,
+            password=None,
+            open_id=user_info.id,
+            provider=provider,
         )
 
         # Set interface language
diff --git a/api/controllers/console/setup.py b/api/controllers/console/setup.py
index 7fa02ae280..ed22ef045d 100644
--- a/api/controllers/console/setup.py
+++ b/api/controllers/console/setup.py
@@ -84,10 +84,11 @@ class SetupApi(Resource):
             raise NotInitValidateError()
 
         args = SetupRequestPayload.model_validate(console_ns.payload)
+        normalized_email = args.email.lower()
 
         # setup
         RegisterService.setup(
-            email=args.email,
+            email=normalized_email,
             name=args.name,
             password=args.password,
             ip_address=extract_remote_ip(request),
diff --git a/api/controllers/console/workspace/account.py b/api/controllers/console/workspace/account.py
index 03ad0f423b..527aabbc3d 100644
--- a/api/controllers/console/workspace/account.py
+++ b/api/controllers/console/workspace/account.py
@@ -41,7 +41,7 @@ from fields.member_fields import account_fields
 from libs.datetime_utils import naive_utc_now
 from libs.helper import EmailStr, TimestampField, extract_remote_ip, timezone
 from libs.login import current_account_with_tenant, login_required
-from models import Account, AccountIntegrate, InvitationCode
+from models import AccountIntegrate, InvitationCode
 from services.account_service import AccountService
 from services.billing_service import BillingService
 from services.errors.account import CurrentPasswordIncorrectError as ServiceCurrentPasswordIncorrectError
@@ -536,7 +536,8 @@ class ChangeEmailSendEmailApi(Resource):
         else:
             language = "en-US"
         account = None
-        user_email = args.email
+        user_email = None
+        email_for_sending = args.email.lower()
         if args.phase is not None and args.phase == "new_email":
             if args.token is None:
                 raise InvalidTokenError()
@@ -546,16 +547,24 @@ class ChangeEmailSendEmailApi(Resource):
                 raise InvalidTokenError()
             user_email = reset_data.get("email", "")
 
-            if user_email != current_user.email:
+            if user_email.lower() != current_user.email.lower():
                 raise InvalidEmailError()
+
+            user_email = current_user.email
         else:
             with Session(db.engine) as session:
-                account = session.execute(select(Account).filter_by(email=args.email)).scalar_one_or_none()
+                account = AccountService.get_account_by_email_with_case_fallback(args.email, session=session)
             if account is None:
                 raise AccountNotFound()
+            email_for_sending = account.email
+            user_email = account.email
 
         token = AccountService.send_change_email_email(
-            account=account, email=args.email, old_email=user_email, language=language, phase=args.phase
+            account=account,
+            email=email_for_sending,
+            old_email=user_email,
+            language=language,
+            phase=args.phase,
         )
         return {"result": "success", "data": token}
 
@@ -571,9 +580,9 @@ class ChangeEmailCheckApi(Resource):
         payload = console_ns.payload or {}
         args = ChangeEmailValidityPayload.model_validate(payload)
 
-        user_email = args.email
+        user_email = args.email.lower()
 
-        is_change_email_error_rate_limit = AccountService.is_change_email_error_rate_limit(args.email)
+        is_change_email_error_rate_limit = AccountService.is_change_email_error_rate_limit(user_email)
         if is_change_email_error_rate_limit:
             raise EmailChangeLimitError()
 
@@ -581,11 +590,13 @@ class ChangeEmailCheckApi(Resource):
         if token_data is None:
             raise InvalidTokenError()
 
-        if user_email != token_data.get("email"):
+        token_email = token_data.get("email")
+        normalized_token_email = token_email.lower() if isinstance(token_email, str) else token_email
+        if user_email != normalized_token_email:
             raise InvalidEmailError()
 
         if args.code != token_data.get("code"):
-            AccountService.add_change_email_error_rate_limit(args.email)
+            AccountService.add_change_email_error_rate_limit(user_email)
             raise EmailCodeError()
 
         # Verified, revoke the first token
@@ -596,8 +607,8 @@ class ChangeEmailCheckApi(Resource):
             user_email, code=args.code, old_email=token_data.get("old_email"), additional_data={}
         )
 
-        AccountService.reset_change_email_error_rate_limit(args.email)
-        return {"is_valid": True, "email": token_data.get("email"), "token": new_token}
+        AccountService.reset_change_email_error_rate_limit(user_email)
+        return {"is_valid": True, "email": normalized_token_email, "token": new_token}
 
 
 @console_ns.route("/account/change-email/reset")
@@ -611,11 +622,12 @@ class ChangeEmailResetApi(Resource):
     def post(self):
         payload = console_ns.payload or {}
         args = ChangeEmailResetPayload.model_validate(payload)
+        normalized_new_email = args.new_email.lower()
 
-        if AccountService.is_account_in_freeze(args.new_email):
+        if AccountService.is_account_in_freeze(normalized_new_email):
             raise AccountInFreezeError()
 
-        if not AccountService.check_email_unique(args.new_email):
+        if not AccountService.check_email_unique(normalized_new_email):
             raise EmailAlreadyInUseError()
 
         reset_data = AccountService.get_change_email_data(args.token)
@@ -626,13 +638,13 @@ class ChangeEmailResetApi(Resource):
 
         old_email = reset_data.get("old_email", "")
         current_user, _ = current_account_with_tenant()
-        if current_user.email != old_email:
+        if current_user.email.lower() != old_email.lower():
             raise AccountNotFound()
 
-        updated_account = AccountService.update_account_email(current_user, email=args.new_email)
+        updated_account = AccountService.update_account_email(current_user, email=normalized_new_email)
 
         AccountService.send_change_email_completed_notify_email(
-            email=args.new_email,
+            email=normalized_new_email,
         )
 
         return updated_account
@@ -645,8 +657,9 @@ class CheckEmailUnique(Resource):
     def post(self):
         payload = console_ns.payload or {}
         args = CheckEmailUniquePayload.model_validate(payload)
-        if AccountService.is_account_in_freeze(args.email):
+        normalized_email = args.email.lower()
+        if AccountService.is_account_in_freeze(normalized_email):
             raise AccountInFreezeError()
-        if not AccountService.check_email_unique(args.email):
+        if not AccountService.check_email_unique(normalized_email):
             raise EmailAlreadyInUseError()
         return {"result": "success"}
diff --git a/api/controllers/console/workspace/members.py b/api/controllers/console/workspace/members.py
index 0142e14fb0..e9bd2b8f94 100644
--- a/api/controllers/console/workspace/members.py
+++ b/api/controllers/console/workspace/members.py
@@ -116,26 +116,31 @@ class MemberInviteEmailApi(Resource):
             raise WorkspaceMembersLimitExceeded()
 
         for invitee_email in invitee_emails:
+            normalized_invitee_email = invitee_email.lower()
             try:
                 if not inviter.current_tenant:
                     raise ValueError("No current tenant")
                 token = RegisterService.invite_new_member(
-                    inviter.current_tenant, invitee_email, interface_language, role=invitee_role, inviter=inviter
+                    tenant=inviter.current_tenant,
+                    email=invitee_email,
+                    language=interface_language,
+                    role=invitee_role,
+                    inviter=inviter,
                 )
-                encoded_invitee_email = parse.quote(invitee_email)
+                encoded_invitee_email = parse.quote(normalized_invitee_email)
                 invitation_results.append(
                     {
                         "status": "success",
-                        "email": invitee_email,
+                        "email": normalized_invitee_email,
                         "url": f"{console_web_url}/activate?email={encoded_invitee_email}&token={token}",
                     }
                 )
             except AccountAlreadyInTenantError:
                 invitation_results.append(
-                    {"status": "success", "email": invitee_email, "url": f"{console_web_url}/signin"}
+                    {"status": "success", "email": normalized_invitee_email, "url": f"{console_web_url}/signin"}
                 )
             except Exception as e:
-                invitation_results.append({"status": "failed", "email": invitee_email, "message": str(e)})
+                invitation_results.append({"status": "failed", "email": normalized_invitee_email, "message": str(e)})
 
         return {
             "result": "success",
diff --git a/api/controllers/web/forgot_password.py b/api/controllers/web/forgot_password.py
index 690b76655f..91d206f727 100644
--- a/api/controllers/web/forgot_password.py
+++ b/api/controllers/web/forgot_password.py
@@ -4,7 +4,6 @@ import secrets
 from flask import request
 from flask_restx import Resource
 from pydantic import BaseModel, Field, field_validator
-from sqlalchemy import select
 from sqlalchemy.orm import Session
 
 from controllers.common.schema import register_schema_models
@@ -22,7 +21,7 @@ from controllers.web import web_ns
 from extensions.ext_database import db
 from libs.helper import EmailStr, extract_remote_ip
 from libs.password import hash_password, valid_password
-from models import Account
+from models.account import Account
 from services.account_service import AccountService
 
 
@@ -70,6 +69,9 @@ class ForgotPasswordSendEmailApi(Resource):
     def post(self):
         payload = ForgotPasswordSendPayload.model_validate(web_ns.payload or {})
 
+        request_email = payload.email
+        normalized_email = request_email.lower()
+
         ip_address = extract_remote_ip(request)
         if AccountService.is_email_send_ip_limit(ip_address):
             raise EmailSendIpLimitError()
@@ -80,12 +82,12 @@ class ForgotPasswordSendEmailApi(Resource):
             language = "en-US"
 
         with Session(db.engine) as session:
-            account = session.execute(select(Account).filter_by(email=payload.email)).scalar_one_or_none()
+            account = AccountService.get_account_by_email_with_case_fallback(request_email, session=session)
         token = None
         if account is None:
             raise AuthenticationFailedError()
         else:
-            token = AccountService.send_reset_password_email(account=account, email=payload.email, language=language)
+            token = AccountService.send_reset_password_email(account=account, email=normalized_email, language=language)
 
         return {"result": "success", "data": token}
 
@@ -104,9 +106,9 @@ class ForgotPasswordCheckApi(Resource):
     def post(self):
         payload = ForgotPasswordCheckPayload.model_validate(web_ns.payload or {})
 
-        user_email = payload.email
+        user_email = payload.email.lower()
 
-        is_forgot_password_error_rate_limit = AccountService.is_forgot_password_error_rate_limit(payload.email)
+        is_forgot_password_error_rate_limit = AccountService.is_forgot_password_error_rate_limit(user_email)
         if is_forgot_password_error_rate_limit:
             raise EmailPasswordResetLimitError()
 
@@ -114,11 +116,16 @@ class ForgotPasswordCheckApi(Resource):
         if token_data is None:
             raise InvalidTokenError()
 
-        if user_email != token_data.get("email"):
+        token_email = token_data.get("email")
+        if not isinstance(token_email, str):
+            raise InvalidEmailError()
+        normalized_token_email = token_email.lower()
+
+        if user_email != normalized_token_email:
             raise InvalidEmailError()
 
         if payload.code != token_data.get("code"):
-            AccountService.add_forgot_password_error_rate_limit(payload.email)
+            AccountService.add_forgot_password_error_rate_limit(user_email)
             raise EmailCodeError()
 
         # Verified, revoke the first token
@@ -126,11 +133,11 @@ class ForgotPasswordCheckApi(Resource):
 
         # Refresh token data by generating a new token
         _, new_token = AccountService.generate_reset_password_token(
-            user_email, code=payload.code, additional_data={"phase": "reset"}
+            token_email, code=payload.code, additional_data={"phase": "reset"}
         )
 
-        AccountService.reset_forgot_password_error_rate_limit(payload.email)
-        return {"is_valid": True, "email": token_data.get("email"), "token": new_token}
+        AccountService.reset_forgot_password_error_rate_limit(user_email)
+        return {"is_valid": True, "email": normalized_token_email, "token": new_token}
 
 
 @web_ns.route("/forgot-password/resets")
@@ -174,7 +181,7 @@ class ForgotPasswordResetApi(Resource):
         email = reset_data.get("email", "")
 
         with Session(db.engine) as session:
-            account = session.execute(select(Account).filter_by(email=email)).scalar_one_or_none()
+            account = AccountService.get_account_by_email_with_case_fallback(email, session=session)
 
             if account:
                 self._update_existing_account(account, password_hashed, salt, session)
diff --git a/api/controllers/web/login.py b/api/controllers/web/login.py
index 5847f4ae3a..e8053acdfd 100644
--- a/api/controllers/web/login.py
+++ b/api/controllers/web/login.py
@@ -197,25 +197,29 @@ class EmailCodeLoginApi(Resource):
         )
         args = parser.parse_args()
 
-        user_email = args["email"]
+        user_email = args["email"].lower()
 
         token_data = WebAppAuthService.get_email_code_login_data(args["token"])
         if token_data is None:
             raise InvalidTokenError()
 
-        if token_data["email"] != args["email"]:
+        token_email = token_data.get("email")
+        if not isinstance(token_email, str):
+            raise InvalidEmailError()
+        normalized_token_email = token_email.lower()
+        if normalized_token_email != user_email:
             raise InvalidEmailError()
 
         if token_data["code"] != args["code"]:
             raise EmailCodeError()
 
         WebAppAuthService.revoke_email_code_login_token(args["token"])
-        account = WebAppAuthService.get_user_through_email(user_email)
+        account = WebAppAuthService.get_user_through_email(token_email)
         if not account:
             raise AuthenticationFailedError()
 
         token = WebAppAuthService.login(account=account)
-        AccountService.reset_login_error_rate_limit(args["email"])
+        AccountService.reset_login_error_rate_limit(user_email)
         response = make_response({"result": "success", "data": {"access_token": token}})
         # set_access_token_to_cookie(request, response, token, samesite="None", httponly=False)
         return response
diff --git a/api/services/account_service.py b/api/services/account_service.py
index d38c9d5a66..709ef749bc 100644
--- a/api/services/account_service.py
+++ b/api/services/account_service.py
@@ -8,7 +8,7 @@ from hashlib import sha256
 from typing import Any, cast
 
 from pydantic import BaseModel
-from sqlalchemy import func
+from sqlalchemy import func, select
 from sqlalchemy.orm import Session
 from werkzeug.exceptions import Unauthorized
 
@@ -748,6 +748,21 @@ class AccountService:
         cls.email_code_login_rate_limiter.increment_rate_limit(email)
         return token
 
+    @staticmethod
+    def get_account_by_email_with_case_fallback(email: str, session: Session | None = None) -> Account | None:
+        """
+        Retrieve an account by email and fall back to the lowercase email if the original lookup fails.
+
+        This keeps backward compatibility for older records that stored uppercase emails while the
+        rest of the system gradually normalizes new inputs.
+        """
+        query_session = session or db.session
+        account = query_session.execute(select(Account).filter_by(email=email)).scalar_one_or_none()
+        if account or email == email.lower():
+            return account
+
+        return query_session.execute(select(Account).filter_by(email=email.lower())).scalar_one_or_none()
+
     @classmethod
     def get_email_code_login_data(cls, token: str) -> dict[str, Any] | None:
         return TokenManager.get_token_data(token, "email_code_login")
@@ -1363,16 +1378,22 @@ class RegisterService:
         if not inviter:
             raise ValueError("Inviter is required")
 
+        normalized_email = email.lower()
+
         """Invite new member"""
         with Session(db.engine) as session:
-            account = session.query(Account).filter_by(email=email).first()
+            account = AccountService.get_account_by_email_with_case_fallback(email, session=session)
 
         if not account:
             TenantService.check_member_permission(tenant, inviter, None, "add")
-            name = email.split("@")[0]
+            name = normalized_email.split("@")[0]
 
             account = cls.register(
-                email=email, name=name, language=language, status=AccountStatus.PENDING, is_setup=True
+                email=normalized_email,
+                name=name,
+                language=language,
+                status=AccountStatus.PENDING,
+                is_setup=True,
             )
             # Create new tenant member for invited tenant
             TenantService.create_tenant_member(tenant, account, role)
@@ -1394,7 +1415,7 @@ class RegisterService:
         # send email
         send_invite_member_mail_task.delay(
             language=language,
-            to=email,
+            to=account.email,
             token=token,
             inviter_name=inviter.name if inviter else "Dify",
             workspace_name=tenant.name,
@@ -1493,6 +1514,16 @@ class RegisterService:
             invitation: dict = json.loads(data)
             return invitation
 
+    @classmethod
+    def get_invitation_with_case_fallback(
+        cls, workspace_id: str | None, email: str | None, token: str
+    ) -> dict[str, Any] | None:
+        invitation = cls.get_invitation_if_token_valid(workspace_id, email, token)
+        if invitation or not email or email == email.lower():
+            return invitation
+        normalized_email = email.lower()
+        return cls.get_invitation_if_token_valid(workspace_id, normalized_email, token)
+
 
 def _generate_refresh_token(length: int = 64):
     token = secrets.token_hex(length)
diff --git a/api/services/webapp_auth_service.py b/api/services/webapp_auth_service.py
index 9bd797a45f..5ca0b63001 100644
--- a/api/services/webapp_auth_service.py
+++ b/api/services/webapp_auth_service.py
@@ -12,6 +12,7 @@ from libs.passport import PassportService
 from libs.password import compare_password
 from models import Account, AccountStatus
 from models.model import App, EndUser, Site
+from services.account_service import AccountService
 from services.app_service import AppService
 from services.enterprise.enterprise_service import EnterpriseService
 from services.errors.account import AccountLoginError, AccountNotFoundError, AccountPasswordError
@@ -32,7 +33,7 @@ class WebAppAuthService:
     @staticmethod
     def authenticate(email: str, password: str) -> Account:
         """authenticate account with email and password"""
-        account = db.session.query(Account).filter_by(email=email).first()
+        account = AccountService.get_account_by_email_with_case_fallback(email)
         if not account:
             raise AccountNotFoundError()
 
@@ -52,7 +53,7 @@ class WebAppAuthService:
 
     @classmethod
     def get_user_through_email(cls, email: str):
-        account = db.session.query(Account).where(Account.email == email).first()
+        account = AccountService.get_account_by_email_with_case_fallback(email)
         if not account:
             return None
 
diff --git a/api/tests/unit_tests/controllers/console/auth/test_account_activation.py b/api/tests/unit_tests/controllers/console/auth/test_account_activation.py
index da21e0e358..d3e864a75a 100644
--- a/api/tests/unit_tests/controllers/console/auth/test_account_activation.py
+++ b/api/tests/unit_tests/controllers/console/auth/test_account_activation.py
@@ -40,7 +40,7 @@ class TestActivateCheckApi:
             "tenant": tenant,
         }
 
-    @patch("controllers.console.auth.activate.RegisterService.get_invitation_if_token_valid")
+    @patch("controllers.console.auth.activate.RegisterService.get_invitation_with_case_fallback")
     def test_check_valid_invitation_token(self, mock_get_invitation, app, mock_invitation):
         """
         Test checking valid invitation token.
@@ -66,7 +66,7 @@ class TestActivateCheckApi:
         assert response["data"]["workspace_id"] == "workspace-123"
         assert response["data"]["email"] == "invitee@example.com"
 
-    @patch("controllers.console.auth.activate.RegisterService.get_invitation_if_token_valid")
+    @patch("controllers.console.auth.activate.RegisterService.get_invitation_with_case_fallback")
     def test_check_invalid_invitation_token(self, mock_get_invitation, app):
         """
         Test checking invalid invitation token.
@@ -88,7 +88,7 @@ class TestActivateCheckApi:
         # Assert
         assert response["is_valid"] is False
 
-    @patch("controllers.console.auth.activate.RegisterService.get_invitation_if_token_valid")
+    @patch("controllers.console.auth.activate.RegisterService.get_invitation_with_case_fallback")
     def test_check_token_without_workspace_id(self, mock_get_invitation, app, mock_invitation):
         """
         Test checking token without workspace ID.
@@ -109,7 +109,7 @@ class TestActivateCheckApi:
         assert response["is_valid"] is True
         mock_get_invitation.assert_called_once_with(None, "invitee@example.com", "valid_token")
 
-    @patch("controllers.console.auth.activate.RegisterService.get_invitation_if_token_valid")
+    @patch("controllers.console.auth.activate.RegisterService.get_invitation_with_case_fallback")
     def test_check_token_without_email(self, mock_get_invitation, app, mock_invitation):
         """
         Test checking token without email parameter.
@@ -130,6 +130,20 @@ class TestActivateCheckApi:
         assert response["is_valid"] is True
         mock_get_invitation.assert_called_once_with("workspace-123", None, "valid_token")
 
+    @patch("controllers.console.auth.activate.RegisterService.get_invitation_with_case_fallback")
+    def test_check_token_normalizes_email_to_lowercase(self, mock_get_invitation, app, mock_invitation):
+        """Ensure token validation uses lowercase emails."""
+        mock_get_invitation.return_value = mock_invitation
+
+        with app.test_request_context(
+            "/activate/check?workspace_id=workspace-123&email=Invitee@Example.com&token=valid_token"
+        ):
+            api = ActivateCheckApi()
+            response = api.get()
+
+        assert response["is_valid"] is True
+        mock_get_invitation.assert_called_once_with("workspace-123", "Invitee@Example.com", "valid_token")
+
 
 class TestActivateApi:
     """Test cases for account activation endpoint."""
@@ -212,7 +226,7 @@ class TestActivateApi:
         mock_revoke_token.assert_called_once_with("workspace-123", "invitee@example.com", "valid_token")
         mock_db.session.commit.assert_called_once()
 
-    @patch("controllers.console.auth.activate.RegisterService.get_invitation_if_token_valid")
+    @patch("controllers.console.auth.activate.RegisterService.get_invitation_with_case_fallback")
     def test_activation_with_invalid_token(self, mock_get_invitation, app):
         """
         Test account activation with invalid token.
@@ -241,7 +255,7 @@ class TestActivateApi:
             with pytest.raises(AlreadyActivateError):
                 api.post()
 
-    @patch("controllers.console.auth.activate.RegisterService.get_invitation_if_token_valid")
+    @patch("controllers.console.auth.activate.RegisterService.get_invitation_with_case_fallback")
     @patch("controllers.console.auth.activate.RegisterService.revoke_token")
     @patch("controllers.console.auth.activate.db")
     def test_activation_sets_interface_theme(
@@ -290,7 +304,7 @@ class TestActivateApi:
             ("es-ES", "Europe/Madrid"),
         ],
     )
-    @patch("controllers.console.auth.activate.RegisterService.get_invitation_if_token_valid")
+    @patch("controllers.console.auth.activate.RegisterService.get_invitation_with_case_fallback")
     @patch("controllers.console.auth.activate.RegisterService.revoke_token")
     @patch("controllers.console.auth.activate.db")
     def test_activation_with_different_locales(
@@ -336,7 +350,7 @@ class TestActivateApi:
         assert mock_account.interface_language == language
         assert mock_account.timezone == timezone
 
-    @patch("controllers.console.auth.activate.RegisterService.get_invitation_if_token_valid")
+    @patch("controllers.console.auth.activate.RegisterService.get_invitation_with_case_fallback")
     @patch("controllers.console.auth.activate.RegisterService.revoke_token")
     @patch("controllers.console.auth.activate.db")
     def test_activation_returns_success_response(
@@ -376,7 +390,7 @@ class TestActivateApi:
         # Assert
         assert response == {"result": "success"}
 
-    @patch("controllers.console.auth.activate.RegisterService.get_invitation_if_token_valid")
+    @patch("controllers.console.auth.activate.RegisterService.get_invitation_with_case_fallback")
     @patch("controllers.console.auth.activate.RegisterService.revoke_token")
     @patch("controllers.console.auth.activate.db")
     def test_activation_without_workspace_id(
@@ -415,3 +429,37 @@ class TestActivateApi:
         # Assert
         assert response["result"] == "success"
         mock_revoke_token.assert_called_once_with(None, "invitee@example.com", "valid_token")
+
+    @patch("controllers.console.auth.activate.RegisterService.get_invitation_with_case_fallback")
+    @patch("controllers.console.auth.activate.RegisterService.revoke_token")
+    @patch("controllers.console.auth.activate.db")
+    def test_activation_normalizes_email_before_lookup(
+        self,
+        mock_db,
+        mock_revoke_token,
+        mock_get_invitation,
+        app,
+        mock_invitation,
+        mock_account,
+    ):
+        """Ensure uppercase emails are normalized before lookup and revocation."""
+        mock_get_invitation.return_value = mock_invitation
+
+        with app.test_request_context(
+            "/activate",
+            method="POST",
+            json={
+                "workspace_id": "workspace-123",
+                "email": "Invitee@Example.com",
+                "token": "valid_token",
+                "name": "John Doe",
+                "interface_language": "en-US",
+                "timezone": "UTC",
+            },
+        ):
+            api = ActivateApi()
+            response = api.post()
+
+        assert response["result"] == "success"
+        mock_get_invitation.assert_called_once_with("workspace-123", "Invitee@Example.com", "valid_token")
+        mock_revoke_token.assert_called_once_with("workspace-123", "invitee@example.com", "valid_token")
diff --git a/api/tests/unit_tests/controllers/console/auth/test_authentication_security.py b/api/tests/unit_tests/controllers/console/auth/test_authentication_security.py
index eb21920117..cb4fe40944 100644
--- a/api/tests/unit_tests/controllers/console/auth/test_authentication_security.py
+++ b/api/tests/unit_tests/controllers/console/auth/test_authentication_security.py
@@ -34,7 +34,7 @@ class TestAuthenticationSecurity:
     @patch("controllers.console.auth.login.AccountService.authenticate")
     @patch("controllers.console.auth.login.AccountService.add_login_error_rate_limit")
     @patch("controllers.console.auth.login.dify_config.BILLING_ENABLED", False)
-    @patch("controllers.console.auth.login.RegisterService.get_invitation_if_token_valid")
+    @patch("controllers.console.auth.login.RegisterService.get_invitation_with_case_fallback")
     def test_login_invalid_email_with_registration_allowed(
         self, mock_get_invitation, mock_add_rate_limit, mock_authenticate, mock_is_rate_limit, mock_features, mock_db
     ):
@@ -67,7 +67,7 @@ class TestAuthenticationSecurity:
     @patch("controllers.console.auth.login.AccountService.authenticate")
     @patch("controllers.console.auth.login.AccountService.add_login_error_rate_limit")
     @patch("controllers.console.auth.login.dify_config.BILLING_ENABLED", False)
-    @patch("controllers.console.auth.login.RegisterService.get_invitation_if_token_valid")
+    @patch("controllers.console.auth.login.RegisterService.get_invitation_with_case_fallback")
     def test_login_wrong_password_returns_error(
         self, mock_get_invitation, mock_add_rate_limit, mock_authenticate, mock_is_rate_limit, mock_db
     ):
@@ -100,7 +100,7 @@ class TestAuthenticationSecurity:
     @patch("controllers.console.auth.login.AccountService.authenticate")
     @patch("controllers.console.auth.login.AccountService.add_login_error_rate_limit")
     @patch("controllers.console.auth.login.dify_config.BILLING_ENABLED", False)
-    @patch("controllers.console.auth.login.RegisterService.get_invitation_if_token_valid")
+    @patch("controllers.console.auth.login.RegisterService.get_invitation_with_case_fallback")
     def test_login_invalid_email_with_registration_disabled(
         self, mock_get_invitation, mock_add_rate_limit, mock_authenticate, mock_is_rate_limit, mock_features, mock_db
     ):
diff --git a/api/tests/unit_tests/controllers/console/auth/test_email_register.py b/api/tests/unit_tests/controllers/console/auth/test_email_register.py
new file mode 100644
index 0000000000..724c80f18c
--- /dev/null
+++ b/api/tests/unit_tests/controllers/console/auth/test_email_register.py
@@ -0,0 +1,177 @@
+from types import SimpleNamespace
+from unittest.mock import MagicMock, patch
+
+import pytest
+from flask import Flask
+
+from controllers.console.auth.email_register import (
+    EmailRegisterCheckApi,
+    EmailRegisterResetApi,
+    EmailRegisterSendEmailApi,
+)
+from services.account_service import AccountService
+
+
+@pytest.fixture
+def app():
+    flask_app = Flask(__name__)
+    flask_app.config["TESTING"] = True
+    return flask_app
+
+
+class TestEmailRegisterSendEmailApi:
+    @patch("controllers.console.auth.email_register.Session")
+    @patch("controllers.console.auth.email_register.AccountService.get_account_by_email_with_case_fallback")
+    @patch("controllers.console.auth.email_register.AccountService.send_email_register_email")
+    @patch("controllers.console.auth.email_register.BillingService.is_email_in_freeze")
+    @patch("controllers.console.auth.email_register.AccountService.is_email_send_ip_limit", return_value=False)
+    @patch("controllers.console.auth.email_register.extract_remote_ip", return_value="127.0.0.1")
+    def test_send_email_normalizes_and_falls_back(
+        self,
+        mock_extract_ip,
+        mock_is_email_send_ip_limit,
+        mock_is_freeze,
+        mock_send_mail,
+        mock_get_account,
+        mock_session_cls,
+        app,
+    ):
+        mock_send_mail.return_value = "token-123"
+        mock_is_freeze.return_value = False
+        mock_account = MagicMock()
+
+        mock_session = MagicMock()
+        mock_session_cls.return_value.__enter__.return_value = mock_session
+        mock_get_account.return_value = mock_account
+
+        feature_flags = SimpleNamespace(enable_email_password_login=True, is_allow_register=True)
+        with (
+            patch("controllers.console.auth.email_register.db", SimpleNamespace(engine="engine")),
+            patch("controllers.console.auth.email_register.dify_config", SimpleNamespace(BILLING_ENABLED=True)),
+            patch("controllers.console.wraps.dify_config", SimpleNamespace(EDITION="CLOUD")),
+            patch("controllers.console.wraps.FeatureService.get_system_features", return_value=feature_flags),
+        ):
+            with app.test_request_context(
+                "/email-register/send-email",
+                method="POST",
+                json={"email": "Invitee@Example.com", "language": "en-US"},
+            ):
+                response = EmailRegisterSendEmailApi().post()
+
+        assert response == {"result": "success", "data": "token-123"}
+        mock_is_freeze.assert_called_once_with("invitee@example.com")
+        mock_send_mail.assert_called_once_with(email="invitee@example.com", account=mock_account, language="en-US")
+        mock_get_account.assert_called_once_with("Invitee@Example.com", session=mock_session)
+        mock_extract_ip.assert_called_once()
+        mock_is_email_send_ip_limit.assert_called_once_with("127.0.0.1")
+
+
+class TestEmailRegisterCheckApi:
+    @patch("controllers.console.auth.email_register.AccountService.reset_email_register_error_rate_limit")
+    @patch("controllers.console.auth.email_register.AccountService.generate_email_register_token")
+    @patch("controllers.console.auth.email_register.AccountService.revoke_email_register_token")
+    @patch("controllers.console.auth.email_register.AccountService.add_email_register_error_rate_limit")
+    @patch("controllers.console.auth.email_register.AccountService.get_email_register_data")
+    @patch("controllers.console.auth.email_register.AccountService.is_email_register_error_rate_limit")
+    def test_validity_normalizes_email_before_checks(
+        self,
+        mock_rate_limit_check,
+        mock_get_data,
+        mock_add_rate,
+        mock_revoke,
+        mock_generate_token,
+        mock_reset_rate,
+        app,
+    ):
+        mock_rate_limit_check.return_value = False
+        mock_get_data.return_value = {"email": "User@Example.com", "code": "4321"}
+        mock_generate_token.return_value = (None, "new-token")
+
+        feature_flags = SimpleNamespace(enable_email_password_login=True, is_allow_register=True)
+        with (
+            patch("controllers.console.auth.email_register.db", SimpleNamespace(engine="engine")),
+            patch("controllers.console.wraps.dify_config", SimpleNamespace(EDITION="CLOUD")),
+            patch("controllers.console.wraps.FeatureService.get_system_features", return_value=feature_flags),
+        ):
+            with app.test_request_context(
+                "/email-register/validity",
+                method="POST",
+                json={"email": "User@Example.com", "code": "4321", "token": "token-123"},
+            ):
+                response = EmailRegisterCheckApi().post()
+
+        assert response == {"is_valid": True, "email": "user@example.com", "token": "new-token"}
+        mock_rate_limit_check.assert_called_once_with("user@example.com")
+        mock_generate_token.assert_called_once_with(
+            "user@example.com", code="4321", additional_data={"phase": "register"}
+        )
+        mock_reset_rate.assert_called_once_with("user@example.com")
+        mock_add_rate.assert_not_called()
+        mock_revoke.assert_called_once_with("token-123")
+
+
+class TestEmailRegisterResetApi:
+    @patch("controllers.console.auth.email_register.AccountService.reset_login_error_rate_limit")
+    @patch("controllers.console.auth.email_register.AccountService.login")
+    @patch("controllers.console.auth.email_register.EmailRegisterResetApi._create_new_account")
+    @patch("controllers.console.auth.email_register.Session")
+    @patch("controllers.console.auth.email_register.AccountService.get_account_by_email_with_case_fallback")
+    @patch("controllers.console.auth.email_register.AccountService.revoke_email_register_token")
+    @patch("controllers.console.auth.email_register.AccountService.get_email_register_data")
+    @patch("controllers.console.auth.email_register.extract_remote_ip", return_value="127.0.0.1")
+    def test_reset_creates_account_with_normalized_email(
+        self,
+        mock_extract_ip,
+        mock_get_data,
+        mock_revoke_token,
+        mock_get_account,
+        mock_session_cls,
+        mock_create_account,
+        mock_login,
+        mock_reset_login_rate,
+        app,
+    ):
+        mock_get_data.return_value = {"phase": "register", "email": "Invitee@Example.com"}
+        mock_create_account.return_value = MagicMock()
+        token_pair = MagicMock()
+        token_pair.model_dump.return_value = {"access_token": "a", "refresh_token": "r"}
+        mock_login.return_value = token_pair
+
+        mock_session = MagicMock()
+        mock_session_cls.return_value.__enter__.return_value = mock_session
+        mock_get_account.return_value = None
+
+        feature_flags = SimpleNamespace(enable_email_password_login=True, is_allow_register=True)
+        with (
+            patch("controllers.console.auth.email_register.db", SimpleNamespace(engine="engine")),
+            patch("controllers.console.wraps.dify_config", SimpleNamespace(EDITION="CLOUD")),
+            patch("controllers.console.wraps.FeatureService.get_system_features", return_value=feature_flags),
+        ):
+            with app.test_request_context(
+                "/email-register",
+                method="POST",
+                json={"token": "token-123", "new_password": "ValidPass123!", "password_confirm": "ValidPass123!"},
+            ):
+                response = EmailRegisterResetApi().post()
+
+        assert response == {"result": "success", "data": {"access_token": "a", "refresh_token": "r"}}
+        mock_create_account.assert_called_once_with("invitee@example.com", "ValidPass123!")
+        mock_reset_login_rate.assert_called_once_with("invitee@example.com")
+        mock_revoke_token.assert_called_once_with("token-123")
+        mock_extract_ip.assert_called_once()
+        mock_get_account.assert_called_once_with("Invitee@Example.com", session=mock_session)
+
+
+def test_get_account_by_email_with_case_fallback_uses_lowercase_lookup():
+    mock_session = MagicMock()
+    first_query = MagicMock()
+    first_query.scalar_one_or_none.return_value = None
+    expected_account = MagicMock()
+    second_query = MagicMock()
+    second_query.scalar_one_or_none.return_value = expected_account
+    mock_session.execute.side_effect = [first_query, second_query]
+
+    account = AccountService.get_account_by_email_with_case_fallback("Case@Test.com", session=mock_session)
+
+    assert account is expected_account
+    assert mock_session.execute.call_count == 2
diff --git a/api/tests/unit_tests/controllers/console/auth/test_forgot_password.py b/api/tests/unit_tests/controllers/console/auth/test_forgot_password.py
new file mode 100644
index 0000000000..8403777dc9
--- /dev/null
+++ b/api/tests/unit_tests/controllers/console/auth/test_forgot_password.py
@@ -0,0 +1,176 @@
+from types import SimpleNamespace
+from unittest.mock import MagicMock, patch
+
+import pytest
+from flask import Flask
+
+from controllers.console.auth.forgot_password import (
+    ForgotPasswordCheckApi,
+    ForgotPasswordResetApi,
+    ForgotPasswordSendEmailApi,
+)
+from services.account_service import AccountService
+
+
+@pytest.fixture
+def app():
+    flask_app = Flask(__name__)
+    flask_app.config["TESTING"] = True
+    return flask_app
+
+
+class TestForgotPasswordSendEmailApi:
+    @patch("controllers.console.auth.forgot_password.Session")
+    @patch("controllers.console.auth.forgot_password.AccountService.get_account_by_email_with_case_fallback")
+    @patch("controllers.console.auth.forgot_password.AccountService.send_reset_password_email")
+    @patch("controllers.console.auth.forgot_password.AccountService.is_email_send_ip_limit", return_value=False)
+    @patch("controllers.console.auth.forgot_password.extract_remote_ip", return_value="127.0.0.1")
+    def test_send_normalizes_email(
+        self,
+        mock_extract_ip,
+        mock_is_ip_limit,
+        mock_send_email,
+        mock_get_account,
+        mock_session_cls,
+        app,
+    ):
+        mock_account = MagicMock()
+        mock_get_account.return_value = mock_account
+        mock_send_email.return_value = "token-123"
+        mock_session = MagicMock()
+        mock_session_cls.return_value.__enter__.return_value = mock_session
+
+        wraps_features = SimpleNamespace(enable_email_password_login=True, is_allow_register=True)
+        controller_features = SimpleNamespace(is_allow_register=True)
+        with (
+            patch("controllers.console.auth.forgot_password.db", SimpleNamespace(engine="engine")),
+            patch(
+                "controllers.console.auth.forgot_password.FeatureService.get_system_features",
+                return_value=controller_features,
+            ),
+            patch("controllers.console.wraps.dify_config", SimpleNamespace(EDITION="CLOUD")),
+            patch("controllers.console.wraps.FeatureService.get_system_features", return_value=wraps_features),
+        ):
+            with app.test_request_context(
+                "/forgot-password",
+                method="POST",
+                json={"email": "User@Example.com", "language": "zh-Hans"},
+            ):
+                response = ForgotPasswordSendEmailApi().post()
+
+        assert response == {"result": "success", "data": "token-123"}
+        mock_get_account.assert_called_once_with("User@Example.com", session=mock_session)
+        mock_send_email.assert_called_once_with(
+            account=mock_account,
+            email="user@example.com",
+            language="zh-Hans",
+            is_allow_register=True,
+        )
+        mock_is_ip_limit.assert_called_once_with("127.0.0.1")
+        mock_extract_ip.assert_called_once()
+
+
+class TestForgotPasswordCheckApi:
+    @patch("controllers.console.auth.forgot_password.AccountService.reset_forgot_password_error_rate_limit")
+    @patch("controllers.console.auth.forgot_password.AccountService.generate_reset_password_token")
+    @patch("controllers.console.auth.forgot_password.AccountService.revoke_reset_password_token")
+    @patch("controllers.console.auth.forgot_password.AccountService.add_forgot_password_error_rate_limit")
+    @patch("controllers.console.auth.forgot_password.AccountService.get_reset_password_data")
+    @patch("controllers.console.auth.forgot_password.AccountService.is_forgot_password_error_rate_limit")
+    def test_check_normalizes_email(
+        self,
+        mock_rate_limit_check,
+        mock_get_data,
+        mock_add_rate,
+        mock_revoke_token,
+        mock_generate_token,
+        mock_reset_rate,
+        app,
+    ):
+        mock_rate_limit_check.return_value = False
+        mock_get_data.return_value = {"email": "Admin@Example.com", "code": "4321"}
+        mock_generate_token.return_value = (None, "new-token")
+
+        wraps_features = SimpleNamespace(enable_email_password_login=True)
+        with (
+            patch("controllers.console.wraps.dify_config", SimpleNamespace(EDITION="CLOUD")),
+            patch("controllers.console.wraps.FeatureService.get_system_features", return_value=wraps_features),
+        ):
+            with app.test_request_context(
+                "/forgot-password/validity",
+                method="POST",
+                json={"email": "ADMIN@Example.com", "code": "4321", "token": "token-123"},
+            ):
+                response = ForgotPasswordCheckApi().post()
+
+        assert response == {"is_valid": True, "email": "admin@example.com", "token": "new-token"}
+        mock_rate_limit_check.assert_called_once_with("admin@example.com")
+        mock_generate_token.assert_called_once_with(
+            "Admin@Example.com",
+            code="4321",
+            additional_data={"phase": "reset"},
+        )
+        mock_reset_rate.assert_called_once_with("admin@example.com")
+        mock_add_rate.assert_not_called()
+        mock_revoke_token.assert_called_once_with("token-123")
+
+
+class TestForgotPasswordResetApi:
+    @patch("controllers.console.auth.forgot_password.ForgotPasswordResetApi._update_existing_account")
+    @patch("controllers.console.auth.forgot_password.Session")
+    @patch("controllers.console.auth.forgot_password.AccountService.get_account_by_email_with_case_fallback")
+    @patch("controllers.console.auth.forgot_password.AccountService.revoke_reset_password_token")
+    @patch("controllers.console.auth.forgot_password.AccountService.get_reset_password_data")
+    def test_reset_fetches_account_with_original_email(
+        self,
+        mock_get_reset_data,
+        mock_revoke_token,
+        mock_get_account,
+        mock_session_cls,
+        mock_update_account,
+        app,
+    ):
+        mock_get_reset_data.return_value = {"phase": "reset", "email": "User@Example.com"}
+        mock_account = MagicMock()
+        mock_get_account.return_value = mock_account
+
+        mock_session = MagicMock()
+        mock_session_cls.return_value.__enter__.return_value = mock_session
+
+        wraps_features = SimpleNamespace(enable_email_password_login=True)
+        with (
+            patch("controllers.console.auth.forgot_password.db", SimpleNamespace(engine="engine")),
+            patch("controllers.console.wraps.dify_config", SimpleNamespace(EDITION="CLOUD")),
+            patch("controllers.console.wraps.FeatureService.get_system_features", return_value=wraps_features),
+        ):
+            with app.test_request_context(
+                "/forgot-password/resets",
+                method="POST",
+                json={
+                    "token": "token-123",
+                    "new_password": "ValidPass123!",
+                    "password_confirm": "ValidPass123!",
+                },
+            ):
+                response = ForgotPasswordResetApi().post()
+
+        assert response == {"result": "success"}
+        mock_get_reset_data.assert_called_once_with("token-123")
+        mock_revoke_token.assert_called_once_with("token-123")
+        mock_get_account.assert_called_once_with("User@Example.com", session=mock_session)
+        mock_update_account.assert_called_once()
+
+
+def test_get_account_by_email_with_case_fallback_uses_lowercase_lookup():
+    mock_session = MagicMock()
+    first_query = MagicMock()
+    first_query.scalar_one_or_none.return_value = None
+    expected_account = MagicMock()
+    second_query = MagicMock()
+    second_query.scalar_one_or_none.return_value = expected_account
+    mock_session.execute.side_effect = [first_query, second_query]
+
+    account = AccountService.get_account_by_email_with_case_fallback("Mixed@Test.com", session=mock_session)
+
+    assert account is expected_account
+    assert mock_session.execute.call_count == 2
diff --git a/api/tests/unit_tests/controllers/console/auth/test_login_logout.py b/api/tests/unit_tests/controllers/console/auth/test_login_logout.py
index 3a2cf7bad7..560971206f 100644
--- a/api/tests/unit_tests/controllers/console/auth/test_login_logout.py
+++ b/api/tests/unit_tests/controllers/console/auth/test_login_logout.py
@@ -76,7 +76,7 @@ class TestLoginApi:
     @patch("controllers.console.wraps.db")
     @patch("controllers.console.auth.login.dify_config.BILLING_ENABLED", False)
     @patch("controllers.console.auth.login.AccountService.is_login_error_rate_limit")
-    @patch("controllers.console.auth.login.RegisterService.get_invitation_if_token_valid")
+    @patch("controllers.console.auth.login.RegisterService.get_invitation_with_case_fallback")
     @patch("controllers.console.auth.login.AccountService.authenticate")
     @patch("controllers.console.auth.login.TenantService.get_join_tenants")
     @patch("controllers.console.auth.login.AccountService.login")
@@ -120,7 +120,7 @@ class TestLoginApi:
             response = login_api.post()
 
         # Assert
-        mock_authenticate.assert_called_once_with("test@example.com", "ValidPass123!")
+        mock_authenticate.assert_called_once_with("test@example.com", "ValidPass123!", None)
         mock_login.assert_called_once()
         mock_reset_rate_limit.assert_called_once_with("test@example.com")
         assert response.json["result"] == "success"
@@ -128,7 +128,7 @@ class TestLoginApi:
     @patch("controllers.console.wraps.db")
     @patch("controllers.console.auth.login.dify_config.BILLING_ENABLED", False)
     @patch("controllers.console.auth.login.AccountService.is_login_error_rate_limit")
-    @patch("controllers.console.auth.login.RegisterService.get_invitation_if_token_valid")
+    @patch("controllers.console.auth.login.RegisterService.get_invitation_with_case_fallback")
     @patch("controllers.console.auth.login.AccountService.authenticate")
     @patch("controllers.console.auth.login.TenantService.get_join_tenants")
     @patch("controllers.console.auth.login.AccountService.login")
@@ -182,7 +182,7 @@ class TestLoginApi:
     @patch("controllers.console.wraps.db")
     @patch("controllers.console.auth.login.dify_config.BILLING_ENABLED", False)
     @patch("controllers.console.auth.login.AccountService.is_login_error_rate_limit")
-    @patch("controllers.console.auth.login.RegisterService.get_invitation_if_token_valid")
+    @patch("controllers.console.auth.login.RegisterService.get_invitation_with_case_fallback")
     def test_login_fails_when_rate_limited(self, mock_get_invitation, mock_is_rate_limit, mock_db, app):
         """
         Test login rejection when rate limit is exceeded.
@@ -230,7 +230,7 @@ class TestLoginApi:
     @patch("controllers.console.wraps.db")
     @patch("controllers.console.auth.login.dify_config.BILLING_ENABLED", False)
     @patch("controllers.console.auth.login.AccountService.is_login_error_rate_limit")
-    @patch("controllers.console.auth.login.RegisterService.get_invitation_if_token_valid")
+    @patch("controllers.console.auth.login.RegisterService.get_invitation_with_case_fallback")
     @patch("controllers.console.auth.login.AccountService.authenticate")
     @patch("controllers.console.auth.login.AccountService.add_login_error_rate_limit")
     def test_login_fails_with_invalid_credentials(
@@ -269,7 +269,7 @@ class TestLoginApi:
     @patch("controllers.console.wraps.db")
     @patch("controllers.console.auth.login.dify_config.BILLING_ENABLED", False)
     @patch("controllers.console.auth.login.AccountService.is_login_error_rate_limit")
-    @patch("controllers.console.auth.login.RegisterService.get_invitation_if_token_valid")
+    @patch("controllers.console.auth.login.RegisterService.get_invitation_with_case_fallback")
     @patch("controllers.console.auth.login.AccountService.authenticate")
     def test_login_fails_for_banned_account(
         self, mock_authenticate, mock_get_invitation, mock_is_rate_limit, mock_db, app
@@ -298,7 +298,7 @@ class TestLoginApi:
     @patch("controllers.console.wraps.db")
     @patch("controllers.console.auth.login.dify_config.BILLING_ENABLED", False)
     @patch("controllers.console.auth.login.AccountService.is_login_error_rate_limit")
-    @patch("controllers.console.auth.login.RegisterService.get_invitation_if_token_valid")
+    @patch("controllers.console.auth.login.RegisterService.get_invitation_with_case_fallback")
     @patch("controllers.console.auth.login.AccountService.authenticate")
     @patch("controllers.console.auth.login.TenantService.get_join_tenants")
     @patch("controllers.console.auth.login.FeatureService.get_system_features")
@@ -343,7 +343,7 @@ class TestLoginApi:
     @patch("controllers.console.wraps.db")
     @patch("controllers.console.auth.login.dify_config.BILLING_ENABLED", False)
     @patch("controllers.console.auth.login.AccountService.is_login_error_rate_limit")
-    @patch("controllers.console.auth.login.RegisterService.get_invitation_if_token_valid")
+    @patch("controllers.console.auth.login.RegisterService.get_invitation_with_case_fallback")
     def test_login_invitation_email_mismatch(self, mock_get_invitation, mock_is_rate_limit, mock_db, app):
         """
         Test login failure when invitation email doesn't match login email.
@@ -371,6 +371,52 @@ class TestLoginApi:
             with pytest.raises(InvalidEmailError):
                 login_api.post()
 
+    @patch("controllers.console.wraps.db")
+    @patch("controllers.console.auth.login.dify_config.BILLING_ENABLED", False)
+    @patch("controllers.console.auth.login.AccountService.is_login_error_rate_limit")
+    @patch("controllers.console.auth.login.RegisterService.get_invitation_with_case_fallback")
+    @patch("controllers.console.auth.login.AccountService.authenticate")
+    @patch("controllers.console.auth.login.AccountService.add_login_error_rate_limit")
+    @patch("controllers.console.auth.login.TenantService.get_join_tenants")
+    @patch("controllers.console.auth.login.AccountService.login")
+    @patch("controllers.console.auth.login.AccountService.reset_login_error_rate_limit")
+    def test_login_retries_with_lowercase_email(
+        self,
+        mock_reset_rate_limit,
+        mock_login_service,
+        mock_get_tenants,
+        mock_add_rate_limit,
+        mock_authenticate,
+        mock_get_invitation,
+        mock_is_rate_limit,
+        mock_db,
+        app,
+        mock_account,
+        mock_token_pair,
+    ):
+        """Test that login retries with lowercase email when uppercase lookup fails."""
+        mock_db.session.query.return_value.first.return_value = MagicMock()
+        mock_is_rate_limit.return_value = False
+        mock_get_invitation.return_value = None
+        mock_authenticate.side_effect = [AccountPasswordError("Invalid"), mock_account]
+        mock_get_tenants.return_value = [MagicMock()]
+        mock_login_service.return_value = mock_token_pair
+
+        with app.test_request_context(
+            "/login",
+            method="POST",
+            json={"email": "Upper@Example.com", "password": encode_password("ValidPass123!")},
+        ):
+            response = LoginApi().post()
+
+        assert response.json["result"] == "success"
+        assert mock_authenticate.call_args_list == [
+            (("Upper@Example.com", "ValidPass123!", None), {}),
+            (("upper@example.com", "ValidPass123!", None), {}),
+        ]
+        mock_add_rate_limit.assert_not_called()
+        mock_reset_rate_limit.assert_called_once_with("upper@example.com")
+
 
 class TestLogoutApi:
     """Test cases for the LogoutApi endpoint."""
diff --git a/api/tests/unit_tests/controllers/console/auth/test_oauth.py b/api/tests/unit_tests/controllers/console/auth/test_oauth.py
index 3ddfcdb832..6345c2ab23 100644
--- a/api/tests/unit_tests/controllers/console/auth/test_oauth.py
+++ b/api/tests/unit_tests/controllers/console/auth/test_oauth.py
@@ -12,6 +12,7 @@ from controllers.console.auth.oauth import (
 )
 from libs.oauth import OAuthUserInfo
 from models.account import AccountStatus
+from services.account_service import AccountService
 from services.errors.account import AccountRegisterError
 
 
@@ -215,6 +216,34 @@ class TestOAuthCallback:
         assert status_code == 400
         assert response["error"] == expected_error
 
+    @patch("controllers.console.auth.oauth.dify_config")
+    @patch("controllers.console.auth.oauth.get_oauth_providers")
+    @patch("controllers.console.auth.oauth.RegisterService")
+    @patch("controllers.console.auth.oauth.redirect")
+    def test_invitation_comparison_is_case_insensitive(
+        self,
+        mock_redirect,
+        mock_register_service,
+        mock_get_providers,
+        mock_config,
+        resource,
+        app,
+        oauth_setup,
+    ):
+        mock_config.CONSOLE_WEB_URL = "http://localhost:3000"
+        oauth_setup["provider"].get_user_info.return_value = OAuthUserInfo(
+            id="123", name="Test User", email="User@Example.com"
+        )
+        mock_get_providers.return_value = {"github": oauth_setup["provider"]}
+        mock_register_service.is_valid_invite_token.return_value = True
+        mock_register_service.get_invitation_by_token.return_value = {"email": "user@example.com"}
+
+        with app.test_request_context("/auth/oauth/github/callback?code=test_code&state=invite123"):
+            resource.get("github")
+
+        mock_register_service.get_invitation_by_token.assert_called_once_with(token="invite123")
+        mock_redirect.assert_called_once_with("http://localhost:3000/signin/invite-settings?invite_token=invite123")
+
     @pytest.mark.parametrize(
         ("account_status", "expected_redirect"),
         [
@@ -395,12 +424,12 @@ class TestAccountGeneration:
         account.name = "Test User"
         return account
 
-    @patch("controllers.console.auth.oauth.db")
-    @patch("controllers.console.auth.oauth.Account")
+    @patch("controllers.console.auth.oauth.AccountService.get_account_by_email_with_case_fallback")
     @patch("controllers.console.auth.oauth.Session")
-    @patch("controllers.console.auth.oauth.select")
+    @patch("controllers.console.auth.oauth.Account")
+    @patch("controllers.console.auth.oauth.db")
     def test_should_get_account_by_openid_or_email(
-        self, mock_select, mock_session, mock_account_model, mock_db, user_info, mock_account
+        self, mock_db, mock_account_model, mock_session, mock_get_account, user_info, mock_account
     ):
         # Mock db.engine for Session creation
         mock_db.engine = MagicMock()
@@ -410,15 +439,31 @@ class TestAccountGeneration:
         result = _get_account_by_openid_or_email("github", user_info)
         assert result == mock_account
         mock_account_model.get_by_openid.assert_called_once_with("github", "123")
+        mock_get_account.assert_not_called()
 
-        # Test fallback to email
+        # Test fallback to email lookup
         mock_account_model.get_by_openid.return_value = None
         mock_session_instance = MagicMock()
-        mock_session_instance.execute.return_value.scalar_one_or_none.return_value = mock_account
         mock_session.return_value.__enter__.return_value = mock_session_instance
+        mock_get_account.return_value = mock_account
 
         result = _get_account_by_openid_or_email("github", user_info)
         assert result == mock_account
+        mock_get_account.assert_called_once_with(user_info.email, session=mock_session_instance)
+
+    def test_get_account_by_email_with_case_fallback_uses_lowercase_lookup(self):
+        mock_session = MagicMock()
+        first_result = MagicMock()
+        first_result.scalar_one_or_none.return_value = None
+        expected_account = MagicMock()
+        second_result = MagicMock()
+        second_result.scalar_one_or_none.return_value = expected_account
+        mock_session.execute.side_effect = [first_result, second_result]
+
+        result = AccountService.get_account_by_email_with_case_fallback("Case@Test.com", session=mock_session)
+
+        assert result == expected_account
+        assert mock_session.execute.call_count == 2
 
     @pytest.mark.parametrize(
         ("allow_register", "existing_account", "should_create"),
@@ -466,6 +511,35 @@ class TestAccountGeneration:
                     mock_register_service.register.assert_called_once_with(
                         email="test@example.com", name="Test User", password=None, open_id="123", provider="github"
                     )
+                else:
+                    mock_register_service.register.assert_not_called()
+
+    @patch("controllers.console.auth.oauth._get_account_by_openid_or_email", return_value=None)
+    @patch("controllers.console.auth.oauth.FeatureService")
+    @patch("controllers.console.auth.oauth.RegisterService")
+    @patch("controllers.console.auth.oauth.AccountService")
+    @patch("controllers.console.auth.oauth.TenantService")
+    @patch("controllers.console.auth.oauth.db")
+    def test_should_register_with_lowercase_email(
+        self,
+        mock_db,
+        mock_tenant_service,
+        mock_account_service,
+        mock_register_service,
+        mock_feature_service,
+        mock_get_account,
+        app,
+    ):
+        user_info = OAuthUserInfo(id="123", name="Test User", email="Upper@Example.com")
+        mock_feature_service.get_system_features.return_value.is_allow_register = True
+        mock_register_service.register.return_value = MagicMock()
+
+        with app.test_request_context(headers={"Accept-Language": "en-US"}):
+            _generate_account("github", user_info)
+
+        mock_register_service.register.assert_called_once_with(
+            email="upper@example.com", name="Test User", password=None, open_id="123", provider="github"
+        )
 
     @patch("controllers.console.auth.oauth._get_account_by_openid_or_email")
     @patch("controllers.console.auth.oauth.TenantService")
diff --git a/api/tests/unit_tests/controllers/console/auth/test_password_reset.py b/api/tests/unit_tests/controllers/console/auth/test_password_reset.py
index f584952a00..9488cf528e 100644
--- a/api/tests/unit_tests/controllers/console/auth/test_password_reset.py
+++ b/api/tests/unit_tests/controllers/console/auth/test_password_reset.py
@@ -28,6 +28,22 @@ from controllers.console.auth.forgot_password import (
 from controllers.console.error import AccountNotFound, EmailSendIpLimitError
 
 
+@pytest.fixture(autouse=True)
+def _mock_forgot_password_session():
+    with patch("controllers.console.auth.forgot_password.Session") as mock_session_cls:
+        mock_session = MagicMock()
+        mock_session_cls.return_value.__enter__.return_value = mock_session
+        mock_session_cls.return_value.__exit__.return_value = None
+        yield mock_session
+
+
+@pytest.fixture(autouse=True)
+def _mock_forgot_password_db():
+    with patch("controllers.console.auth.forgot_password.db") as mock_db:
+        mock_db.engine = MagicMock()
+        yield mock_db
+
+
 class TestForgotPasswordSendEmailApi:
     """Test cases for sending password reset emails."""
 
@@ -47,20 +63,16 @@ class TestForgotPasswordSendEmailApi:
         return account
 
     @patch("controllers.console.wraps.db")
-    @patch("controllers.console.auth.forgot_password.db")
     @patch("controllers.console.auth.forgot_password.AccountService.is_email_send_ip_limit")
-    @patch("controllers.console.auth.forgot_password.Session")
-    @patch("controllers.console.auth.forgot_password.select")
+    @patch("controllers.console.auth.forgot_password.AccountService.get_account_by_email_with_case_fallback")
     @patch("controllers.console.auth.forgot_password.AccountService.send_reset_password_email")
     @patch("controllers.console.auth.forgot_password.FeatureService.get_system_features")
     def test_send_reset_email_success(
         self,
         mock_get_features,
         mock_send_email,
-        mock_select,
-        mock_session,
+        mock_get_account,
         mock_is_ip_limit,
-        mock_forgot_db,
         mock_wraps_db,
         app,
         mock_account,
@@ -75,11 +87,8 @@ class TestForgotPasswordSendEmailApi:
         """
         # Arrange
         mock_wraps_db.session.query.return_value.first.return_value = MagicMock()
-        mock_forgot_db.engine = MagicMock()
         mock_is_ip_limit.return_value = False
-        mock_session_instance = MagicMock()
-        mock_session_instance.execute.return_value.scalar_one_or_none.return_value = mock_account
-        mock_session.return_value.__enter__.return_value = mock_session_instance
+        mock_get_account.return_value = mock_account
         mock_send_email.return_value = "reset_token_123"
         mock_get_features.return_value.is_allow_register = True
 
@@ -125,20 +134,16 @@ class TestForgotPasswordSendEmailApi:
         ],
     )
     @patch("controllers.console.wraps.db")
-    @patch("controllers.console.auth.forgot_password.db")
     @patch("controllers.console.auth.forgot_password.AccountService.is_email_send_ip_limit")
-    @patch("controllers.console.auth.forgot_password.Session")
-    @patch("controllers.console.auth.forgot_password.select")
+    @patch("controllers.console.auth.forgot_password.AccountService.get_account_by_email_with_case_fallback")
     @patch("controllers.console.auth.forgot_password.AccountService.send_reset_password_email")
     @patch("controllers.console.auth.forgot_password.FeatureService.get_system_features")
     def test_send_reset_email_language_handling(
         self,
         mock_get_features,
         mock_send_email,
-        mock_select,
-        mock_session,
+        mock_get_account,
         mock_is_ip_limit,
-        mock_forgot_db,
         mock_wraps_db,
         app,
         mock_account,
@@ -154,11 +159,8 @@ class TestForgotPasswordSendEmailApi:
         """
         # Arrange
         mock_wraps_db.session.query.return_value.first.return_value = MagicMock()
-        mock_forgot_db.engine = MagicMock()
         mock_is_ip_limit.return_value = False
-        mock_session_instance = MagicMock()
-        mock_session_instance.execute.return_value.scalar_one_or_none.return_value = mock_account
-        mock_session.return_value.__enter__.return_value = mock_session_instance
+        mock_get_account.return_value = mock_account
         mock_send_email.return_value = "token"
         mock_get_features.return_value.is_allow_register = True
 
@@ -229,8 +231,46 @@ class TestForgotPasswordCheckApi:
         assert response["email"] == "test@example.com"
         assert response["token"] == "new_token"
         mock_revoke_token.assert_called_once_with("old_token")
+        mock_generate_token.assert_called_once_with(
+            "test@example.com", code="123456", additional_data={"phase": "reset"}
+        )
         mock_reset_rate_limit.assert_called_once_with("test@example.com")
 
+    @patch("controllers.console.wraps.db")
+    @patch("controllers.console.auth.forgot_password.AccountService.is_forgot_password_error_rate_limit")
+    @patch("controllers.console.auth.forgot_password.AccountService.get_reset_password_data")
+    @patch("controllers.console.auth.forgot_password.AccountService.revoke_reset_password_token")
+    @patch("controllers.console.auth.forgot_password.AccountService.generate_reset_password_token")
+    @patch("controllers.console.auth.forgot_password.AccountService.reset_forgot_password_error_rate_limit")
+    def test_verify_code_preserves_token_email_case(
+        self,
+        mock_reset_rate_limit,
+        mock_generate_token,
+        mock_revoke_token,
+        mock_get_data,
+        mock_is_rate_limit,
+        mock_db,
+        app,
+    ):
+        mock_db.session.query.return_value.first.return_value = MagicMock()
+        mock_is_rate_limit.return_value = False
+        mock_get_data.return_value = {"email": "User@Example.com", "code": "999888"}
+        mock_generate_token.return_value = (None, "fresh-token")
+
+        with app.test_request_context(
+            "/forgot-password/validity",
+            method="POST",
+            json={"email": "user@example.com", "code": "999888", "token": "upper_token"},
+        ):
+            response = ForgotPasswordCheckApi().post()
+
+        assert response == {"is_valid": True, "email": "user@example.com", "token": "fresh-token"}
+        mock_generate_token.assert_called_once_with(
+            "User@Example.com", code="999888", additional_data={"phase": "reset"}
+        )
+        mock_revoke_token.assert_called_once_with("upper_token")
+        mock_reset_rate_limit.assert_called_once_with("user@example.com")
+
     @patch("controllers.console.wraps.db")
     @patch("controllers.console.auth.forgot_password.AccountService.is_forgot_password_error_rate_limit")
     def test_verify_code_rate_limited(self, mock_is_rate_limit, mock_db, app):
@@ -355,20 +395,16 @@ class TestForgotPasswordResetApi:
         return account
 
     @patch("controllers.console.wraps.db")
-    @patch("controllers.console.auth.forgot_password.db")
     @patch("controllers.console.auth.forgot_password.AccountService.get_reset_password_data")
     @patch("controllers.console.auth.forgot_password.AccountService.revoke_reset_password_token")
-    @patch("controllers.console.auth.forgot_password.Session")
-    @patch("controllers.console.auth.forgot_password.select")
+    @patch("controllers.console.auth.forgot_password.AccountService.get_account_by_email_with_case_fallback")
     @patch("controllers.console.auth.forgot_password.TenantService.get_join_tenants")
     def test_reset_password_success(
         self,
         mock_get_tenants,
-        mock_select,
-        mock_session,
+        mock_get_account,
         mock_revoke_token,
         mock_get_data,
-        mock_forgot_db,
         mock_wraps_db,
         app,
         mock_account,
@@ -383,11 +419,8 @@ class TestForgotPasswordResetApi:
         """
         # Arrange
         mock_wraps_db.session.query.return_value.first.return_value = MagicMock()
-        mock_forgot_db.engine = MagicMock()
         mock_get_data.return_value = {"email": "test@example.com", "phase": "reset"}
-        mock_session_instance = MagicMock()
-        mock_session_instance.execute.return_value.scalar_one_or_none.return_value = mock_account
-        mock_session.return_value.__enter__.return_value = mock_session_instance
+        mock_get_account.return_value = mock_account
         mock_get_tenants.return_value = [MagicMock()]
 
         # Act
@@ -475,13 +508,11 @@ class TestForgotPasswordResetApi:
                 api.post()
 
     @patch("controllers.console.wraps.db")
-    @patch("controllers.console.auth.forgot_password.db")
     @patch("controllers.console.auth.forgot_password.AccountService.get_reset_password_data")
     @patch("controllers.console.auth.forgot_password.AccountService.revoke_reset_password_token")
-    @patch("controllers.console.auth.forgot_password.Session")
-    @patch("controllers.console.auth.forgot_password.select")
+    @patch("controllers.console.auth.forgot_password.AccountService.get_account_by_email_with_case_fallback")
     def test_reset_password_account_not_found(
-        self, mock_select, mock_session, mock_revoke_token, mock_get_data, mock_forgot_db, mock_wraps_db, app
+        self, mock_get_account, mock_revoke_token, mock_get_data, mock_wraps_db, app
     ):
         """
         Test password reset for non-existent account.
@@ -491,11 +522,8 @@ class TestForgotPasswordResetApi:
         """
         # Arrange
         mock_wraps_db.session.query.return_value.first.return_value = MagicMock()
-        mock_forgot_db.engine = MagicMock()
         mock_get_data.return_value = {"email": "nonexistent@example.com", "phase": "reset"}
-        mock_session_instance = MagicMock()
-        mock_session_instance.execute.return_value.scalar_one_or_none.return_value = None
-        mock_session.return_value.__enter__.return_value = mock_session_instance
+        mock_get_account.return_value = None
 
         # Act & Assert
         with app.test_request_context(
diff --git a/api/tests/unit_tests/controllers/console/test_setup.py b/api/tests/unit_tests/controllers/console/test_setup.py
new file mode 100644
index 0000000000..e7882dcd2b
--- /dev/null
+++ b/api/tests/unit_tests/controllers/console/test_setup.py
@@ -0,0 +1,39 @@
+from types import SimpleNamespace
+from unittest.mock import patch
+
+from controllers.console.setup import SetupApi
+
+
+class TestSetupApi:
+    def test_post_lowercases_email_before_register(self):
+        """Ensure setup registration normalizes email casing."""
+        payload = {
+            "email": "Admin@Example.com",
+            "name": "Admin User",
+            "password": "ValidPass123!",
+            "language": "en-US",
+        }
+        setup_api = SetupApi(api=None)
+
+        mock_console_ns = SimpleNamespace(payload=payload)
+
+        with (
+            patch("controllers.console.setup.console_ns", mock_console_ns),
+            patch("controllers.console.setup.get_setup_status", return_value=False),
+            patch("controllers.console.setup.TenantService.get_tenant_count", return_value=0),
+            patch("controllers.console.setup.get_init_validate_status", return_value=True),
+            patch("controllers.console.setup.extract_remote_ip", return_value="127.0.0.1"),
+            patch("controllers.console.setup.request", object()),
+            patch("controllers.console.setup.RegisterService.setup") as mock_register,
+        ):
+            response, status = setup_api.post()
+
+        assert response == {"result": "success"}
+        assert status == 201
+        mock_register.assert_called_once_with(
+            email="admin@example.com",
+            name=payload["name"],
+            password=payload["password"],
+            ip_address="127.0.0.1",
+            language=payload["language"],
+        )
diff --git a/api/tests/unit_tests/controllers/console/test_workspace_account.py b/api/tests/unit_tests/controllers/console/test_workspace_account.py
new file mode 100644
index 0000000000..9afc1c4166
--- /dev/null
+++ b/api/tests/unit_tests/controllers/console/test_workspace_account.py
@@ -0,0 +1,247 @@
+from types import SimpleNamespace
+from unittest.mock import MagicMock, patch
+
+import pytest
+from flask import Flask, g
+
+from controllers.console.workspace.account import (
+    AccountDeleteUpdateFeedbackApi,
+    ChangeEmailCheckApi,
+    ChangeEmailResetApi,
+    ChangeEmailSendEmailApi,
+    CheckEmailUnique,
+)
+from models import Account
+from services.account_service import AccountService
+
+
+@pytest.fixture
+def app():
+    app = Flask(__name__)
+    app.config["TESTING"] = True
+    app.config["RESTX_MASK_HEADER"] = "X-Fields"
+    app.login_manager = SimpleNamespace(_load_user=lambda: None)
+    return app
+
+
+def _mock_wraps_db(mock_db):
+    mock_db.session.query.return_value.first.return_value = MagicMock()
+
+
+def _build_account(email: str, account_id: str = "acc", tenant: object | None = None) -> Account:
+    tenant_obj = tenant if tenant is not None else SimpleNamespace(id="tenant-id")
+    account = Account(name=account_id, email=email)
+    account.email = email
+    account.id = account_id
+    account.status = "active"
+    account._current_tenant = tenant_obj
+    return account
+
+
+def _set_logged_in_user(account: Account):
+    g._login_user = account
+    g._current_tenant = account.current_tenant
+
+
+class TestChangeEmailSend:
+    @patch("controllers.console.wraps.db")
+    @patch("controllers.console.workspace.account.current_account_with_tenant")
+    @patch("controllers.console.workspace.account.AccountService.get_change_email_data")
+    @patch("controllers.console.workspace.account.AccountService.send_change_email_email")
+    @patch("controllers.console.workspace.account.AccountService.is_email_send_ip_limit", return_value=False)
+    @patch("controllers.console.workspace.account.extract_remote_ip", return_value="127.0.0.1")
+    @patch("libs.login.check_csrf_token", return_value=None)
+    @patch("controllers.console.wraps.FeatureService.get_system_features")
+    def test_should_normalize_new_email_phase(
+        self,
+        mock_features,
+        mock_csrf,
+        mock_extract_ip,
+        mock_is_ip_limit,
+        mock_send_email,
+        mock_get_change_data,
+        mock_current_account,
+        mock_db,
+        app,
+    ):
+        _mock_wraps_db(mock_db)
+        mock_features.return_value = SimpleNamespace(enable_change_email=True)
+        mock_account = _build_account("current@example.com", "acc1")
+        mock_current_account.return_value = (mock_account, None)
+        mock_get_change_data.return_value = {"email": "current@example.com"}
+        mock_send_email.return_value = "token-abc"
+
+        with app.test_request_context(
+            "/account/change-email",
+            method="POST",
+            json={"email": "New@Example.com", "language": "en-US", "phase": "new_email", "token": "token-123"},
+        ):
+            _set_logged_in_user(_build_account("tester@example.com", "tester"))
+            response = ChangeEmailSendEmailApi().post()
+
+        assert response == {"result": "success", "data": "token-abc"}
+        mock_send_email.assert_called_once_with(
+            account=None,
+            email="new@example.com",
+            old_email="current@example.com",
+            language="en-US",
+            phase="new_email",
+        )
+        mock_extract_ip.assert_called_once()
+        mock_is_ip_limit.assert_called_once_with("127.0.0.1")
+        mock_csrf.assert_called_once()
+
+
+class TestChangeEmailValidity:
+    @patch("controllers.console.wraps.db")
+    @patch("controllers.console.workspace.account.current_account_with_tenant")
+    @patch("controllers.console.workspace.account.AccountService.reset_change_email_error_rate_limit")
+    @patch("controllers.console.workspace.account.AccountService.generate_change_email_token")
+    @patch("controllers.console.workspace.account.AccountService.revoke_change_email_token")
+    @patch("controllers.console.workspace.account.AccountService.add_change_email_error_rate_limit")
+    @patch("controllers.console.workspace.account.AccountService.get_change_email_data")
+    @patch("controllers.console.workspace.account.AccountService.is_change_email_error_rate_limit")
+    @patch("libs.login.check_csrf_token", return_value=None)
+    @patch("controllers.console.wraps.FeatureService.get_system_features")
+    def test_should_validate_with_normalized_email(
+        self,
+        mock_features,
+        mock_csrf,
+        mock_is_rate_limit,
+        mock_get_data,
+        mock_add_rate,
+        mock_revoke_token,
+        mock_generate_token,
+        mock_reset_rate,
+        mock_current_account,
+        mock_db,
+        app,
+    ):
+        _mock_wraps_db(mock_db)
+        mock_features.return_value = SimpleNamespace(enable_change_email=True)
+        mock_account = _build_account("user@example.com", "acc2")
+        mock_current_account.return_value = (mock_account, None)
+        mock_is_rate_limit.return_value = False
+        mock_get_data.return_value = {"email": "user@example.com", "code": "1234", "old_email": "old@example.com"}
+        mock_generate_token.return_value = (None, "new-token")
+
+        with app.test_request_context(
+            "/account/change-email/validity",
+            method="POST",
+            json={"email": "User@Example.com", "code": "1234", "token": "token-123"},
+        ):
+            _set_logged_in_user(_build_account("tester@example.com", "tester"))
+            response = ChangeEmailCheckApi().post()
+
+        assert response == {"is_valid": True, "email": "user@example.com", "token": "new-token"}
+        mock_is_rate_limit.assert_called_once_with("user@example.com")
+        mock_add_rate.assert_not_called()
+        mock_revoke_token.assert_called_once_with("token-123")
+        mock_generate_token.assert_called_once_with(
+            "user@example.com", code="1234", old_email="old@example.com", additional_data={}
+        )
+        mock_reset_rate.assert_called_once_with("user@example.com")
+        mock_csrf.assert_called_once()
+
+
+class TestChangeEmailReset:
+    @patch("controllers.console.wraps.db")
+    @patch("controllers.console.workspace.account.current_account_with_tenant")
+    @patch("controllers.console.workspace.account.AccountService.send_change_email_completed_notify_email")
+    @patch("controllers.console.workspace.account.AccountService.update_account_email")
+    @patch("controllers.console.workspace.account.AccountService.revoke_change_email_token")
+    @patch("controllers.console.workspace.account.AccountService.get_change_email_data")
+    @patch("controllers.console.workspace.account.AccountService.check_email_unique")
+    @patch("controllers.console.workspace.account.AccountService.is_account_in_freeze")
+    @patch("libs.login.check_csrf_token", return_value=None)
+    @patch("controllers.console.wraps.FeatureService.get_system_features")
+    def test_should_normalize_new_email_before_update(
+        self,
+        mock_features,
+        mock_csrf,
+        mock_is_freeze,
+        mock_check_unique,
+        mock_get_data,
+        mock_revoke_token,
+        mock_update_account,
+        mock_send_notify,
+        mock_current_account,
+        mock_db,
+        app,
+    ):
+        _mock_wraps_db(mock_db)
+        mock_features.return_value = SimpleNamespace(enable_change_email=True)
+        current_user = _build_account("old@example.com", "acc3")
+        mock_current_account.return_value = (current_user, None)
+        mock_is_freeze.return_value = False
+        mock_check_unique.return_value = True
+        mock_get_data.return_value = {"old_email": "OLD@example.com"}
+        mock_account_after_update = _build_account("new@example.com", "acc3-updated")
+        mock_update_account.return_value = mock_account_after_update
+
+        with app.test_request_context(
+            "/account/change-email/reset",
+            method="POST",
+            json={"new_email": "New@Example.com", "token": "token-123"},
+        ):
+            _set_logged_in_user(_build_account("tester@example.com", "tester"))
+            ChangeEmailResetApi().post()
+
+            mock_is_freeze.assert_called_once_with("new@example.com")
+            mock_check_unique.assert_called_once_with("new@example.com")
+            mock_revoke_token.assert_called_once_with("token-123")
+            mock_update_account.assert_called_once_with(current_user, email="new@example.com")
+            mock_send_notify.assert_called_once_with(email="new@example.com")
+            mock_csrf.assert_called_once()
+
+
+class TestAccountDeletionFeedback:
+    @patch("controllers.console.wraps.db")
+    @patch("controllers.console.workspace.account.BillingService.update_account_deletion_feedback")
+    def test_should_normalize_feedback_email(self, mock_update, mock_db, app):
+        _mock_wraps_db(mock_db)
+        with app.test_request_context(
+            "/account/delete/feedback",
+            method="POST",
+            json={"email": "User@Example.com", "feedback": "test"},
+        ):
+            response = AccountDeleteUpdateFeedbackApi().post()
+
+        assert response == {"result": "success"}
+        mock_update.assert_called_once_with("User@Example.com", "test")
+
+
+class TestCheckEmailUnique:
+    @patch("controllers.console.wraps.db")
+    @patch("controllers.console.workspace.account.AccountService.check_email_unique")
+    @patch("controllers.console.workspace.account.AccountService.is_account_in_freeze")
+    def test_should_normalize_email(self, mock_is_freeze, mock_check_unique, mock_db, app):
+        _mock_wraps_db(mock_db)
+        mock_is_freeze.return_value = False
+        mock_check_unique.return_value = True
+
+        with app.test_request_context(
+            "/account/change-email/check-email-unique",
+            method="POST",
+            json={"email": "Case@Test.com"},
+        ):
+            response = CheckEmailUnique().post()
+
+        assert response == {"result": "success"}
+        mock_is_freeze.assert_called_once_with("case@test.com")
+        mock_check_unique.assert_called_once_with("case@test.com")
+
+
+def test_get_account_by_email_with_case_fallback_uses_lowercase_lookup():
+    session = MagicMock()
+    first = MagicMock()
+    first.scalar_one_or_none.return_value = None
+    second = MagicMock()
+    expected_account = MagicMock()
+    second.scalar_one_or_none.return_value = expected_account
+    session.execute.side_effect = [first, second]
+
+    result = AccountService.get_account_by_email_with_case_fallback("Mixed@Test.com", session=session)
+
+    assert result is expected_account
+    assert session.execute.call_count == 2
diff --git a/api/tests/unit_tests/controllers/console/test_workspace_members.py b/api/tests/unit_tests/controllers/console/test_workspace_members.py
new file mode 100644
index 0000000000..368892b922
--- /dev/null
+++ b/api/tests/unit_tests/controllers/console/test_workspace_members.py
@@ -0,0 +1,82 @@
+from types import SimpleNamespace
+from unittest.mock import MagicMock, patch
+
+import pytest
+from flask import Flask, g
+
+from controllers.console.workspace.members import MemberInviteEmailApi
+from models.account import Account, TenantAccountRole
+
+
+@pytest.fixture
+def app():
+    flask_app = Flask(__name__)
+    flask_app.config["TESTING"] = True
+    flask_app.login_manager = SimpleNamespace(_load_user=lambda: None)
+    return flask_app
+
+
+def _mock_wraps_db(mock_db):
+    mock_db.session.query.return_value.first.return_value = MagicMock()
+
+
+def _build_feature_flags():
+    placeholder_quota = SimpleNamespace(limit=0, size=0)
+    workspace_members = SimpleNamespace(is_available=lambda count: True)
+    return SimpleNamespace(
+        billing=SimpleNamespace(enabled=False),
+        workspace_members=workspace_members,
+        members=placeholder_quota,
+        apps=placeholder_quota,
+        vector_space=placeholder_quota,
+        documents_upload_quota=placeholder_quota,
+        annotation_quota_limit=placeholder_quota,
+    )
+
+
+class TestMemberInviteEmailApi:
+    @patch("controllers.console.workspace.members.FeatureService.get_features")
+    @patch("controllers.console.workspace.members.RegisterService.invite_new_member")
+    @patch("controllers.console.workspace.members.current_account_with_tenant")
+    @patch("controllers.console.wraps.db")
+    @patch("libs.login.check_csrf_token", return_value=None)
+    def test_invite_normalizes_emails(
+        self,
+        mock_csrf,
+        mock_db,
+        mock_current_account,
+        mock_invite_member,
+        mock_get_features,
+        app,
+    ):
+        _mock_wraps_db(mock_db)
+        mock_get_features.return_value = _build_feature_flags()
+        mock_invite_member.return_value = "token-abc"
+
+        tenant = SimpleNamespace(id="tenant-1", name="Test Tenant")
+        inviter = SimpleNamespace(email="Owner@Example.com", current_tenant=tenant, status="active")
+        mock_current_account.return_value = (inviter, tenant.id)
+
+        with patch("controllers.console.workspace.members.dify_config.CONSOLE_WEB_URL", "https://console.example.com"):
+            with app.test_request_context(
+                "/workspaces/current/members/invite-email",
+                method="POST",
+                json={"emails": ["User@Example.com"], "role": TenantAccountRole.EDITOR.value, "language": "en-US"},
+            ):
+                account = Account(name="tester", email="tester@example.com")
+                account._current_tenant = tenant
+                g._login_user = account
+                g._current_tenant = tenant
+                response, status_code = MemberInviteEmailApi().post()
+
+        assert status_code == 201
+        assert response["invitation_results"][0]["email"] == "user@example.com"
+
+        assert mock_invite_member.call_count == 1
+        call_args = mock_invite_member.call_args
+        assert call_args.kwargs["tenant"] == tenant
+        assert call_args.kwargs["email"] == "User@Example.com"
+        assert call_args.kwargs["language"] == "en-US"
+        assert call_args.kwargs["role"] == TenantAccountRole.EDITOR
+        assert call_args.kwargs["inviter"] == inviter
+        mock_csrf.assert_called_once()
diff --git a/api/tests/unit_tests/controllers/web/test_forgot_password.py b/api/tests/unit_tests/controllers/web/test_forgot_password.py
deleted file mode 100644
index d7c0d24f14..0000000000
--- a/api/tests/unit_tests/controllers/web/test_forgot_password.py
+++ /dev/null
@@ -1,195 +0,0 @@
-"""Unit tests for controllers.web.forgot_password endpoints."""
-
-from __future__ import annotations
-
-import base64
-import builtins
-from types import SimpleNamespace
-from unittest.mock import MagicMock, patch
-
-import pytest
-from flask import Flask
-from flask.views import MethodView
-
-# Ensure flask_restx.api finds MethodView during import.
-if not hasattr(builtins, "MethodView"):
-    builtins.MethodView = MethodView  # type: ignore[attr-defined]
-
-
-def _load_controller_module():
-    """Import controllers.web.forgot_password using a stub package."""
-
-    import importlib
-    import importlib.util
-    import sys
-    from types import ModuleType
-
-    parent_module_name = "controllers.web"
-    module_name = f"{parent_module_name}.forgot_password"
-
-    if parent_module_name not in sys.modules:
-        from flask_restx import Namespace
-
-        stub = ModuleType(parent_module_name)
-        stub.__file__ = "controllers/web/__init__.py"
-        stub.__path__ = ["controllers/web"]
-        stub.__package__ = "controllers"
-        stub.__spec__ = importlib.util.spec_from_loader(parent_module_name, loader=None, is_package=True)
-        stub.web_ns = Namespace("web", description="Web API", path="/")
-        sys.modules[parent_module_name] = stub
-
-    return importlib.import_module(module_name)
-
-
-forgot_password_module = _load_controller_module()
-ForgotPasswordCheckApi = forgot_password_module.ForgotPasswordCheckApi
-ForgotPasswordResetApi = forgot_password_module.ForgotPasswordResetApi
-ForgotPasswordSendEmailApi = forgot_password_module.ForgotPasswordSendEmailApi
-
-
-@pytest.fixture
-def app() -> Flask:
-    """Configure a minimal Flask app for request contexts."""
-
-    app = Flask(__name__)
-    app.config["TESTING"] = True
-    return app
-
-
-@pytest.fixture(autouse=True)
-def _enable_web_endpoint_guards():
-    """Stub enterprise and feature toggles used by route decorators."""
-
-    features = SimpleNamespace(enable_email_password_login=True)
-    with (
-        patch("controllers.console.wraps.dify_config.ENTERPRISE_ENABLED", True),
-        patch("controllers.console.wraps.dify_config.EDITION", "CLOUD"),
-        patch("controllers.console.wraps.FeatureService.get_system_features", return_value=features),
-    ):
-        yield
-
-
-@pytest.fixture(autouse=True)
-def _mock_controller_db():
-    """Replace controller-level db reference with a simple stub."""
-
-    fake_db = SimpleNamespace(engine=MagicMock(name="engine"))
-    fake_wraps_db = SimpleNamespace(
-        session=MagicMock(query=MagicMock(return_value=MagicMock(first=MagicMock(return_value=True))))
-    )
-    with (
-        patch("controllers.web.forgot_password.db", fake_db),
-        patch("controllers.console.wraps.db", fake_wraps_db),
-    ):
-        yield fake_db
-
-
-@patch("controllers.web.forgot_password.AccountService.send_reset_password_email", return_value="reset-token")
-@patch("controllers.web.forgot_password.Session")
-@patch("controllers.web.forgot_password.AccountService.is_email_send_ip_limit", return_value=False)
-@patch("controllers.web.forgot_password.extract_remote_ip", return_value="203.0.113.10")
-def test_send_reset_email_success(
-    mock_extract_ip: MagicMock,
-    mock_is_ip_limit: MagicMock,
-    mock_session: MagicMock,
-    mock_send_email: MagicMock,
-    app: Flask,
-):
-    """POST /forgot-password returns token when email exists and limits allow."""
-
-    mock_account = MagicMock()
-    session_ctx = MagicMock()
-    mock_session.return_value.__enter__.return_value = session_ctx
-    session_ctx.execute.return_value.scalar_one_or_none.return_value = mock_account
-
-    with app.test_request_context(
-        "/forgot-password",
-        method="POST",
-        json={"email": "user@example.com"},
-    ):
-        response = ForgotPasswordSendEmailApi().post()
-
-    assert response == {"result": "success", "data": "reset-token"}
-    mock_extract_ip.assert_called_once()
-    mock_is_ip_limit.assert_called_once_with("203.0.113.10")
-    mock_send_email.assert_called_once_with(account=mock_account, email="user@example.com", language="en-US")
-
-
-@patch("controllers.web.forgot_password.AccountService.reset_forgot_password_error_rate_limit")
-@patch("controllers.web.forgot_password.AccountService.generate_reset_password_token", return_value=({}, "new-token"))
-@patch("controllers.web.forgot_password.AccountService.revoke_reset_password_token")
-@patch("controllers.web.forgot_password.AccountService.get_reset_password_data")
-@patch("controllers.web.forgot_password.AccountService.is_forgot_password_error_rate_limit", return_value=False)
-def test_check_token_success(
-    mock_is_rate_limited: MagicMock,
-    mock_get_data: MagicMock,
-    mock_revoke: MagicMock,
-    mock_generate: MagicMock,
-    mock_reset_limit: MagicMock,
-    app: Flask,
-):
-    """POST /forgot-password/validity validates the code and refreshes token."""
-
-    mock_get_data.return_value = {"email": "user@example.com", "code": "123456"}
-
-    with app.test_request_context(
-        "/forgot-password/validity",
-        method="POST",
-        json={"email": "user@example.com", "code": "123456", "token": "old-token"},
-    ):
-        response = ForgotPasswordCheckApi().post()
-
-    assert response == {"is_valid": True, "email": "user@example.com", "token": "new-token"}
-    mock_is_rate_limited.assert_called_once_with("user@example.com")
-    mock_get_data.assert_called_once_with("old-token")
-    mock_revoke.assert_called_once_with("old-token")
-    mock_generate.assert_called_once_with(
-        "user@example.com",
-        code="123456",
-        additional_data={"phase": "reset"},
-    )
-    mock_reset_limit.assert_called_once_with("user@example.com")
-
-
-@patch("controllers.web.forgot_password.hash_password", return_value=b"hashed-value")
-@patch("controllers.web.forgot_password.secrets.token_bytes", return_value=b"0123456789abcdef")
-@patch("controllers.web.forgot_password.Session")
-@patch("controllers.web.forgot_password.AccountService.revoke_reset_password_token")
-@patch("controllers.web.forgot_password.AccountService.get_reset_password_data")
-def test_reset_password_success(
-    mock_get_data: MagicMock,
-    mock_revoke_token: MagicMock,
-    mock_session: MagicMock,
-    mock_token_bytes: MagicMock,
-    mock_hash_password: MagicMock,
-    app: Flask,
-):
-    """POST /forgot-password/resets updates the stored password when token is valid."""
-
-    mock_get_data.return_value = {"email": "user@example.com", "phase": "reset"}
-    account = MagicMock()
-    session_ctx = MagicMock()
-    mock_session.return_value.__enter__.return_value = session_ctx
-    session_ctx.execute.return_value.scalar_one_or_none.return_value = account
-
-    with app.test_request_context(
-        "/forgot-password/resets",
-        method="POST",
-        json={
-            "token": "reset-token",
-            "new_password": "StrongPass123!",
-            "password_confirm": "StrongPass123!",
-        },
-    ):
-        response = ForgotPasswordResetApi().post()
-
-    assert response == {"result": "success"}
-    mock_get_data.assert_called_once_with("reset-token")
-    mock_revoke_token.assert_called_once_with("reset-token")
-    mock_token_bytes.assert_called_once_with(16)
-    mock_hash_password.assert_called_once_with("StrongPass123!", b"0123456789abcdef")
-    expected_password = base64.b64encode(b"hashed-value").decode()
-    assert account.password == expected_password
-    expected_salt = base64.b64encode(b"0123456789abcdef").decode()
-    assert account.password_salt == expected_salt
-    session_ctx.commit.assert_called_once()
diff --git a/api/tests/unit_tests/controllers/web/test_web_forgot_password.py b/api/tests/unit_tests/controllers/web/test_web_forgot_password.py
new file mode 100644
index 0000000000..3d7c319947
--- /dev/null
+++ b/api/tests/unit_tests/controllers/web/test_web_forgot_password.py
@@ -0,0 +1,226 @@
+import base64
+from types import SimpleNamespace
+from unittest.mock import MagicMock, patch
+
+import pytest
+from flask import Flask
+
+from controllers.web.forgot_password import (
+    ForgotPasswordCheckApi,
+    ForgotPasswordResetApi,
+    ForgotPasswordSendEmailApi,
+)
+
+
+@pytest.fixture
+def app():
+    flask_app = Flask(__name__)
+    flask_app.config["TESTING"] = True
+    return flask_app
+
+
+@pytest.fixture(autouse=True)
+def _patch_wraps():
+    wraps_features = SimpleNamespace(enable_email_password_login=True)
+    dify_settings = SimpleNamespace(ENTERPRISE_ENABLED=True, EDITION="CLOUD")
+    with (
+        patch("controllers.console.wraps.db") as mock_db,
+        patch("controllers.console.wraps.dify_config", dify_settings),
+        patch("controllers.console.wraps.FeatureService.get_system_features", return_value=wraps_features),
+    ):
+        mock_db.session.query.return_value.first.return_value = MagicMock()
+        yield
+
+
+class TestForgotPasswordSendEmailApi:
+    @patch("controllers.web.forgot_password.AccountService.send_reset_password_email")
+    @patch("controllers.web.forgot_password.AccountService.get_account_by_email_with_case_fallback")
+    @patch("controllers.web.forgot_password.AccountService.is_email_send_ip_limit", return_value=False)
+    @patch("controllers.web.forgot_password.extract_remote_ip", return_value="127.0.0.1")
+    @patch("controllers.web.forgot_password.Session")
+    def test_should_normalize_email_before_sending(
+        self,
+        mock_session_cls,
+        mock_extract_ip,
+        mock_rate_limit,
+        mock_get_account,
+        mock_send_mail,
+        app,
+    ):
+        mock_account = MagicMock()
+        mock_get_account.return_value = mock_account
+        mock_send_mail.return_value = "token-123"
+        mock_session = MagicMock()
+        mock_session_cls.return_value.__enter__.return_value = mock_session
+
+        with patch("controllers.web.forgot_password.db", SimpleNamespace(engine="engine")):
+            with app.test_request_context(
+                "/web/forgot-password",
+                method="POST",
+                json={"email": "User@Example.com", "language": "zh-Hans"},
+            ):
+                response = ForgotPasswordSendEmailApi().post()
+
+        assert response == {"result": "success", "data": "token-123"}
+        mock_get_account.assert_called_once_with("User@Example.com", session=mock_session)
+        mock_send_mail.assert_called_once_with(account=mock_account, email="user@example.com", language="zh-Hans")
+        mock_extract_ip.assert_called_once()
+        mock_rate_limit.assert_called_once_with("127.0.0.1")
+
+
+class TestForgotPasswordCheckApi:
+    @patch("controllers.web.forgot_password.AccountService.reset_forgot_password_error_rate_limit")
+    @patch("controllers.web.forgot_password.AccountService.generate_reset_password_token")
+    @patch("controllers.web.forgot_password.AccountService.revoke_reset_password_token")
+    @patch("controllers.web.forgot_password.AccountService.add_forgot_password_error_rate_limit")
+    @patch("controllers.web.forgot_password.AccountService.get_reset_password_data")
+    @patch("controllers.web.forgot_password.AccountService.is_forgot_password_error_rate_limit")
+    def test_should_normalize_email_for_validity_checks(
+        self,
+        mock_is_rate_limit,
+        mock_get_data,
+        mock_add_rate,
+        mock_revoke_token,
+        mock_generate_token,
+        mock_reset_rate,
+        app,
+    ):
+        mock_is_rate_limit.return_value = False
+        mock_get_data.return_value = {"email": "User@Example.com", "code": "1234"}
+        mock_generate_token.return_value = (None, "new-token")
+
+        with app.test_request_context(
+            "/web/forgot-password/validity",
+            method="POST",
+            json={"email": "User@Example.com", "code": "1234", "token": "token-123"},
+        ):
+            response = ForgotPasswordCheckApi().post()
+
+        assert response == {"is_valid": True, "email": "user@example.com", "token": "new-token"}
+        mock_is_rate_limit.assert_called_once_with("user@example.com")
+        mock_add_rate.assert_not_called()
+        mock_revoke_token.assert_called_once_with("token-123")
+        mock_generate_token.assert_called_once_with(
+            "User@Example.com",
+            code="1234",
+            additional_data={"phase": "reset"},
+        )
+        mock_reset_rate.assert_called_once_with("user@example.com")
+
+    @patch("controllers.web.forgot_password.AccountService.reset_forgot_password_error_rate_limit")
+    @patch("controllers.web.forgot_password.AccountService.generate_reset_password_token")
+    @patch("controllers.web.forgot_password.AccountService.revoke_reset_password_token")
+    @patch("controllers.web.forgot_password.AccountService.get_reset_password_data")
+    @patch("controllers.web.forgot_password.AccountService.is_forgot_password_error_rate_limit")
+    def test_should_preserve_token_email_case(
+        self,
+        mock_is_rate_limit,
+        mock_get_data,
+        mock_revoke_token,
+        mock_generate_token,
+        mock_reset_rate,
+        app,
+    ):
+        mock_is_rate_limit.return_value = False
+        mock_get_data.return_value = {"email": "MixedCase@Example.com", "code": "5678"}
+        mock_generate_token.return_value = (None, "fresh-token")
+
+        with app.test_request_context(
+            "/web/forgot-password/validity",
+            method="POST",
+            json={"email": "mixedcase@example.com", "code": "5678", "token": "token-upper"},
+        ):
+            response = ForgotPasswordCheckApi().post()
+
+        assert response == {"is_valid": True, "email": "mixedcase@example.com", "token": "fresh-token"}
+        mock_generate_token.assert_called_once_with(
+            "MixedCase@Example.com",
+            code="5678",
+            additional_data={"phase": "reset"},
+        )
+        mock_revoke_token.assert_called_once_with("token-upper")
+        mock_reset_rate.assert_called_once_with("mixedcase@example.com")
+
+
+class TestForgotPasswordResetApi:
+    @patch("controllers.web.forgot_password.ForgotPasswordResetApi._update_existing_account")
+    @patch("controllers.web.forgot_password.AccountService.get_account_by_email_with_case_fallback")
+    @patch("controllers.web.forgot_password.Session")
+    @patch("controllers.web.forgot_password.AccountService.revoke_reset_password_token")
+    @patch("controllers.web.forgot_password.AccountService.get_reset_password_data")
+    def test_should_fetch_account_with_fallback(
+        self,
+        mock_get_reset_data,
+        mock_revoke_token,
+        mock_session_cls,
+        mock_get_account,
+        mock_update_account,
+        app,
+    ):
+        mock_get_reset_data.return_value = {"phase": "reset", "email": "User@Example.com", "code": "1234"}
+        mock_account = MagicMock()
+        mock_get_account.return_value = mock_account
+        mock_session = MagicMock()
+        mock_session_cls.return_value.__enter__.return_value = mock_session
+
+        with patch("controllers.web.forgot_password.db", SimpleNamespace(engine="engine")):
+            with app.test_request_context(
+                "/web/forgot-password/resets",
+                method="POST",
+                json={
+                    "token": "token-123",
+                    "new_password": "ValidPass123!",
+                    "password_confirm": "ValidPass123!",
+                },
+            ):
+                response = ForgotPasswordResetApi().post()
+
+        assert response == {"result": "success"}
+        mock_get_account.assert_called_once_with("User@Example.com", session=mock_session)
+        mock_update_account.assert_called_once()
+        mock_revoke_token.assert_called_once_with("token-123")
+
+    @patch("controllers.web.forgot_password.hash_password", return_value=b"hashed-value")
+    @patch("controllers.web.forgot_password.secrets.token_bytes", return_value=b"0123456789abcdef")
+    @patch("controllers.web.forgot_password.Session")
+    @patch("controllers.web.forgot_password.AccountService.revoke_reset_password_token")
+    @patch("controllers.web.forgot_password.AccountService.get_reset_password_data")
+    @patch("controllers.web.forgot_password.AccountService.get_account_by_email_with_case_fallback")
+    def test_should_update_password_and_commit(
+        self,
+        mock_get_account,
+        mock_get_reset_data,
+        mock_revoke_token,
+        mock_session_cls,
+        mock_token_bytes,
+        mock_hash_password,
+        app,
+    ):
+        mock_get_reset_data.return_value = {"phase": "reset", "email": "user@example.com"}
+        account = MagicMock()
+        mock_get_account.return_value = account
+        mock_session = MagicMock()
+        mock_session_cls.return_value.__enter__.return_value = mock_session
+
+        with patch("controllers.web.forgot_password.db", SimpleNamespace(engine="engine")):
+            with app.test_request_context(
+                "/web/forgot-password/resets",
+                method="POST",
+                json={
+                    "token": "reset-token",
+                    "new_password": "StrongPass123!",
+                    "password_confirm": "StrongPass123!",
+                },
+            ):
+                response = ForgotPasswordResetApi().post()
+
+        assert response == {"result": "success"}
+        mock_get_reset_data.assert_called_once_with("reset-token")
+        mock_revoke_token.assert_called_once_with("reset-token")
+        mock_token_bytes.assert_called_once_with(16)
+        mock_hash_password.assert_called_once_with("StrongPass123!", b"0123456789abcdef")
+        expected_password = base64.b64encode(b"hashed-value").decode()
+        assert account.password == expected_password
+        expected_salt = base64.b64encode(b"0123456789abcdef").decode()
+        assert account.password_salt == expected_salt
+        mock_session.commit.assert_called_once()
diff --git a/api/tests/unit_tests/controllers/web/test_web_login.py b/api/tests/unit_tests/controllers/web/test_web_login.py
new file mode 100644
index 0000000000..e62993e8d5
--- /dev/null
+++ b/api/tests/unit_tests/controllers/web/test_web_login.py
@@ -0,0 +1,91 @@
+import base64
+from types import SimpleNamespace
+from unittest.mock import MagicMock, patch
+
+import pytest
+from flask import Flask
+
+from controllers.web.login import EmailCodeLoginApi, EmailCodeLoginSendEmailApi
+
+
+def encode_code(code: str) -> str:
+    return base64.b64encode(code.encode("utf-8")).decode()
+
+
+@pytest.fixture
+def app():
+    flask_app = Flask(__name__)
+    flask_app.config["TESTING"] = True
+    return flask_app
+
+
+@pytest.fixture(autouse=True)
+def _patch_wraps():
+    wraps_features = SimpleNamespace(enable_email_password_login=True)
+    console_dify = SimpleNamespace(ENTERPRISE_ENABLED=True, EDITION="CLOUD")
+    web_dify = SimpleNamespace(ENTERPRISE_ENABLED=True)
+    with (
+        patch("controllers.console.wraps.db") as mock_db,
+        patch("controllers.console.wraps.dify_config", console_dify),
+        patch("controllers.console.wraps.FeatureService.get_system_features", return_value=wraps_features),
+        patch("controllers.web.login.dify_config", web_dify),
+    ):
+        mock_db.session.query.return_value.first.return_value = MagicMock()
+        yield
+
+
+class TestEmailCodeLoginSendEmailApi:
+    @patch("controllers.web.login.WebAppAuthService.send_email_code_login_email")
+    @patch("controllers.web.login.WebAppAuthService.get_user_through_email")
+    def test_should_fetch_account_with_original_email(
+        self,
+        mock_get_user,
+        mock_send_email,
+        app,
+    ):
+        mock_account = MagicMock()
+        mock_get_user.return_value = mock_account
+        mock_send_email.return_value = "token-123"
+
+        with app.test_request_context(
+            "/web/email-code-login",
+            method="POST",
+            json={"email": "User@Example.com", "language": "en-US"},
+        ):
+            response = EmailCodeLoginSendEmailApi().post()
+
+        assert response == {"result": "success", "data": "token-123"}
+        mock_get_user.assert_called_once_with("User@Example.com")
+        mock_send_email.assert_called_once_with(account=mock_account, language="en-US")
+
+
+class TestEmailCodeLoginApi:
+    @patch("controllers.web.login.AccountService.reset_login_error_rate_limit")
+    @patch("controllers.web.login.WebAppAuthService.login", return_value="new-access-token")
+    @patch("controllers.web.login.WebAppAuthService.get_user_through_email")
+    @patch("controllers.web.login.WebAppAuthService.revoke_email_code_login_token")
+    @patch("controllers.web.login.WebAppAuthService.get_email_code_login_data")
+    def test_should_normalize_email_before_validating(
+        self,
+        mock_get_token_data,
+        mock_revoke_token,
+        mock_get_user,
+        mock_login,
+        mock_reset_login_rate,
+        app,
+    ):
+        mock_get_token_data.return_value = {"email": "User@Example.com", "code": "123456"}
+        mock_get_user.return_value = MagicMock()
+
+        with app.test_request_context(
+            "/web/email-code-login/validity",
+            method="POST",
+            json={"email": "User@Example.com", "code": encode_code("123456"), "token": "token-123"},
+        ):
+            response = EmailCodeLoginApi().post()
+
+        assert response.get_json() == {"result": "success", "data": {"access_token": "new-access-token"}}
+        mock_get_user.assert_called_once_with("User@Example.com")
+        mock_revoke_token.assert_called_once_with("token-123")
+        mock_login.assert_called_once()
+        mock_reset_login_rate.assert_called_once_with("user@example.com")
diff --git a/api/tests/unit_tests/services/test_account_service.py b/api/tests/unit_tests/services/test_account_service.py
index e35ba74c56..8ae20f35d8 100644
--- a/api/tests/unit_tests/services/test_account_service.py
+++ b/api/tests/unit_tests/services/test_account_service.py
@@ -5,7 +5,7 @@ from unittest.mock import MagicMock, patch
 import pytest
 
 from configs import dify_config
-from models.account import Account
+from models.account import Account, AccountStatus
 from services.account_service import AccountService, RegisterService, TenantService
 from services.errors.account import (
     AccountAlreadyInTenantError,
@@ -1147,9 +1147,13 @@ class TestRegisterService:
         mock_session = MagicMock()
         mock_session.query.return_value.filter_by.return_value.first.return_value = None  # No existing account
 
-        with patch("services.account_service.Session") as mock_session_class:
+        with (
+            patch("services.account_service.Session") as mock_session_class,
+            patch("services.account_service.AccountService.get_account_by_email_with_case_fallback") as mock_lookup,
+        ):
             mock_session_class.return_value.__enter__.return_value = mock_session
             mock_session_class.return_value.__exit__.return_value = None
+            mock_lookup.return_value = None
 
             # Mock RegisterService.register
             mock_new_account = TestAccountAssociatedDataFactory.create_account_mock(
@@ -1182,9 +1186,59 @@ class TestRegisterService:
                         email="newuser@example.com",
                         name="newuser",
                         language="en-US",
-                        status="pending",
+                        status=AccountStatus.PENDING,
                         is_setup=True,
                     )
+                    mock_lookup.assert_called_once_with("newuser@example.com", session=mock_session)
+
+    def test_invite_new_member_normalizes_new_account_email(
+        self, mock_db_dependencies, mock_redis_dependencies, mock_task_dependencies
+    ):
+        """Ensure inviting with mixed-case email normalizes before registering."""
+        mock_tenant = MagicMock()
+        mock_tenant.id = "tenant-456"
+        mock_inviter = TestAccountAssociatedDataFactory.create_account_mock(account_id="inviter-123", name="Inviter")
+        mixed_email = "Invitee@Example.com"
+
+        mock_session = MagicMock()
+        with (
+            patch("services.account_service.Session") as mock_session_class,
+            patch("services.account_service.AccountService.get_account_by_email_with_case_fallback") as mock_lookup,
+        ):
+            mock_session_class.return_value.__enter__.return_value = mock_session
+            mock_session_class.return_value.__exit__.return_value = None
+            mock_lookup.return_value = None
+
+            mock_new_account = TestAccountAssociatedDataFactory.create_account_mock(
+                account_id="new-user-789", email="invitee@example.com", name="invitee", status="pending"
+            )
+            with patch("services.account_service.RegisterService.register") as mock_register:
+                mock_register.return_value = mock_new_account
+                with (
+                    patch("services.account_service.TenantService.check_member_permission") as mock_check_permission,
+                    patch("services.account_service.TenantService.create_tenant_member") as mock_create_member,
+                    patch("services.account_service.TenantService.switch_tenant") as mock_switch_tenant,
+                    patch("services.account_service.RegisterService.generate_invite_token") as mock_generate_token,
+                ):
+                    mock_generate_token.return_value = "invite-token-abc"
+
+                    RegisterService.invite_new_member(
+                        tenant=mock_tenant,
+                        email=mixed_email,
+                        language="en-US",
+                        role="normal",
+                        inviter=mock_inviter,
+                    )
+
+                    mock_register.assert_called_once_with(
+                        email="invitee@example.com",
+                        name="invitee",
+                        language="en-US",
+                        status=AccountStatus.PENDING,
+                        is_setup=True,
+                    )
+                    mock_lookup.assert_called_once_with(mixed_email, session=mock_session)
+                    mock_check_permission.assert_called_once_with(mock_tenant, mock_inviter, None, "add")
                     mock_create_member.assert_called_once_with(mock_tenant, mock_new_account, "normal")
                     mock_switch_tenant.assert_called_once_with(mock_new_account, mock_tenant.id)
                     mock_generate_token.assert_called_once_with(mock_tenant, mock_new_account)
@@ -1207,9 +1261,13 @@ class TestRegisterService:
         mock_session = MagicMock()
         mock_session.query.return_value.filter_by.return_value.first.return_value = mock_existing_account
 
-        with patch("services.account_service.Session") as mock_session_class:
+        with (
+            patch("services.account_service.Session") as mock_session_class,
+            patch("services.account_service.AccountService.get_account_by_email_with_case_fallback") as mock_lookup,
+        ):
             mock_session_class.return_value.__enter__.return_value = mock_session
             mock_session_class.return_value.__exit__.return_value = None
+            mock_lookup.return_value = mock_existing_account
 
             # Mock the db.session.query for TenantAccountJoin
             mock_db_query = MagicMock()
@@ -1238,6 +1296,7 @@ class TestRegisterService:
                 mock_create_member.assert_called_once_with(mock_tenant, mock_existing_account, "normal")
                 mock_generate_token.assert_called_once_with(mock_tenant, mock_existing_account)
                 mock_task_dependencies.delay.assert_called_once()
+                mock_lookup.assert_called_once_with("existing@example.com", session=mock_session)
 
     def test_invite_new_member_already_in_tenant(self, mock_db_dependencies, mock_redis_dependencies):
         """Test inviting a member who is already in the tenant."""
@@ -1251,7 +1310,6 @@ class TestRegisterService:
 
         # Mock database queries
         query_results = {
-            ("Account", "email", "existing@example.com"): mock_existing_account,
             (
                 "TenantAccountJoin",
                 "tenant_id",
@@ -1261,7 +1319,11 @@ class TestRegisterService:
         ServiceDbTestHelper.setup_db_query_filter_by_mock(mock_db_dependencies["db"], query_results)
 
         # Mock TenantService methods
-        with patch("services.account_service.TenantService.check_member_permission") as mock_check_permission:
+        with (
+            patch("services.account_service.AccountService.get_account_by_email_with_case_fallback") as mock_lookup,
+            patch("services.account_service.TenantService.check_member_permission") as mock_check_permission,
+        ):
+            mock_lookup.return_value = mock_existing_account
             # Execute test and verify exception
             self._assert_exception_raised(
                 AccountAlreadyInTenantError,
@@ -1272,6 +1334,7 @@ class TestRegisterService:
                 role="normal",
                 inviter=mock_inviter,
             )
+            mock_lookup.assert_called_once()
 
     def test_invite_new_member_no_inviter(self):
         """Test inviting a member without providing an inviter."""
@@ -1497,6 +1560,30 @@ class TestRegisterService:
         # Verify results
         assert result is None
 
+    def test_get_invitation_with_case_fallback_returns_initial_match(self):
+        """Fallback helper should return the initial invitation when present."""
+        invitation = {"workspace_id": "tenant-456"}
+        with patch(
+            "services.account_service.RegisterService.get_invitation_if_token_valid", return_value=invitation
+        ) as mock_get:
+            result = RegisterService.get_invitation_with_case_fallback("tenant-456", "User@Test.com", "token-123")
+
+        assert result == invitation
+        mock_get.assert_called_once_with("tenant-456", "User@Test.com", "token-123")
+
+    def test_get_invitation_with_case_fallback_retries_with_lowercase(self):
+        """Fallback helper should retry with lowercase email when needed."""
+        invitation = {"workspace_id": "tenant-456"}
+        with patch("services.account_service.RegisterService.get_invitation_if_token_valid") as mock_get:
+            mock_get.side_effect = [None, invitation]
+            result = RegisterService.get_invitation_with_case_fallback("tenant-456", "User@Test.com", "token-123")
+
+        assert result == invitation
+        assert mock_get.call_args_list == [
+            (("tenant-456", "User@Test.com", "token-123"),),
+            (("tenant-456", "user@test.com", "token-123"),),
+        ]
+
     # ==================== Helper Method Tests ====================
 
     def test_get_invitation_token_key(self):