diff --git a/web/app/components/base/avatar/index.tsx b/web/app/components/base/avatar/index.tsx
index 2a08f75f7b..85a024cbbf 100644
--- a/web/app/components/base/avatar/index.tsx
+++ b/web/app/components/base/avatar/index.tsx
@@ -8,6 +8,7 @@ export type AvatarProps = {
   size?: number
   className?: string
   textClassName?: string
+  backgroundColor?: string
 }
 const Avatar = ({
   name,
@@ -15,9 +16,18 @@ const Avatar = ({
   size = 30,
   className,
   textClassName,
+  backgroundColor,
 }: AvatarProps) => {
-  const avatarClassName = 'shrink-0 flex items-center rounded-full bg-primary-600'
-  const style = { width: `${size}px`, height: `${size}px`, fontSize: `${size}px`, lineHeight: `${size}px` }
+  const avatarClassName = backgroundColor
+    ? 'shrink-0 flex items-center rounded-full'
+    : 'shrink-0 flex items-center rounded-full bg-primary-600'
+  const style = {
+    width: `${size}px`,
+    height: `${size}px`,
+    fontSize: `${size}px`,
+    lineHeight: `${size}px`,
+    ...(backgroundColor && !avatar ? { backgroundColor } : {}),
+  }
   const [imgError, setImgError] = useState(false)
 
   const handleError = () => {
diff --git a/web/app/components/workflow/header/online-users.tsx b/web/app/components/workflow/header/online-users.tsx
index 4d868cf57f..a48ae40934 100644
--- a/web/app/components/workflow/header/online-users.tsx
+++ b/web/app/components/workflow/header/online-users.tsx
@@ -3,6 +3,16 @@ import Avatar from '@/app/components/base/avatar'
 import { useCollaboration } from '../collaboration/hooks/use-collaboration'
 import { useStore } from '../store'
 import cn from '@/utils/classnames'
+import { ChevronDown } from '@/app/components/base/icons/src/vender/solid/arrows'
+
+const getUserColor = (id: string) => {
+  const colors = ['#3B82F6', '#EF4444', '#10B981', '#F59E0B', '#8B5CF6', '#EC4899', '#06B6D4', '#84CC16']
+  const hash = id.split('').reduce((a, b) => {
+    a = ((a << 5) - a) + b.charCodeAt(0)
+    return a & a
+  }, 0)
+  return colors[Math.abs(hash) % colors.length]
+}
 
 const OnlineUsers = () => {
   const appId = useStore(s => s.appId)
@@ -11,38 +21,53 @@ const OnlineUsers = () => {
   if (!onlineUsers || onlineUsers.length === 0)
     return null
 
-  // Show max 2 avatars directly, rest as count
-  const visibleUsers = onlineUsers.slice(0, 2)
-  const remainingCount = onlineUsers.length - 2
+  // Display logic:
+  // 1-3 users: show all avatars
+  // 4+ users: show 2 avatars + count + arrow
+  const shouldShowCount = onlineUsers.length >= 4
+  const maxVisible = shouldShowCount ? 2 : 3
+  const visibleUsers = onlineUsers.slice(0, maxVisible)
+  const remainingCount = onlineUsers.length - maxVisible
 
   return (
-    <div className="flex items-center -space-x-2">
-      {visibleUsers.map((user, index) => (
-        <div
-          key={`${user.sid}-${index}`}
-          className="relative"
-          style={{ zIndex: visibleUsers.length - index }}
-        >
-          <Avatar
-            name={user.username || 'User'}
-            avatar={user.avatar}
-            size={28}
-            className="ring-2 ring-white"
-          />
-        </div>
-      ))}
-      {remainingCount > 0 && (
-        <div
-          className={cn(
-            'flex items-center justify-center',
-            'h-7 w-7 rounded-full bg-gray-300',
-            'text-xs font-medium text-gray-700',
-            'ring-2 ring-white',
+    <div className="flex items-center rounded-full bg-white px-1 py-1">
+      <div className="flex items-center">
+        <div className="flex items-center -space-x-2">
+          {visibleUsers.map((user, index) => {
+            const userColor = getUserColor(user.user_id)
+            return (
+              <div
+                key={`${user.sid}-${index}`}
+                className="relative"
+                style={{ zIndex: visibleUsers.length - index }}
+              >
+                <Avatar
+                  name={user.username || 'User'}
+                  avatar={user.avatar}
+                  size={28}
+                  className="ring-2 ring-white"
+                  backgroundColor={userColor}
+                />
+              </div>
+            )
+          })}
+          {remainingCount > 0 && (
+            <div
+              className={cn(
+                'flex h-7 w-7 items-center justify-center',
+                'rounded-full bg-gray-300',
+                'text-xs font-medium text-gray-700',
+                'ring-2 ring-white',
+              )}
+            >
+              +{remainingCount}
+            </div>
           )}
-        >
-          +{remainingCount}
         </div>
-      )}
+        {remainingCount > 0 && (
+          <ChevronDown className="ml-1 h-3 w-3 text-gray-500" />
+        )}
+      </div>
     </div>
   )
 }