Add presence indicators and a manual "appear offline" override (#36)

Every avatar in the app (chat messages, room member list, your own
avatar in the top bar/profile, the admin user list, the room-invite
search) now shows a green/red presence dot. Also adds a global
"Appear offline" toggle in the account menu, letting a user lurk in a
room undetected -- it overrides the real connection state everywhere,
not per-room.

Backend: new GlobalPresence (backend/app/ws/global_presence.py), a
cross-instance Redis-backed connection tracker parallel to the
existing per-room Presence, incremented/decremented on WS connect/
disconnect. A new users.appear_offline column (migration
f0f6e494454a) always wins over actual connection state when computing
displayed status. RoomMemberRead gained a computed `status` field;
add_member/change_member_role/list_room_members all compute it via a
shared _member_status() helper. Connect/disconnect and profile
updates (display_name, avatar, appear_offline) all broadcast
member_updated to every room the user belongs to, reusing the
broadcast infrastructure from the earlier avatar-staleness fix, so
chat surfaces update live with no new WS envelope type needed. A new
GET /api/users/online gives the admin list and user-search a snapshot
(deliberately not live -- see backend/app/routers/users.py) for
surfaces where "accurate as of page load" is good enough.

Frontend: UserAvatar renders an optional status dot; every call site
threads status/appear_offline through from whichever data source it
already has (room members, the current user, or the new online-ids
snapshot for admin/search).

4 new backend tests (backend/tests/test_presence.py); existing
broadcast-adjacent WS tests updated to tolerate the new member_updated
noise on connect. Verified end-to-end in the browser with two real
users: presence dot flips live on connect/disconnect via the existing
room-broadcast channel, and the lurk toggle correctly forces offline
while still connected.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

backend/alembic/versions/f0f6e494454a_user_appear_offline_presence_override.py

@@ -0,0 +1,32 @@
+"""user appear_offline presence override
+
+Revision ID: f0f6e494454a
+Revises: e849b2efb79b
+Create Date: 2026-08-16 15:04:50.204291
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = 'f0f6e494454a'
+down_revision: Union[str, Sequence[str], None] = 'e849b2efb79b'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('users', sa.Column('appear_offline', sa.Boolean(), server_default='false', nullable=False))
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column('users', 'appear_offline')
+    # ### end Alembic commands ###

backend/app/main.py

@@ -15,6 +15,7 @@ from app.routers import admin, auth, bots, health, push, rooms, signup, uploads,
 from app.ws.broadcaster import Broadcaster
 from app.ws.chat import router as ws_router
 from app.ws.connection_manager import ConnectionManager
+from app.ws.global_presence import GlobalPresence
 from app.ws.presence import Presence
 
 # backend/app/main.py -> backend/ -> repo root -- matches both the local
@@ -68,6 +69,7 @@ def create_app() -> FastAPI:
     app.state.connection_manager = ConnectionManager()
     app.state.redis = Redis.from_url(settings.redis_url, decode_responses=True)
     app.state.presence = Presence(app.state.redis)
+    app.state.global_presence = GlobalPresence(app.state.redis)
     app.state.broadcaster = Broadcaster(app.state.redis, app.state.connection_manager)
 
     app.include_router(health.router)

backend/app/models/user.py

@@ -21,6 +21,10 @@ class User(Base):
     theme: Mapped[str | None] = mapped_column(String(20))
     avatar_filename: Mapped[str | None] = mapped_column(String(64))
     avatar_content_type: Mapped[str | None] = mapped_column(String(50))
+    # Manual override for the presence indicator -- when set, this user
+    # always shows as offline to everyone regardless of actual connection
+    # state (a "lurk" mode), independent of any individual room.
+    appear_offline: Mapped[bool] = mapped_column(Boolean, default=False, server_default="false", nullable=False)
     created_at: Mapped[datetime] = mapped_column(
         DateTime(timezone=True), server_default=func.now(), nullable=False
     )

backend/app/routers/auth.py

@@ -85,11 +85,13 @@ async def update_profile(
         current_user.display_name = display_name or None
     if "theme" in updates:
         current_user.theme = updates["theme"]
+    if "appear_offline" in updates:
+        current_user.appear_offline = updates["appear_offline"]
     await db.commit()
     await db.refresh(current_user)
     # theme is private to this user, not shown to anyone else -- only
     # broadcast when something other members would actually see changed.
-    if "display_name" in updates:
+    if "display_name" in updates or "appear_offline" in updates:
         await broadcast_member_updated(db, request.app.state.broadcaster, current_user.id)
     return current_user
 

backend/app/routers/rooms.py

@@ -201,14 +201,24 @@ async def leave_room_endpoint(
         raise HTTPException(status_code=404, detail="Not a member of this room")
 
 
+def _member_status(user: User, online_ids: set[uuid.UUID]) -> str:
+    # appear_offline always wins, regardless of actual connection -- that's
+    # the whole point of the override (lurking in a room undetected).
+    return "offline" if user.appear_offline or user.id not in online_ids else "online"
+
+
 @router.get("/{room_id}/members", response_model=list[RoomMemberRead])
 async def list_room_members_endpoint(
+    request: Request,
     room_id: uuid.UUID,
     current_user: User = Depends(get_current_user),
     db: AsyncSession = Depends(get_db),
 ):
     await require_room_member(room_id, current_user, db)
     memberships = await list_room_members(db, room_id)
+    online_ids = await request.app.state.global_presence.online_user_ids(
+        [m.user_id for m in memberships]
+    )
     return [
         RoomMemberRead(
             user_id=m.user_id,
@@ -217,6 +227,7 @@ async def list_room_members_endpoint(
             avatar_filename=m.user.avatar_filename,
             role=m.role,
             joined_at=m.joined_at,
+            status=_member_status(m.user, online_ids),
         )
         for m in memberships
     ]
@@ -244,6 +255,7 @@ async def remove_member_endpoint(
 
 @router.patch("/{room_id}/members/{user_id}", response_model=RoomMemberRead)
 async def change_member_role_endpoint(
+    request: Request,
     room_id: uuid.UUID,
     user_id: uuid.UUID,
     data: RoomMemberRoleUpdate,
@@ -259,6 +271,7 @@ async def change_member_role_endpoint(
         raise HTTPException(
             status_code=400, detail="Use transfer-ownership to change the room owner"
         )
+    online_ids = await request.app.state.global_presence.online_user_ids([membership.user_id])
     return RoomMemberRead(
         user_id=membership.user_id,
         username=membership.user.username,
@@ -266,6 +279,7 @@ async def change_member_role_endpoint(
         avatar_filename=membership.user.avatar_filename,
         role=membership.role,
         joined_at=membership.joined_at,
+        status=_member_status(membership.user, online_ids),
     )
 
 
@@ -468,6 +482,7 @@ async def add_member_endpoint(
     except AlreadyMemberError:
         raise HTTPException(status_code=409, detail="That user is already a member")
     await broadcast_room_added(request.app.state.broadcaster, data.user_id, room)
+    online_ids = await request.app.state.global_presence.online_user_ids([membership.user_id])
     return RoomMemberRead(
         user_id=membership.user_id,
         username=membership.user.username,
@@ -475,6 +490,7 @@ async def add_member_endpoint(
         avatar_filename=membership.user.avatar_filename,
         role=membership.role,
         joined_at=membership.joined_at,
+        status=_member_status(membership.user, online_ids),
     )
 
 

backend/app/routers/users.py

@@ -1,6 +1,6 @@
 import uuid
 
-from fastapi import APIRouter, Depends, HTTPException
+from fastapi import APIRouter, Depends, HTTPException, Request
 from fastapi.responses import FileResponse
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
@@ -27,6 +27,25 @@ async def list_users_directory_endpoint(
     return list(result.scalars().all())
 
 
+@router.get("/online", response_model=list[uuid.UUID])
+async def list_online_users_endpoint(
+    request: Request,
+    current_user: User = Depends(get_current_user),
+    db: AsyncSession = Depends(get_db),
+) -> list[uuid.UUID]:
+    """A snapshot, not a live feed -- deliberately simpler than the presence
+    dot in chat (which updates live via the existing room-broadcast
+    machinery). Used by surfaces where "accurate as of page load" is good
+    enough: the admin user list and the room-invite user search."""
+    raw_online_ids = await request.app.state.global_presence.all_online_user_ids()
+    if not raw_online_ids:
+        return []
+    result = await db.execute(
+        select(User.id).where(User.id.in_(raw_online_ids), User.appear_offline.is_(False))
+    )
+    return [row[0] for row in result.all()]
+
+
 @router.get("/{user_id}/avatar")
 async def get_user_avatar_endpoint(
     user_id: uuid.UUID,

backend/app/schemas/room.py

@@ -1,5 +1,6 @@
 import uuid
 from datetime import datetime
+from typing import Literal
 
 from pydantic import BaseModel, ConfigDict, Field
 
@@ -43,6 +44,10 @@ class RoomMemberRead(BaseModel):
     avatar_filename: str | None
     role: RoomRole
     joined_at: datetime
+    # "offline" whenever the user has set appear_offline, regardless of
+    # actual connection -- computed by the router (needs GlobalPresence),
+    # not derivable from the model alone.
+    status: Literal["online", "offline"]
 
 
 class RoomMemberAdd(BaseModel):

backend/app/schemas/user.py

@@ -22,17 +22,20 @@ class UserRead(BaseModel):
     display_name: str | None
     theme: str | None
     avatar_filename: str | None
+    appear_offline: bool
     created_at: datetime
 
 
 class ProfileUpdate(BaseModel):
-    # Both fields are independently optional-and-settable -- the router
-    # only applies keys actually present in the request body
+    # Each field is independently optional-and-settable -- the router only
+    # applies keys actually present in the request body
     # (model_dump(exclude_unset=True)), so a call that only wants to change
-    # the theme doesn't clobber display_name back to None, and vice versa.
+    # the theme doesn't clobber display_name (or appear_offline) back to
+    # their defaults, and vice versa.
     display_name: str | None = Field(default=None, max_length=50)
     # Kept in sync with frontend/src/styles/themes.css's theme blocks.
     theme: Literal["dark", "light", "midnight", "sunset"] | None = Field(default=None)
+    appear_offline: bool | None = Field(default=None)
 
 
 class UserDirectoryRead(BaseModel):

backend/app/ws/chat.py

@@ -9,6 +9,7 @@ from app.database import get_db
 from app.models import ApiToken, Message, MessageFile, MessageImage, RoomMembership, User
 from app.services.bot_service import resolve_token
 from app.services.message_events import (
+    broadcast_member_updated,
     broadcast_message_update,
     broadcast_new_message,
     broadcast_reaction_update,
@@ -76,9 +77,17 @@ async def chat_endpoint(websocket: WebSocket, db: AsyncSession = Depends(get_db)
     await websocket.accept()
     manager = websocket.app.state.connection_manager
     presence = websocket.app.state.presence
+    global_presence = websocket.app.state.global_presence
     broadcaster = websocket.app.state.broadcaster
     joined_rooms: set[uuid.UUID] = set()
     manager.register_user(user.id, websocket)
+    # Only broadcast on a genuine offline->online transition (this user's
+    # first open connection), not for every extra tab -- broadcast_member_
+    # updated tells every room this user's in to refresh, which would be
+    # wasted churn on a transition that didn't actually change anything
+    # visible.
+    if await global_presence.connect(user.id):
+        await broadcast_member_updated(db, broadcaster, user.id)
 
     try:
         while True:
@@ -229,3 +238,5 @@ async def chat_endpoint(websocket: WebSocket, db: AsyncSession = Depends(get_db)
         manager.unregister_user(user.id, websocket)
         for room_id in joined_rooms:
             await presence.leave(room_id, user.id)
+        if await global_presence.disconnect(user.id):
+            await broadcast_member_updated(db, broadcaster, user.id)

backend/app/ws/global_presence.py

@@ -0,0 +1,51 @@
+import uuid
+
+from redis.asyncio import Redis
+
+
+class GlobalPresence:
+    """Cross-instance "does this user have the app open at all right now,"
+    independent of which (if any) room they currently have open -- backing
+    the online/offline presence dot shown wherever a user's avatar renders.
+    A single Redis hash (field = user_id, value = connection refcount),
+    parallel to but separate from Presence's per-room hashes.
+
+    Refcounted for the same reason as Presence: multiple tabs/instances for
+    one user shouldn't flip them offline until the last connection closes.
+    """
+
+    def __init__(self, redis: Redis) -> None:
+        self._redis = redis
+
+    def _key(self) -> str:
+        return "presence:global"
+
+    async def connect(self, user_id: uuid.UUID) -> bool:
+        """Returns True iff this was the user's first open connection --
+        a genuine offline->online transition worth telling anyone about."""
+        count = await self._redis.hincrby(self._key(), str(user_id), 1)
+        return count == 1
+
+    async def disconnect(self, user_id: uuid.UUID) -> bool:
+        """Returns True iff this was the user's last open connection -- a
+        genuine online->offline transition."""
+        key = self._key()
+        field = str(user_id)
+        remaining = await self._redis.hincrby(key, field, -1)
+        if remaining <= 0:
+            await self._redis.hdel(key, field)
+            return True
+        return False
+
+    async def is_online(self, user_id: uuid.UUID) -> bool:
+        return await self._redis.hexists(self._key(), str(user_id))
+
+    async def online_user_ids(self, user_ids: list[uuid.UUID]) -> set[uuid.UUID]:
+        if not user_ids:
+            return set()
+        values = await self._redis.hmget(self._key(), [str(u) for u in user_ids])
+        return {uid for uid, v in zip(user_ids, values) if v is not None}
+
+    async def all_online_user_ids(self) -> set[uuid.UUID]:
+        fields = await self._redis.hkeys(self._key())
+        return {uuid.UUID(f) for f in fields}

backend/tests/test_broadcast.py

@@ -8,6 +8,16 @@ def _unique(prefix: str) -> str:
     return f"{prefix}-{uuid.uuid4().hex[:8]}"
 
 
+def _recv(ws) -> dict:
+    """Reads the next frame, transparently discarding member_updated
+    presence-change broadcasts -- another connection in the same room going
+    online/offline is real, expected noise these tests aren't about."""
+    while True:
+        msg = ws.receive_json()
+        if msg.get("type") != "member_updated":
+            return msg
+
+
 def _fake_send_email(monkeypatch):
     calls = []
 
@@ -61,7 +71,7 @@ def test_message_fans_out_across_instances(ws_client_factory):
             )
             assert alice_ws.receive_json()["type"] == "message"
 
-            received = bob_ws.receive_json()
+            received = _recv(bob_ws)
             assert received["type"] == "message"
             assert received["content"] == "hi from instance 1"
             assert received["username"] == alice["username"]
@@ -101,7 +111,7 @@ def test_presence_is_shared_across_instances(ws_client_factory, monkeypatch):
             # get the broadcast via Redis, not a push notification. If
             # presence were still process-local (pre-phase-5 behavior) he'd
             # look offline to instance1 and get a redundant push.
-            assert bob_ws.receive_json()["type"] == "message"
+            assert _recv(bob_ws)["type"] == "message"
 
             # Sync barrier: the handler processes frames strictly
             # sequentially, so a second (idempotent) join only acks once the

backend/tests/test_message_edit.py

@@ -8,6 +8,16 @@ def _unique(prefix: str) -> str:
     return f"{prefix}-{uuid.uuid4().hex[:8]}"
 
 
+def _recv(ws) -> dict:
+    """Reads the next frame, transparently discarding member_updated
+    presence-change broadcasts -- another connection in the same room going
+    online/offline is real, expected noise these tests aren't about."""
+    while True:
+        msg = ws.receive_json()
+        if msg.get("type") != "member_updated":
+            return msg
+
+
 def _register_ws(ws_client, username: str) -> dict:
     async def _seed():
         async with ws_client.session_factory() as session:
@@ -113,7 +123,7 @@ def test_edit_fans_out_across_instances(ws_client_factory):
             assert alice_ws.receive_json()["type"] == "joined"
             alice_ws.send_json({"type": "message", "room_id": room["id"], "content": "hi"})
             message = alice_ws.receive_json()
-            assert bob_ws.receive_json()["type"] == "message"
+            assert _recv(bob_ws)["type"] == "message"
 
             alice_ws.send_json(
                 {
@@ -125,6 +135,6 @@ def test_edit_fans_out_across_instances(ws_client_factory):
             )
             assert alice_ws.receive_json()["type"] == "message_update"
 
-            update = bob_ws.receive_json()
+            update = _recv(bob_ws)
             assert update["type"] == "message_update"
             assert update["content"] == "hi, edited"

backend/tests/test_presence.py

@@ -0,0 +1,132 @@
+import uuid
+
+from app.schemas.user import UserCreate
+from app.services.auth_service import register_user
+
+# Disconnect-side cleanup (GlobalPresence.disconnect, the offline broadcast)
+# is deliberately not exercised end-to-end here via a `with websocket_
+# connect(...)` block closing: Starlette's TestClient tears down a
+# websocket session by cancelling the server-side handler's task (confirmed
+# via asyncio.CancelledError while investigating a hang here), not by
+# delivering a real ASGI "websocket.disconnect" message the way an actual
+# client going away does -- so a `finally` block's own `await` calls can be
+# interrupted mid-cleanup in tests without that ever happening in
+# production. No existing test in this suite exercises presence.leave()
+# post-disconnect either, for the same reason. The connect-side behavior
+# below (the half that's actually reliably testable) is what matters most:
+# it proves the online transition and its broadcast work correctly.
+
+
+def _unique(prefix: str) -> str:
+    return f"{prefix}-{uuid.uuid4().hex[:8]}"
+
+
+def _register_ws(ws_client, username: str) -> dict:
+    async def _seed():
+        async with ws_client.session_factory() as session:
+            await register_user(
+                session,
+                UserCreate(username=username, email=f"{username}@example.com", password="password123"),
+            )
+
+    ws_client.portal.call(_seed)
+    resp = ws_client.post(
+        "/api/auth/login", json={"username_or_email": username, "password": "password123"}
+    )
+    assert resp.status_code == 200, resp.text
+    return resp.json()
+
+
+def test_member_status_reflects_connection(ws_client):
+    alice = _register_ws(ws_client, _unique("alice"))
+    room = ws_client.post("/api/rooms", json={"name": _unique("general")}).json()
+
+    members = ws_client.get(f"/api/rooms/{room['id']}/members").json()
+    assert members[0]["status"] == "offline"
+
+    with ws_client.websocket_connect("/ws/chat") as ws:
+        ws.send_json({"type": "join", "room_id": room["id"]})
+        assert ws.receive_json()["type"] == "joined"
+
+        members = ws_client.get(f"/api/rooms/{room['id']}/members").json()
+        assert members[0]["status"] == "online"
+
+
+def test_connect_broadcasts_presence_to_shared_room(ws_client):
+    alice = _register_ws(ws_client, _unique("alice"))
+    room = ws_client.post("/api/rooms", json={"name": _unique("general")}).json()
+
+    bob = _register_ws(ws_client, _unique("bob"))
+    ws_client.post(f"/api/rooms/{room['id']}/join")
+
+    ws_client.post(
+        "/api/auth/login", json={"username_or_email": alice["username"], "password": "password123"}
+    )
+    with ws_client.websocket_connect("/ws/chat") as alice_ws:
+        alice_ws.send_json({"type": "join", "room_id": room["id"]})
+        assert alice_ws.receive_json()["type"] == "joined"
+
+        ws_client.post(
+            "/api/auth/login", json={"username_or_email": bob["username"], "password": "password123"}
+        )
+        with ws_client.websocket_connect("/ws/chat"):
+            # bob connecting is a genuine offline->online transition for
+            # him -- alice, already joined, should hear about it even
+            # though she never sent anything and bob never joined a room.
+            assert alice_ws.receive_json() == {
+                "type": "member_updated",
+                "room_id": room["id"],
+                "user_id": bob["id"],
+            }
+
+
+def test_appear_offline_overrides_actual_connection(ws_client):
+    alice = _register_ws(ws_client, _unique("alice"))
+    room = ws_client.post("/api/rooms", json={"name": _unique("general")}).json()
+
+    with ws_client.websocket_connect("/ws/chat") as ws:
+        ws.send_json({"type": "join", "room_id": room["id"]})
+        assert ws.receive_json()["type"] == "joined"
+
+        members = ws_client.get(f"/api/rooms/{room['id']}/members").json()
+        assert members[0]["status"] == "online"
+
+        resp = ws_client.patch("/api/auth/me", json={"appear_offline": True})
+        assert resp.status_code == 200
+        assert resp.json()["appear_offline"] is True
+
+        # alice is joined to her own room, so the broadcast her own change
+        # triggers reaches her own socket.
+        assert ws.receive_json() == {"type": "member_updated", "room_id": room["id"], "user_id": alice["id"]}
+
+        members = ws_client.get(f"/api/rooms/{room['id']}/members").json()
+        assert members[0]["status"] == "offline"
+
+        resp = ws_client.patch("/api/auth/me", json={"appear_offline": False})
+        assert resp.status_code == 200
+        assert ws.receive_json()["type"] == "member_updated"
+
+        members = ws_client.get(f"/api/rooms/{room['id']}/members").json()
+        assert members[0]["status"] == "online"
+
+
+def test_online_users_endpoint_respects_appear_offline(ws_client):
+    alice = _register_ws(ws_client, _unique("alice"))
+    bob = _register_ws(ws_client, _unique("bob"))
+
+    ws_client.post(
+        "/api/auth/login", json={"username_or_email": alice["username"], "password": "password123"}
+    )
+    with ws_client.websocket_connect("/ws/chat"):
+        online = ws_client.get("/api/users/online").json()
+        assert alice["id"] in online
+        assert bob["id"] not in online
+
+        resp = ws_client.patch("/api/auth/me", json={"appear_offline": True})
+        assert resp.status_code == 200
+
+        online = ws_client.get("/api/users/online").json()
+        assert alice["id"] not in online
+
+    online = ws_client.get("/api/users/online").json()
+    assert alice["id"] not in online

backend/tests/test_push.py

@@ -97,6 +97,16 @@ def _unique(prefix: str) -> str:
     return f"{prefix}-{uuid.uuid4().hex[:8]}"
 
 
+def _recv(ws) -> dict:
+    """Reads the next frame, transparently discarding member_updated
+    presence-change broadcasts -- another connection in the same room going
+    online/offline is real, expected noise these tests aren't about."""
+    while True:
+        msg = ws.receive_json()
+        if msg.get("type") != "member_updated":
+            return msg
+
+
 def _fetch_subscriptions(ws_client, user_id: str) -> list[PushSubscription]:
     async def _query():
         async with ws_client.session_factory() as session:
@@ -172,7 +182,7 @@ def test_ws_message_no_push_when_member_connected(ws_client, monkeypatch):
             alice_ws.send_json({"type": "message", "room_id": room["id"], "content": "hi"})
             assert alice_ws.receive_json()["type"] == "message"
             # bob is connected too -- he should get the broadcast, not a push
-            assert bob_ws.receive_json()["type"] == "message"
+            assert _recv(bob_ws)["type"] == "message"
 
     assert calls == []
 

backend/tests/test_reactions.py

@@ -9,6 +9,16 @@ def _unique(prefix: str) -> str:
     return f"{prefix}-{uuid.uuid4().hex[:8]}"
 
 
+def _recv(ws) -> dict:
+    """Reads the next frame, transparently discarding member_updated
+    presence-change broadcasts -- another connection in the same room going
+    online/offline is real, expected noise these tests aren't about."""
+    while True:
+        msg = ws.receive_json()
+        if msg.get("type") != "member_updated":
+            return msg
+
+
 def _register_ws(ws_client, username: str) -> dict:
     async def _seed():
         async with ws_client.session_factory() as session:
@@ -121,8 +131,8 @@ def test_reaction_broadcasts_to_other_room_members(ws_client):
             alice_ws.send_json(
                 {"type": "reaction", "room_id": room["id"], "message_id": message["id"], "emoji": "🎉"}
             )
-            assert alice_ws.receive_json()["type"] == "reaction_update"
-            update = bob_ws.receive_json()
+            assert _recv(alice_ws)["type"] == "reaction_update"
+            update = _recv(bob_ws)
             assert update["type"] == "reaction_update"
             assert update["reactions"][0]["emoji"] == "🎉"
 

frontend/src/api/auth.ts

@@ -41,6 +41,16 @@ export function removeAvatar(): Promise<User> {
   return apiFetch<User>('/api/auth/me/avatar', { method: 'DELETE' })
 }
 
+// Deliberately its own call, same reasoning as updateTheme above -- a
+// manual override of the presence indicator, global (every room, not
+// per-room), independent of display_name/theme.
+export function updateAppearOffline(appearOffline: boolean): Promise<User> {
+  return apiFetch<User>('/api/auth/me', {
+    method: 'PATCH',
+    body: JSON.stringify({ appear_offline: appearOffline }),
+  })
+}
+
 export function changePassword(currentPassword: string, newPassword: string): Promise<void> {
   return apiFetch<void>('/api/auth/password', {
     method: 'PATCH',

frontend/src/api/users.ts

@@ -8,3 +8,11 @@ export function getUserAvatarUrl(userId: string, avatarFilename?: string | null)
 export function listUserDirectory(): Promise<UserDirectoryEntry[]> {
   return apiFetch<UserDirectoryEntry[]>('/api/users')
 }
+
+// A snapshot, not a live feed -- see backend/app/routers/users.py. Good
+// enough for surfaces that only need to be accurate as of page load (the
+// admin user list, the room-invite user search); chat surfaces get live
+// presence for free via the room member list instead.
+export function listOnlineUserIds(): Promise<string[]> {
+  return apiFetch<string[]>('/api/users/online')
+}

frontend/src/components/MessageList.tsx

@@ -1,7 +1,7 @@
 import { useEffect, useRef, useState } from 'react'
 import { getRoomFileUrl, getRoomImageUrl } from '../api/rooms'
 import { useAuth } from '../context/AuthContext'
-import { avatarUrlFor, displayNameFor, senderColorIndex } from '../lib/messageGrouping'
+import { avatarUrlFor, displayNameFor, senderColorIndex, statusFor } from '../lib/messageGrouping'
 import type { ChatMessageEnvelope, Message, MessageFileInfo, RoomMember } from '../types'
 import { EMOJI_PICKER_MAX_HEIGHT, EmojiPicker } from './EmojiPicker'
 import { FilePreviewModal, getPreviewKind } from './FilePreviewModal'
@@ -122,6 +122,7 @@ export function MessageList({ roomId, messages, members, onEdit, onReact }: Mess
                   username={msg.username}
                   colorIndex={senderColorIndex(msg.username, members)}
                   avatarUrl={avatarUrlFor(msg.username, members)}
+                  status={statusFor(msg.username, members)}
                 />
               )}
             </div>

frontend/src/components/ProfileModal.tsx

@@ -132,6 +132,7 @@ export function ProfileModal({ onClose }: ProfileModalProps) {
             colorIndex={hashIndex(user.username)}
             size={64}
             avatarUrl={avatarUrl}
+            status={user.appear_offline ? 'offline' : 'online'}
           />
           <div className="profile-modal-avatar-actions">
             <input

frontend/src/components/RoomInfoPanel.tsx

@@ -263,6 +263,7 @@ export function RoomInfoPanel({
                 colorIndex={i}
                 size={24}
                 avatarUrl={m.avatar_filename ? getUserAvatarUrl(m.user_id, m.avatar_filename) : null}
+                status={m.status}
               />
               <span className="room-info-member-name">{m.display_name || m.username}</span>
               {actions.length > 0 ? (

frontend/src/components/TopBar.tsx

@@ -1,6 +1,8 @@
 import { useEffect, useState } from 'react'
 import { useNavigate } from 'react-router-dom'
 import logo from '../assets/logo.png'
+import { updateAppearOffline } from '../api/auth'
+import { ApiError } from '../api/client'
 import { getUserAvatarUrl } from '../api/users'
 import { useAuth } from '../context/AuthContext'
 import { hashIndex } from '../lib/avatar'
@@ -10,13 +12,15 @@ import { UserAvatar } from './UserAvatar'
 import './TopBar.css'
 
 export function TopBar() {
-  const { user, logout } = useAuth()
+  const { user, updateUser, logout } = useAuth()
   const navigate = useNavigate()
   const [menuOpen, setMenuOpen] = useState(false)
   const [profileModalOpen, setProfileModalOpen] = useState(false)
   const [pushSubscribed, setPushSubscribed] = useState(false)
   const [pushBusy, setPushBusy] = useState(false)
   const [pushError, setPushError] = useState<string | null>(null)
+  const [presenceBusy, setPresenceBusy] = useState(false)
+  const [presenceError, setPresenceError] = useState<string | null>(null)
 
   useEffect(() => {
     getPushSubscriptionStatus().then(setPushSubscribed)
@@ -40,6 +44,20 @@ export function TopBar() {
     }
   }
 
+  async function handleTogglePresence() {
+    if (!user) return
+    setPresenceBusy(true)
+    setPresenceError(null)
+    try {
+      const updated = await updateAppearOffline(!user.appear_offline)
+      updateUser(updated)
+    } catch (err) {
+      setPresenceError(err instanceof ApiError ? err.message : String(err))
+    } finally {
+      setPresenceBusy(false)
+    }
+  }
+
   if (!user) return null
 
   return (
@@ -62,6 +80,7 @@ export function TopBar() {
             colorIndex={hashIndex(user.username)}
             size={30}
             avatarUrl={user.avatar_filename ? getUserAvatarUrl(user.id, user.avatar_filename) : null}
+            status={user.appear_offline ? 'offline' : 'online'}
           />
         </button>
         {menuOpen && (
@@ -79,6 +98,15 @@ export function TopBar() {
               >
                 Profile settings
               </button>
+              <button
+                type="button"
+                role="menuitem"
+                onClick={handleTogglePresence}
+                disabled={presenceBusy}
+              >
+                {user.appear_offline ? 'Show as online' : 'Appear offline'}
+              </button>
+              {presenceError && <div className="top-bar-menu-error">{presenceError}</div>}
               {user.is_site_admin && (
                 <button
                   type="button"

frontend/src/components/UserAvatar.css

@@ -1,3 +1,9 @@
+.user-avatar-wrap {
+  position: relative;
+  display: inline-flex;
+  flex: none;
+}
+
 .user-avatar {
   border-radius: var(--radius-pill);
   flex: none;
@@ -12,3 +18,19 @@
 .user-avatar-img {
   object-fit: cover;
 }
+
+.user-avatar-status-dot {
+  position: absolute;
+  right: -1px;
+  bottom: -1px;
+  border-radius: var(--radius-pill);
+  border: 2px solid var(--ds-surface);
+}
+
+.user-avatar-status-dot-online {
+  background: var(--ds-online);
+}
+
+.user-avatar-status-dot-offline {
+  background: var(--ds-danger);
+}

frontend/src/components/UserAvatar.tsx

@@ -6,26 +6,45 @@ interface UserAvatarProps {
   colorIndex: number
   size?: number
   avatarUrl?: string | null
+  // undefined -- no presence data for this context (e.g. a bot), don't
+  // render a dot at all, rather than guessing.
+  status?: 'online' | 'offline'
 }
 
-export function UserAvatar({ username, colorIndex, size = 28, avatarUrl }: UserAvatarProps) {
+export function UserAvatar({ username, colorIndex, size = 28, avatarUrl, status }: UserAvatarProps) {
+  const dotSize = Math.max(8, Math.round(size * 0.32))
+  const dot = status && (
+    <span
+      className={`user-avatar-status-dot user-avatar-status-dot-${status}`}
+      style={{ width: dotSize, height: dotSize }}
+      aria-label={status === 'online' ? 'Online' : 'Offline'}
+      title={status === 'online' ? 'Online' : 'Offline'}
+    />
+  )
+
   if (avatarUrl) {
     return (
+      <span className="user-avatar-wrap" style={{ width: size, height: size }}>
         <img
           src={avatarUrl}
           alt=""
           className="user-avatar user-avatar-img"
           style={{ width: size, height: size }}
         />
+        {dot}
+      </span>
     )
   }
 
   return (
+    <span className="user-avatar-wrap" style={{ width: size, height: size }}>
       <div
         className="user-avatar"
         style={{ width: size, height: size, background: accentForIndex(colorIndex) }}
       >
         {initials(username)}
       </div>
+      {dot}
+    </span>
   )
 }

frontend/src/components/UserPicker.tsx

@@ -1,5 +1,5 @@
 import { useEffect, useRef, useState } from 'react'
-import { getUserAvatarUrl } from '../api/users'
+import { getUserAvatarUrl, listOnlineUserIds } from '../api/users'
 import type { UserDirectoryEntry } from '../types'
 import { UserAvatar } from './UserAvatar'
 import './UserPicker.css'
@@ -16,6 +16,17 @@ export function UserPicker({ users, excludeUserIds, placeholder = 'Search users
   const [open, setOpen] = useState(false)
   const [highlighted, setHighlighted] = useState(0)
   const rootRef = useRef<HTMLDivElement>(null)
+  // A snapshot fetched once, not live -- see listOnlineUserIds's own
+  // comment. Fine for a search dropdown that's only open briefly.
+  const [onlineIds, setOnlineIds] = useState<Set<string>>(new Set())
+
+  useEffect(() => {
+    listOnlineUserIds()
+      .then((ids) => setOnlineIds(new Set(ids)))
+      .catch(() => {
+        // Non-critical -- the picker still works, just without dots.
+      })
+  }, [])
 
   const excluded = new Set(excludeUserIds ?? [])
   const q = query.trim().toLowerCase()
@@ -89,6 +100,7 @@ export function UserPicker({ users, excludeUserIds, placeholder = 'Search users
                 colorIndex={i}
                 size={22}
                 avatarUrl={u.avatar_filename ? getUserAvatarUrl(u.id, u.avatar_filename) : null}
+                status={onlineIds.has(u.id) ? 'online' : 'offline'}
               />
               <span className="user-picker-row-name">{u.display_name || u.username}</span>
               {u.display_name && <span className="user-picker-row-username">@{u.username}</span>}

frontend/src/lib/messageGrouping.ts

@@ -20,3 +20,7 @@ export function displayNameFor(username: string, members: RoomMember[]): string
   const member = members.find((m) => m.username === username)
   return member?.display_name || username
 }
+
+export function statusFor(username: string, members: RoomMember[]): 'online' | 'offline' | undefined {
+  return members.find((m) => m.username === username)?.status
+}

frontend/src/pages/AdminPage.tsx

@@ -25,7 +25,7 @@ import {
 } from '../api/admin'
 import { ApiError } from '../api/client'
 import { createApiToken, createBot, listApiTokens, listBots, revokeApiToken } from '../api/bots'
-import { getUserAvatarUrl } from '../api/users'
+import { getUserAvatarUrl, listOnlineUserIds } from '../api/users'
 import { UserPicker } from '../components/UserPicker'
 import { useAuth } from '../context/AuthContext'
 import { hashIndex } from '../lib/avatar'
@@ -55,6 +55,9 @@ export function AdminPage() {
   const { user: currentUser } = useAuth()
   const [tab, setTab] = useState<Tab>('users')
   const [users, setUsers] = useState<AdminUser[]>([])
+  // A snapshot, not live -- see listOnlineUserIds's own comment. Reloaded
+  // whenever the Users tab is opened, same cadence as the user list itself.
+  const [onlineIds, setOnlineIds] = useState<Set<string>>(new Set())
   const [rooms, setRooms] = useState<AdminRoom[]>([])
   const [transferringRoomId, setTransferringRoomId] = useState<string | null>(null)
   const [auditLog, setAuditLog] = useState<AuditLogEntry[]>([])
@@ -98,6 +101,11 @@ export function AdminPage() {
 
   function loadUsers() {
     listAdminUsers().then(setUsers).catch(reportError)
+    listOnlineUserIds()
+      .then((ids) => setOnlineIds(new Set(ids)))
+      .catch(() => {
+        // Non-critical -- the table still works, just without dots.
+      })
   }
 
   function loadRooms() {
@@ -449,6 +457,7 @@ export function AdminPage() {
                       colorIndex={hashIndex(u.username)}
                       size={28}
                       avatarUrl={u.avatar_filename ? getUserAvatarUrl(u.id, u.avatar_filename) : null}
+                      status={onlineIds.has(u.id) ? 'online' : 'offline'}
                     />
                   </td>
                   <td>{u.display_name || u.username}</td>

frontend/src/styles/tokens.css

@@ -21,6 +21,12 @@
      in the same neon-on-black family since the guide has no semantic red. */
   --ds-danger: #fc6060;
 
+  /* Presence dot -- offline reuses --ds-danger (already themed per-palette
+     below) rather than a second red token; online has no existing
+     equivalent so it gets one. Deliberately not overridden per-theme: a
+     universally recognizable green/red pair, not a brand color. */
+  --ds-online: #22c55e;
+
   --sans: Inter, ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
   --mono: "JetBrains Mono", "SFMono-Regular", Consolas, "Liberation Mono", monospace;
 

frontend/src/types.ts

@@ -9,6 +9,7 @@ export interface User {
   display_name: string | null
   theme: ThemeName | null
   avatar_filename: string | null
+  appear_offline: boolean
   created_at: string
 }
 
@@ -45,6 +46,7 @@ export interface RoomMember {
   avatar_filename: string | null
   role: RoomRole
   joined_at: string
+  status: 'online' | 'offline'
 }
 
 export type InviteStatus = 'pending' | 'accepted' | 'revoked'