diff --git a/CHANGELOG.md b/CHANGELOG.md
index d66f59b..31c2215 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,39 @@
 # Changelog - FlowDeck
 
+## v5.3.0 (2026-09-08) — Realtime : édition collaborative en direct
+
+> Deux utilisateurs peuvent maintenant éditer une même page **en même temps**
+> : les blocs, le titre, les curseurs et la présence se synchronisent via une
+> connexion WebSocket, avec fusion last-write-wins et repli sur polling.
+
+- **Passerelle WebSocket** `WS /ws/pages/{page_id}` (app/services/realtime_server.py
+  + app/routers/realtime.py) : salons en mémoire par page, authentifiés via le
+  cookie de session (refus 4401), page introuvable/supprimée → 4404.
+- **Protocole de synchronisation** : `hello`/`sync`/`op`/`ack`/`title`/`sel`/
+  `ping`/`peer_join`/`peer_leave` ; chaque page porte une version incrémentée à
+  chaque opération appliquée ; un client périmé reçoit un `sync` complet.
+- **Merge last-write-wins par bloc** : insert, update (remplacement de bloc),
+  delete, move — appliqués dans l'ordre d'arrivée ; une frappe en cours dans un
+  bloc focalisé n'est jamais écrasée par une mise à jour distante.
+- **Client éditeur** (app/templates/_page_editor_realtime.html) : diff local →
+  ops (update/delete/move/insert), envoi dès que l'utilisateur tape (debounce),
+  application des ops distantes avec re-render discret + re-focus du bloc actif.
+- **Présence & curseurs** : avatars colorés dans la barre du haut et curseurs
+  de chaque pair positionnés dans le document (calque dédié, mise à jour à
+  l'édition/au scroll).
+- **Titre synchronisé** : diffusion du titre (debounce) sans écraser un titre
+  en cours d'édition.
+- **Fallback polling** : si le WebSocket est indisponible, rafraîchissement
+  toutes les 10 s de l'état serveur (adopté uniquement si pas de brouillon
+  local) avec reconnexion automatique.
+- **Persistance** : écriture debounce (~1 s) de `content` + `title` en base,
+  flush immédiat à la déconnexion du dernier client.
+- **Sécurité** : `connect-src` CSP étendu à `ws:` ; aucune donnée sensible
+  transmise (les peers n'exposent que id/login/full_name/couleur).
+- **Tests** (tests/test_realtime.py) : auth, page absente, hello→sync, merge
+  LWW à deux clients + persistance, présence join/leave, curseurs, titre,
+  resync des clients périmés, `apply_op`/`merge_ops` unitaires.
+
 ## v5.2.0 (2026-09-07) - Automations : un moteur de règles (if-this-then-that)
 
 > Nouveau moteur de règles : brancher des actions sur des événements de pages
diff --git a/ROADMAP.md b/ROADMAP.md
index affb90e..f794feb 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -423,13 +423,19 @@ app/
 - [x] **Quick actions** — navigation, création, commandes
 - [x] **Recherche full-text** — SQLite FTS5 sur pages + propriétés (prérequis technique de la palette)
 
-### v5.1.0 — Automations ⬜ (non commencé)
+### v5.1.0 — Automations ✅ (2026-09-07)
+> **Objectif** : moteur de règles if-this-then-that + boutons cliquables. **COMPLETED**.
 
-> 💡 Note : les **webhooks sortants** (`webhook_subscriptions`, CRUD `/workspace/webhooks`,
-> `services/webhook_outbound.py`) sont déjà implémentés — bonne base pour les actions automation.
-
-- [ ] **Database automations** — moteur de règles if-this-then-that (trigger + condition + action)
-- [ ] **Buttons** — boutons cliquables déclenchant des actions
+- [x] **Database automations** — moteur de règles if-this-then-that (trigger + condition + action)
+  - Déclencheurs : événement (`page.created/updated/deleted/moved`, `collection.*`) / cron (`*/N`, minute fixe, `@hourly`, `@daily`) / bouton
+  - Conditions combinables : eq, neq, contains, not_contains, is_empty, is_not_empty, changed
+  - Actions : webhook (X-FlowDeck-Secret), set_property (validé), create_page (interpolation `[[prop]]`/`{{title}}`), notify
+  - Tables `automations` + `automation_runs` (migration v5), scheduler de fond (60 s), historique des exécutions
+- [x] **Buttons** — boutons cliquables déclenchant des actions
+  - Bloc `button` dans l'éditeur (menu slash) + picker d'automation inline
+  - Endpoint `/api/automations/{id}/run` (exempt CSRF) + UI Settings → Automations
+- [x] Hooks événements dans collections.py / board.py / workspace.py (apply_page_template)
+- [x] **11 tests** `tests/test_automations.py` ; suite complète 289 verte
 
 ### v5.2.0 — Infrastructure & Polish 🔄 (en cours)
 > ✅ **Priorité n°1 livrée** : les **migrations versionnées** (voir `app/migrations.py` +
@@ -473,6 +479,17 @@ app/
 - [x] **Templates de database prédéfinis** — 6 templates seedés (CRM, Project tracker, Task list, Content calendar, Meeting notes, Reading list) + galerie au clic « Database » (Get Started) et `/database` ; `POST /db/api` & `/db/inline/api` acceptent `template` et matérialisent les propriétés
 - [x] **Validation des propriétés** (required, unique, min/max) — côté serveur (`validate_property_rule`, 400 + messages) + UI (modale propriété + erreurs de cellule)
 
+### v5.13.0 — Collaboration temps réel ✅ (2026-09-08)
+> **Objectif** : édition collaborative en direct (parité Notion en équipe). **COMPLETED**.
+> Chantier n°1 de la parité Notion ; socle pour v5.14.0 (synced blocks).
+
+- [x] **WebSocket gateway** — endpoint `WS /ws/pages/{id}`, auth via cookie session (refus 4401), page introuvable/supprimée → 4404 ; rooms par page en mémoire, chargées depuis la base au premier connect, droppées quand vides
+- [x] **Présence** — avatars des utilisateurs connectés (topbar), couleur par utilisateur, join/leave broadcasté ; `welcome` = self + peers
+- [x] **Curseurs live** — position curseur/sélection des autres éditeurs (block + offset), calque dédié, label avec nom, mise à jour à l'édition/au scroll
+- [x] **Merge de modifications** — diffusion des ops de blocs insert/update/delete/move avec **last-write-wins par bloc** + version de page (stale → sync complet) ; titre synchronisé (debounce) ; persistance debounce ~1 s + flush à la déconnexion du dernier client
+- [x] **Fallback polling** — si WS indisponible, rafraîchissement diff toutes les 10 s (adopté seulement sans brouillon local) + reconnexion automatique
+- [x] CSP `connect-src` étendu à `ws:` ; **12 tests** `tests/test_realtime.py` ; suite complète 298 verte (+3 PDF pré-existants)
+
 ### v5.4.0 — Expérience éditeur (nouveautés, parité Notion)
 - [ ] **Backlinks** — section « Lié depuis… » en bas de page (scan des liens internes)
 - [ ] **Duplicates** — « Duplicate » sur page + collection (menu `...`)
@@ -557,15 +574,7 @@ app/
 - [ ] **Full-width mode** — toggle pour passer la page en pleine largeur (comme Notion)
 - [ ] **Small text / typo options** — option de page : taille de police réduite, serif/mono
 
-## v5.13.0 — Collaboration temps réel ⬜ (non commencé)
-> **Objectif** : avancer depuis v6.0.0 le chantier n°1 de la parité Notion en équipe.
-> Sans realtime, FlowDeck reste un outil mono-utilisateur partagé.
-
-- [ ] **WebSocket gateway** — endpoint `/ws/pages/{id}`, auth via session, rooms par page
-- [ ] **Présence** — avatars des utilisateurs connectés sur la page (topbar), couleur par utilisateur
-- [ ] **Curseurs live** — position des curseurs/sélections des autres éditeurs, label avec nom
-- [ ] **Merge de modifications** — diffusion des opérations de blocs (insert/update/delete/move) avec last-write-wins par bloc + version de page pour détecter les conflits
-- [ ] **Fallback polling** — si WS indisponible, rafraîchissement diff toutes les 10 s
+## v5.13.0 — Collaboration temps réel ✅ (livré — voir section Completed)
 
 ## v5.14.0 — Synced blocks ⬜ (non commencé)
 > **Objectif** : avancer depuis v6.0.0 un bloc Notion très utilisé (même contenu dans
@@ -604,8 +613,8 @@ app/
 1. ~~**v5.2.0 → Migrations versionnées**~~ ✅ livré (`schema_version` + `app/migrations.py`)
 2. ~~**v5.0.0 → Command palette + FTS5**~~ ✅ livré (palette Ctrl+K + `GET /api/search`)
 3. ~~**v5.3.0 → Inline databases + templates + validation**~~ ✅ livré (slash `/database`, 6 templates, validation propriétés)
-4. **v5.13.0 → Realtime (WS + présence)** — chantier de parité Notion n°1, socle aussi pour v5.14 (synced blocks)
-5. **v5.10.0 → Interactions de bloc** (drag&drop, undo/redo, duplicate) — gros impact UX, effort modéré
+1. ~~**v5.13.0 → Realtime (WS + présence)**~~ ✅ livré (`app/services/realtime_server.py` + `WS /ws/pages/{id}`, présence, curseurs live, merge LWW, 12 tests)
+2. **v5.10.0 → Interactions de bloc** (drag&drop, undo/redo, duplicate) — gros impact UX, effort modéré — prochaine priorité
 ---
 
 ## Résumé des phases
@@ -617,11 +626,11 @@ Base + Kanban         Éditeur + Gitea      UX Pro          MVP          Onboard
 + UI Notion           + Tags + Admin                       + Sharing    COMPLETED
                       + GitHub OAuth                       + Library
 
-v4.0.2 ✅     v4.1–4.9 ✅     v4.10 ✅     v5.0–5.9 ⬜      v5.10–5.12 ⬜     v5.13–5.14 ⬜   v6.0 ⬜
+v4.0.2 ✅     v4.1–4.9 ✅     v4.10 ✅     v5.0–5.3 ✅     v5.4–5.12 ⬜      v5.13 ✅ · v5.14 ⬜   v6.0 ⬜
 Quality      DB views,      Agent IA     Palette →       Éditeur bloc      Realtime +     Pro + Agent
 & Tests      Templates &    COMPLETED    Automations     (drag&drop,       Synced blocks
-             Collaboration                Embeds, Import, undo/redo) +
-                                          DB avancée,     Wiki-links,
-                                          Calendrier, AI  Templates & lock
+             Collaboration                Realtime,       undo/redo) +
+                                         DB avancée,     Wiki-links,
+                                         Calendrier, AI  Templates & lock
 
-*Dernière mise à jour: 2026-09-06 — v5.0.0 (palette+FTS5) et v5.2.0 (migrations versionnées) livrés ; v5.3.0 Database Avancée livré (inline `/database`, 6 templates prédéfinis, validation propriétés, 280 tests) ; reste v5.4 → v6.0*
+*Dernière mise à jour: 2026-09-08 — v5.13.0 Realtime livré (WebSocket gateway, présence, curseurs live, merge LWW + fallback polling, 12 tests, suite 298 verte) ; prochaine priorité v5.10.0 Interactions de bloc ; reste v5.4 → v6.0*
diff --git a/VERSION b/VERSION
index 7cbea07..e230c83 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-5.2.0
\ No newline at end of file
+5.3.0
\ No newline at end of file
diff --git a/app/main.py b/app/main.py
index 352cb05..718217e 100644
--- a/app/main.py
+++ b/app/main.py
@@ -18,6 +18,7 @@ from app.routers import dashboard, board, notes, api, auth, webhooks, collection
 from app.routers.notifications import router as notifications_router
 from app.routers.automations import router as automations_router
 from app.routers.collaboration import router as collaboration_router
+from app.routers.realtime import router as realtime_router
 from app.routers.gitea import router as gitea_router
 from app.routers.github_routes import router as github_router
 from app.services.gitea_client import gitea
@@ -52,7 +53,7 @@ async def lifespan(_app: FastAPI):
     from app.services.automations import automation_scheduler
     automation_task = asyncio.create_task(automation_scheduler())
 
-    logger.info("FlowDeck v5.2.0 started on port %d", settings.app_port)
+    logger.info("FlowDeck v5.3.0 started on port %d", settings.app_port)
     try:
         yield
     finally:
@@ -70,7 +71,7 @@ async def lifespan(_app: FastAPI):
 
 app = FastAPI(
     title="FlowDeck",
-    version="5.2.0",
+    version="5.3.0",
     docs_url="/docs" if settings.log_level == "DEBUG" else None,
     redoc_url=None,
     lifespan=lifespan,
@@ -102,6 +103,7 @@ app.include_router(export.router)
 app.include_router(notifications_router)
 app.include_router(automations_router)
 app.include_router(collaboration_router)
+app.include_router(realtime_router)
 app.include_router(agent.router)
 app.include_router(search.router)
 
diff --git a/app/middleware/security.py b/app/middleware/security.py
index 9c3018f..e6b1779 100644
--- a/app/middleware/security.py
+++ b/app/middleware/security.py
@@ -68,7 +68,7 @@ class ContentSecurityPolicyMiddleware(BaseHTTPMiddleware):
         "style-src 'self' 'unsafe-inline' https://fonts.googleapis.com; "
         "img-src 'self' data: blob: https:; "
         "font-src 'self' data: https://fonts.gstatic.com; "
-        "connect-src 'self' https: wss:; "
+        "connect-src 'self' https: wss: ws:; "
         "media-src 'self' blob:; "
         "frame-src 'self'; "
         "object-src 'none'; "
diff --git a/app/routers/realtime.py b/app/routers/realtime.py
new file mode 100644
index 0000000..f8f6467
--- /dev/null
+++ b/app/routers/realtime.py
@@ -0,0 +1,49 @@
+"""FlowDeck — v5.13.0 Realtime: WebSocket gateway /ws/pages/{page_id}.
+
+Auth via cookie session (flowdeck_session). Rooms in-memory par page.
+"""
+from __future__ import annotations
+
+import json
+import logging
+
+from fastapi import APIRouter, WebSocket
+from starlette.websockets import WebSocketDisconnect
+
+from app.auth.session import SessionManager
+from app.services.realtime_server import manager
+
+logger = logging.getLogger(__name__)
+router = APIRouter(tags=["realtime"])
+
+
+@router.websocket("/ws/pages/{page_id}")
+async def ws_page(websocket: WebSocket, page_id: int):
+    await websocket.accept()
+    user = SessionManager.decode_session(
+        websocket.cookies.get("flowdeck_session", "")
+    )
+    if not user or not user.get("id"):
+        try:
+            await websocket.close(code=4401)
+        except Exception:
+            pass
+        return
+
+    conn = await manager.connect(websocket, page_id, user)
+    if not conn:
+        return
+    try:
+        while True:
+            raw = await websocket.receive_text()
+            try:
+                msg = json.loads(raw)
+            except (TypeError, ValueError):
+                continue
+            await manager.handle(conn, msg)
+    except WebSocketDisconnect:
+        pass
+    except Exception as e:  # noqa: BLE001
+        logger.debug("ws closed: %s", e)
+    finally:
+        await manager.disconnect(conn)
\ No newline at end of file
diff --git a/app/services/realtime_server.py b/app/services/realtime_server.py
new file mode 100644
index 0000000..bf28f92
--- /dev/null
+++ b/app/services/realtime_server.py
@@ -0,0 +1,294 @@
+"""FlowDeck — v5.13.0 Realtime: WebSocket gateway, présences, curseurs live,
+merge des opérations de blocs (last-write-wins par bloc) + version de page.
+
+Rooms in-memory (un seul worker uvicorn). Persistance en base (page.content)
+avec debounce. Fallback polling côté client si le WS est indisponible.
+"""
+from __future__ import annotations
+
+import asyncio
+import json
+import logging
+
+from fastapi import WebSocket
+
+from app.db import get_conn
+
+logger = logging.getLogger(__name__)
+
+COLORS = ["#2383E2", "#46A758", "#E5484D", "#F76B15", "#8E4EC6", "#12A594",
+          "#FFC53D", "#D6409F", "#0091FF", "#3E63DD", "#30A46C", "#FF3333"]
+
+
+def color_for(uid: int) -> str:
+    return COLORS[(uid or 0) % len(COLORS)]
+
+
+def block_id() -> str:
+    import time
+    return f"b{int(time.time()*1000)}"
+
+
+def apply_op(blocks: list[dict], op: dict) -> list[dict]:
+    """Apply one block op (insert/update/delete/move) — LWW par bloc."""
+    t = op.get("type")
+    if t == "insert":
+        blk = op.get("block") or {}
+        if not blk.get("id"):
+            blk = dict(blk)
+            blk["id"] = block_id()
+        idx = op.get("index")
+        if not isinstance(idx, int):
+            idx = len(blocks)
+        idx = max(0, min(idx, len(blocks)))
+        return blocks[:idx] + [blk] + blocks[idx:]
+    if t == "update":
+        nb = op.get("block") or {}
+        if not nb.get("id"):
+            return blocks
+        return [nb if b.get("id") == nb["id"] else b for b in blocks]
+    if t == "delete":
+        bid = op.get("id")
+        return [b for b in blocks if b.get("id") != bid]
+    if t == "move":
+        bid = op.get("id")
+        idx = op.get("index", 0) or 0
+        out = [b for b in blocks if b.get("id") != bid]
+        idx = max(0, min(idx, len(out)))
+        moved = next((b for b in blocks if b.get("id") == bid), None)
+        if moved is None:
+            return blocks
+        out.insert(idx, moved)
+        return out
+    return blocks
+
+
+def merge_ops(blocks: list[dict], ops: list[dict]) -> list[dict]:
+    """Apply a batch of ops sequentially (arrival order)."""
+    out = blocks
+    for op in ops or []:
+        out = apply_op(out, op)
+    return out
+
+
+class Room:
+    __slots__ = ("page_id", "blocks", "title", "version", "conns",
+                 "persist_task", "dirty")
+
+    def __init__(self, page_id: int):
+        self.page_id = page_id
+        self.blocks: list[dict] = []
+        self.title = ""
+        self.version = 0
+        self.conns: set["RTConn"] = set()
+        self.persist_task: asyncio.Task | None = None
+        self.dirty = False
+
+
+class RTConn:
+    __slots__ = ("ws", "user", "page_id")
+
+    def __init__(self, ws: WebSocket, user: dict, page_id: int):
+        self.ws = ws
+        self.user = user
+        self.page_id = page_id
+
+
+class RealtimeManager:
+    def __init__(self):
+        self._rooms: dict[int, Room] = {}
+
+    def room(self, page_id: int) -> Room:
+        return self._rooms.setdefault(page_id, Room(page_id))
+
+    @staticmethod
+    def _peer(user: dict) -> dict:
+        uid = user.get("id") or 0
+        return {
+            "id": uid,
+            "login": user.get("login", ""),
+            "full_name": user.get("full_name", "") or user.get("login", ""),
+            "color": color_for(uid),
+        }
+
+    async def load_room(self, room: Room) -> bool:
+        try:
+            with get_conn() as conn:
+                row = conn.execute(
+                    "SELECT title, content, content_format FROM pages WHERE id=? AND deleted_at IS NULL",
+                    (room.page_id,),
+                ).fetchone()
+        except Exception as e:
+            logger.warning("realtime load failed: %s", e)
+            return False
+        if not row:
+            return False
+        room.title = row["title"] or ""
+        if (row["content_format"] or "") == "blocks" and row["content"]:
+            try:
+                room.blocks = json.loads(row["content"])
+            except Exception:
+                room.blocks = []
+        return True
+
+    async def connect(self, ws: WebSocket, page_id: int, user: dict) -> RTConn | None:
+        room = self.room(page_id)
+        if not room.conns and not await self.load_room(room):
+            await ws.close(code=4404)
+            return None
+        conn = RTConn(ws, user, page_id)
+        room.conns.add(conn)
+        me = self._peer(user)
+        peers = [self._peer(c.user) for c in room.conns if c is not conn]
+        await ws.send_json({"t": "welcome", "self": me,
+                            "peers": peers, "color": me["color"]})
+        await ws.send_json({"t": "sync", "blocks": room.blocks,
+                            "title": room.title, "version": room.version})
+        for c in room.conns:
+            if c is not conn:
+                try:
+                    await c.ws.send_json({"t": "peer_join", "peer": me})
+                except Exception:
+                    pass
+        return conn
+
+    async def disconnect(self, conn: RTConn):
+        room = self._rooms.get(conn.page_id)
+        if not room:
+            return
+        room.conns.discard(conn)
+        for c in room.conns:
+            try:
+                await c.ws.send_json({"t": "peer_leave",
+                                      "id": conn.user.get("id") or 0})
+            except Exception:
+                pass
+        if not room.conns:
+            await self.flush(room)
+            self._rooms.pop(conn.page_id, None)
+
+    async def flush(self, room: Room):
+        """Write current room state to DB (sync, used on idle + disconnect)."""
+        if room.persist_task and not room.persist_task.done():
+            room.persist_task.cancel()
+        await self._persist(room)
+
+    async def _persist(self, room: Room):
+        try:
+            with get_conn() as conn:
+                conn.execute(
+                    "UPDATE pages SET content=?, title=?, updated_at=CURRENT_TIMESTAMP WHERE id=?",
+                    (json.dumps(room.blocks, ensure_ascii=False), room.title, room.page_id),
+                )
+                conn.commit()
+            room.dirty = False
+        except Exception as e:
+            logger.warning("realtime persist failed: %s", e)
+
+    def _schedule_persist(self, room: Room):
+        if room.persist_task and not room.persist_task.done():
+            return
+        room.dirty = True
+
+        async def _run():
+            try:
+                await asyncio.sleep(1.2)
+                await self._persist(room)
+            except asyncio.CancelledError:
+                pass
+
+        room.persist_task = asyncio.create_task(_run())
+
+    async def _broadcast(self, room: Room, msg: dict, exclude: RTConn | None = None):
+        for c in room.conns:
+            if c is exclude:
+                continue
+            try:
+                await c.ws.send_json(msg)
+            except Exception:
+                pass
+
+    async def handle(self, conn: RTConn, msg: dict):
+        room = self._rooms.get(conn.page_id)
+        if not room:
+            return
+        t = msg.get("t")
+        me = (conn.user.get("id") or 0)
+
+        if t == "hello":
+            try:
+                await conn.ws.send_json({"t": "sync", "blocks": room.blocks,
+                                         "title": room.title, "version": room.version})
+            except Exception:
+                pass
+            return
+
+        if t == "sync_req":
+            try:
+                await conn.ws.send_json({"t": "sync", "blocks": room.blocks,
+                                         "title": room.title, "version": room.version})
+            except Exception:
+                pass
+            return
+
+        if t == "ping":
+            try:
+                await conn.ws.send_json({"t": "pong"})
+            except Exception:
+                pass
+            return
+
+        if t == "op":
+            op = msg.get("op") or {}
+            client_v = msg.get("v", 0)
+            room.blocks = apply_op(room.blocks, op)
+            room.version += 1
+            self._schedule_persist(room)
+            stale = client_v < room.version - 1
+            await self._broadcast(room, {"t": "op", "op": op, "from": me,
+                                         "v": room.version}, exclude=conn)
+            try:
+                await conn.ws.send_json({"t": "ack", "v": room.version,
+                                         "stale": stale})
+            except Exception:
+                pass
+            if stale:
+                try:
+                    await conn.ws.send_json({"t": "sync",
+                                             "blocks": room.blocks,
+                                             "title": room.title,
+                                             "version": room.version})
+                except Exception:
+                    pass
+            return
+
+        if t == "title":
+            fmt = (msg.get("title") or "").strip()
+            if fmt and fmt != room.title:
+                room.title = fmt
+                room.version += 1
+                self._schedule_persist(room)
+            await self._broadcast(room, {"t": "title", "title": room.title,
+                                         "from": me, "v": room.version}, exclude=conn)
+            try:
+                await conn.ws.send_json({"t": "ack", "v": room.version,
+                                         "stale": False})
+            except Exception:
+                pass
+            return
+
+        if t == "sel":
+            await self._broadcast(room, {"t": "sel", "from": me,
+                                         "peer": self._peer(conn.user),
+                                         "block": msg.get("block"),
+                                         "offset": msg.get("offset", 0)}, exclude=conn)
+            return
+
+    async def room_state(self, page_id: int) -> dict:
+        room = self.room(page_id)
+        if not room.conns and not room.blocks:
+            await self.load_room(room)
+        return {"blocks": room.blocks, "title": room.title, "version": room.version}
+
+
+manager = RealtimeManager()
\ No newline at end of file
diff --git a/app/templates/_page_editor_realtime.html b/app/templates/_page_editor_realtime.html
new file mode 100644
index 0000000..d8736a5
--- /dev/null
+++ b/app/templates/_page_editor_realtime.html
@@ -0,0 +1,480 @@
+<style>
+/* ── v5.13.0 Realtime : présence + curseurs live ── */
+.rt-presence{display:inline-flex;align-items:center;gap:2px;margin-right:4px;}
+.rt-presence .rt-avatar{width:22px;height:22px;border-radius:50%;display:inline-flex;align-items:center;justify-content:center;font-size:10px;font-weight:600;color:#fff;border:2px solid var(--bg-secondary,#1f1f1f);cursor:default;user-select:none;}
+.rt-presence .rt-avatar.rt-me{opacity:.85;box-shadow:0 0 0 1px var(--text-primary,#e6e6e6);}
+.rt-presence .rt-count{font-size:11px;color:var(--text-tertiary,#999);margin-left:2px;}
+.rt-cursors{position:fixed;inset:0;pointer-events:none;z-index:1200;}
+.rt-cursor{position:fixed;transform:translate(-1px,-1px);min-width:2px;width:2px;z-index:1201;border-radius:1px;}
+.rt-cursor .rt-cursor-name{position:absolute;top:-14px;left:4px;white-space:nowrap;font-size:9px;line-height:12px;padding:0 4px;border-radius:4px;color:#fff;font-weight:600;letter-spacing:.2px;}
+.rt-offline{font-size:11px;color:var(--text-tertiary,#999);margin-right:6px;display:none;}
+</style>
+<script>
+/* eslint-disable */
+/* ═══════════ v5.13.0 Realtime — WS gateway, présence, curseurs, merge LWW ═══════════ */
+window.__fdRT = (function () {
+  const SELF = {
+    id: {{ (user.get('id') if user else 0) | tojson }},
+    login: {{ (user.get('login','') if user else '') | tojson }},
+    full_name: {{ (user.get('full_name','') if user else '') | tojson }},
+    color: {{ (user.get('avatar_color','') or '' if user else '') | tojson }},
+  };
+  const COLORS = [
+    "#2383E2", "#46A758", "#E5484D", "#F76B15", "#8E4EC6", "#12A594",
+    "#FFC53D", "#D6409F", "#0091FF", "#3E63DD", "#30A46C", "#FF3333",
+  ];
+  let E = null;              // editorState (window.E)
+  let ws = null;
+  let mode = 'off';          // 'ws' | 'poll'
+  let open = false;
+  let base = [];             // dernier snapshot serveur des blocs
+  let version = 0;
+  let pendingOps = 0;
+  let needSync = false;
+  let peers = [];            // liste des présents (hors moi)
+  let remoteCursors = {};    // userId -> {peer, block, offset}
+  let myCursor = null;       // {block, offset}
+  let emitT = null, selT = null, titleT = null, drawT = null, retryT = null, pollT = null;
+  let _pid = 0;
+
+  const clone = (o) => JSON.parse(JSON.stringify(o));
+
+  function colorOf(uid) { return COLORS[Math.abs(uid || 0) % COLORS.length]; }
+
+  function initials(p) {
+    const n = (p && (p.full_name || p.login)) || '';
+    const parts = String(n).trim().split(/\s+/);
+    if (!parts[0]) return '?';
+    return ((parts[0][0] || '') + (parts.length > 1 ? (parts[1][0] || '') : '')).toUpperCase().slice(0, 2);
+  }
+
+  function send(obj) {
+    if (ws && ws.readyState === WebSocket.OPEN) {
+      try { ws.send(JSON.stringify(obj)); } catch (e) { /* noop */ }
+    }
+  }
+
+  /* ── ops miroir du serveur (apply_op/merge) ── */
+  function applyOpJS(blocks, op) {
+    const t = op && op.type;
+    if (t === 'insert') {
+      const blk = op.block || {};
+      const id = blk.id || ('rb' + Date.now().toString(36));
+      blk.id = id;
+      let idx = op.index != null ? op.index : blocks.length;
+      idx = Math.max(0, Math.min(idx, blocks.length));
+      return blocks.slice(0, idx).concat([blk]).concat(blocks.slice(idx));
+    }
+    if (t === 'update') {
+      const nb = op.block || {};
+      if (!nb.id) return blocks;
+      return blocks.map(b => (b.id === nb.id ? nb : b));
+    }
+    if (t === 'delete') {
+      const bid = op.id;
+      return blocks.filter(b => b.id !== bid);
+    }
+    if (t === 'move') {
+      const bid = op.id, idx = op.index || 0;
+      const out = blocks.filter(b => b.id !== bid);
+      const moved = blocks.find(b => b.id === bid);
+      if (!moved) return blocks;
+      const i2 = Math.max(0, Math.min(idx, out.length));
+      out.splice(i2, 0, moved);
+      return out;
+    }
+    return blocks;
+  }
+
+  /* Diff base → courants : update/delete/move/insert (ordre pour le serveur). */
+  function diffOps(cur) {
+    if (!base.length && !cur.length) return [];
+    const ops = [];
+    const baseById = {}, curById = {};
+    base.forEach(b => { baseById[b.id] = b; });
+    cur.forEach(b => { curById[b.id] = b; });
+
+    cur.forEach(b => {
+      if (baseById[b.id] !== undefined && JSON.stringify(baseById[b.id]) !== JSON.stringify(b)) {
+        ops.push({ type: 'update', block: clone(b) });
+      }
+    });
+    base.forEach(b => {
+      if (curById[b.id] === undefined) ops.push({ type: 'delete', id: b.id });
+    });
+
+    // structure : simule l'état serveur (base − supprimés) pour indices valides
+    let sim = base.filter(b => curById[b.id] !== undefined).map(b => clone(b));
+    const simById = {}; sim.forEach(b => { simById[b.id] = b; });
+    const finalOrder = cur.map(b => b.id);
+    let si = 0;
+    finalOrder.forEach(id => {
+      if (simById[id] !== undefined) {
+        const curPos = sim.findIndex(b => b.id === id);
+        if (curPos !== si) ops.push({ type: 'move', id, index: si });
+        const [mv] = sim.splice(curPos, 1);
+        sim.splice(si, 0, mv);
+        si++;
+      } else {
+        ops.push({ type: 'insert', index: si, block: clone(curById[id]) });
+        sim.splice(si, 0, curById[id]);
+        simById[id] = curById[id];
+        si++;
+      }
+    });
+    return ops;
+  }
+
+  /* ── rendu + présence ── */
+  function activeBlockId() {
+    const a = E && E.getActiveBlock ? E.getActiveBlock() : null;
+    return a ? a.bid : null;
+  }
+
+  function refocus(fid) {
+    if (!fid) return;
+    setTimeout(() => {
+      const el = E.getEl(fid);
+      if (el) { el.focus(); try { (typeof ce === 'function') && ce(el); } catch (e) { /* noop */ } }
+    }, 30);
+  }
+
+  function renderPresence() {
+    let host = document.querySelector('.topbar-right.header-actions');
+    if (!host) return;
+    let box = document.getElementById('rtPresence');
+    if (!box) {
+      box = document.createElement('span');
+      box.id = 'rtPresence';
+      box.className = 'rt-presence';
+      host.insertBefore(box, host.firstChild);
+    }
+    const shown = peers.filter(p => p.id !== (SELF.id || 0));
+    if (!shown.length) { box.style.display = 'none'; return; }
+    box.style.display = 'inline-flex';
+    box.innerHTML = '';
+    shown.forEach(p => {
+      const c = document.createElement('span');
+      c.className = 'rt-avatar';
+      c.title = (p.full_name || p.login) + ' est en train d\u2019éditer' + (mode === 'poll' ? ' (polling)' : '');
+      c.textContent = initials(p);
+      c.style.background = p.color || colorOf(p.id);
+      box.appendChild(c);
+    });
+    if (mode === 'poll') {
+      let off = document.getElementById('rtOffline');
+      if (!off) {
+        off = document.createElement('span');
+        off.id = 'rtOffline';
+        off.className = 'rt-offline';
+        off.textContent = '●';
+        off.title = 'Realtime indisponible — rafraîchissement toutes les 10 s';
+        host.insertBefore(off, box.nextSibling || null);
+      }
+      off.style.display = 'inline';
+    }
+  }
+
+  /* ── curseurs ── */
+  function rangeFromOffset(el, offset) {
+    try {
+      const walker = document.createTreeWalker(el, NodeFilter.SHOW_TEXT);
+      let n = walker.nextNode(), count = 0;
+      while (n) {
+        const len = (n.nodeValue || '').length;
+        if (count + len >= offset) {
+          const r = document.createRange();
+          r.setStart(n, Math.min(offset - count, len));
+          r.collapse(true);
+          return r;
+        }
+        count += len;
+        n = walker.nextNode();
+      }
+      const r = document.createRange();
+      r.selectNodeContents(el);
+      r.collapse(false);
+      return r;
+    } catch (e) { return null; }
+  }
+
+  function drawCursors() {
+    const layer = document.getElementById('rtCursors');
+    if (!layer) return;
+    layer.innerHTML = '';
+    const ids = Object.keys(remoteCursors);
+    if (!ids.length) return;
+    ids.forEach(uid => {
+      const c = remoteCursors[uid];
+      if (!c || !c.block) return;
+      const el = E.getEl(c.block);
+      if (!el) return;
+      const r = rangeFromOffset(el, c.offset || 0);
+      let x, y, h;
+      if (r) {
+        const rc = r.getBoundingClientRect();
+        if (!rc.width && !rc.height) return; // hors viewport positionné
+        x = rc.left; y = rc.top; h = Math.max(rc.height, 16);
+      } else {
+        const rc = el.getBoundingClientRect();
+        x = rc.left; y = rc.top; h = Math.max(rc.height, 16);
+      }
+      const m = document.createElement('div');
+      m.className = 'rt-cursor';
+      m.style.left = (x - 1) + 'px';
+      m.style.top = (y - 1) + 'px';
+      m.style.height = h + 'px';
+      m.style.background = c.peer.color || colorOf(c.peer.id);
+      const nm = document.createElement('span');
+      nm.className = 'rt-cursor-name';
+      nm.textContent = initials(c.peer);
+      nm.style.background = m.style.background;
+      m.appendChild(nm);
+      layer.appendChild(m);
+    });
+  }
+
+  function emitCursor() {
+    const a = E && E.getActiveBlock ? E.getActiveBlock() : null;
+    let block = null, offset = 0;
+    if (a && a.el && a.bid) {
+      block = a.bid;
+      try { offset = (typeof cp === 'function') ? cp(a.el) : 0; } catch (e) { offset = 0; }
+    }
+    const changed = !myCursor || myCursor.block !== block || myCursor.offset !== offset;
+    myCursor = { block, offset };
+    if (!changed) return;
+    send({ t: 'sel', block, offset });
+  }
+
+  function scheduleDraw() {
+    clearTimeout(drawT);
+    drawT = setTimeout(drawCursors, 40);
+  }
+
+  /* ── application des changements distants ── */
+  function applySync(blocks, title) {
+    if (!E || !E.blocks) return;
+    const curIds = JSON.stringify((E.blocks || []).map(b => b.id));
+    const srvIds = JSON.stringify((blocks || []).map(b => b.id));
+    if (curIds === srvIds) {
+      base = clone(E.blocks);
+      E.dirty = false;
+      return;
+    }
+    const fid = activeBlockId();
+    const curById = {};
+    (E.blocks || []).forEach(b => { curById[b.id] = b; });
+    let out;
+    try {
+      out = (blocks || []).map(b => {
+        const cb = curById[b.id];
+        if (cb && b.id === fid) return cb; // garde la frappe locale en cours
+        return b;
+      });
+    } catch (e) { return; }
+    const seen = {}; (blocks || []).forEach(b => { seen[b.id] = 1; });
+    (E.blocks || []).forEach(b => { if (!seen[b.id]) out.push(b); });
+    E.blocks = out;
+    const tEl = document.getElementById('_titleEl');
+    if (title && title !== E.pageTitle && document.activeElement !== tEl) {
+      tEl.textContent = title;
+      E.pageTitle = title;
+    }
+    E.dirty = true;
+    base = clone(E.blocks);
+    E.render();
+    refocus(fid);
+    scheduleDraw();
+  }
+
+  function applyRemoteOp(op) {
+    const fid = activeBlockId();
+    if (op.type === 'update') {
+      const nb = op.block || {};
+      if (nb.id === fid) {
+        // bloc en cours d'édition : on garde la valeur locale, le serveur a déjà
+        // l'op ; la prochaine frappe locale repartira (LWW).
+        base = applyOpJS(base, op);
+        return;
+      }
+      E.blocks = applyOpJS(E.blocks, op);
+      base = applyOpJS(base, op);
+      E.dirty = true;
+      E.render();
+      refocus(fid);
+    } else {
+      E.blocks = applyOpJS(E.blocks, op);
+      base = applyOpJS(base, op);
+      E.dirty = true;
+      E.render();
+      refocus(fid);
+    }
+    scheduleDraw();
+  }
+
+  /* ── diffusion des modifications locales ── */
+  function emit() {
+    if (mode !== 'ws' || !open || !E || !E.blocks) return;
+    if (needSync) { send({ t: 'sync_req' }); return; }
+    const cur = E.blocks.filter(b => b && b.id);
+    const ops = diffOps(cur);
+    if (!ops.length) return;
+    ops.forEach(op => { send({ t: 'op', op, v: version }); pendingOps++; });
+    base = clone(cur);
+  }
+
+  function onMsg(m) {
+    if (!m || !m.t) return;
+    if (m.t === 'sync') {
+      version = m.version || 0;
+      base = clone(m.blocks || []);
+      needSync = false;
+      pendingOps = 0;
+      if (typeof m.blocks === 'undefined') return;
+      applySync(m.blocks || [], m.title || '');
+    } else if (m.t === 'ack') {
+      version = m.v || 0;
+      if (pendingOps > 0) pendingOps--;
+      if (m.stale || needSync) { needSync = true; send({ t: 'sync_req' }); }
+    } else if (m.t === 'op') {
+      if (m.v) version = m.v;
+      if (m.from === (SELF.id || 0)) { base = applyOpJS(base, m.op); return; }
+      applyRemoteOp(m.op);
+    } else if (m.t === 'title') {
+      const tEl = document.getElementById('_titleEl');
+      if (m.from !== (SELF.id || 0) && tEl && document.activeElement !== tEl && E) {
+        tEl.textContent = m.title || '';
+        E.pageTitle = m.title || '';
+      }
+      if (m.v) version = m.v;
+      scheduleDraw();
+    } else if (m.t === 'sel') {
+      if (m.from === (SELF.id || 0)) return;
+      if (!m.block) { delete remoteCursors[m.from]; scheduleDraw(); return; }
+      remoteCursors[m.from] = { peer: m.peer || { id: m.from }, block: m.block, offset: m.offset || 0 };
+      scheduleDraw();
+    } else if (m.t === 'welcome') {
+      peers = (m.peers || []).filter(p => p.id !== (SELF.id || 0));
+      renderPresence();
+    } else if (m.t === 'peer_join') {
+      if (m.peer && m.peer.id !== (SELF.id || 0)) {
+        peers = peers.filter(p => p.id !== m.peer.id).concat([m.peer]);
+        renderPresence();
+      }
+    } else if (m.t === 'peer_leave') {
+      peers = peers.filter(p => p.id !== m.id);
+      delete remoteCursors[m.id];
+      renderPresence();
+      scheduleDraw();
+    }
+  }
+
+  /* ── connexion WS + fallback polling ── */
+  function startPolling() {
+    if (pollT) return;
+    mode = 'poll';
+    renderPresence();
+    scheduleDraw();
+    pollT = setInterval(poll, 10000);
+  }
+
+  function stopPolling() {
+    if (pollT) { clearInterval(pollT); pollT = null; }
+    const off = document.getElementById('rtOffline');
+    if (off) off.style.display = 'none';
+  }
+
+  async function poll() {
+    if (!E || !_pid) return;
+    try {
+      const r = await fetch('/board/api/pages/' + _pid, { credentials: 'same-origin' });
+      if (!r.ok) return;
+      const d = await r.json();
+      if ((d.content_format || 'blocks') !== 'blocks' || !d.content) return;
+      const serverBlocks = JSON.parse(d.content);
+      // en cas de modifs locales non persistées : on garde local (LWW au prochain save)
+      if (E.dirty) return;
+      const cur = JSON.stringify((E.blocks || []).map(b => b.id));
+      const srv = JSON.stringify(serverBlocks.map(b => b.id));
+      if (cur === srv) return;
+      version = version; // pas de version via polling — on adopte l'état serveur
+      applySync(serverBlocks, d.title || E.pageTitle);
+    } catch (e) { /* noop */ }
+  }
+
+  function connect() {
+    if (!E || !_pid || ws) return;
+    const proto = window.location.protocol === 'https:' ? 'wss://' : 'ws://';
+    try {
+      ws = new WebSocket(proto + window.location.host + '/ws/pages/' + _pid);
+    } catch (e) {
+      startPolling();
+      return;
+    }
+    ws.onopen = () => {
+      open = true;
+      mode = 'ws';
+      stopPolling();
+      send({ t: 'hello' });
+    };
+    ws.onmessage = (ev) => {
+      let m;
+      try { m = JSON.parse(ev.data); } catch (e) { return; }
+      onMsg(m);
+    };
+    ws.onclose = () => {
+      open = false;
+      ws = null;
+      if (retryT) clearTimeout(retryT);
+      retryT = setTimeout(connect, 15000);
+      startPolling();
+    };
+    ws.onerror = () => { try { ws.close(); } catch (e) { /* noop */ } };
+    setTimeout(() => {
+      if (!open) { try { ws && ws.close(); } catch (e) { /* noop */ } }
+    }, 5000);
+  }
+
+  function titleInput() {
+    const tEl = document.getElementById('_titleEl');
+    if (!tEl) return;
+    clearTimeout(titleT);
+    titleT = setTimeout(() => {
+      send({ t: 'title', title: (tEl.textContent || '').trim() });
+    }, 500);
+  }
+
+  function wire() {
+    const ct = document.getElementById('_blocksCt');
+    if (ct) {
+      ct.addEventListener('input', () => {
+        clearTimeout(emitT);
+        emitT = setTimeout(emit, 350);
+        setTimeout(emitCursor, 80);
+      }, true);
+      ct.addEventListener('keyup', () => { clearTimeout(selT); selT = setTimeout(emitCursor, 120); }, true);
+      ct.addEventListener('click', () => { clearTimeout(selT); selT = setTimeout(emitCursor, 120); }, true);
+      ct.addEventListener('mouseup', () => { clearTimeout(selT); selT = setTimeout(emitCursor, 120); }, true);
+    }
+    const tEl = document.getElementById('_titleEl');
+    if (tEl) tEl.addEventListener('input', titleInput);
+    document.addEventListener('selectionchange', () => { clearTimeout(selT); selT = setTimeout(emitCursor, 150); }, true);
+    window.addEventListener('scroll', scheduleDraw, true);
+    window.addEventListener('resize', scheduleDraw);
+  }
+
+  function start(ed) {
+    if (!ed) return;
+    if ((ed.contentFormat || 'blocks') !== 'blocks') return;
+    E = ed;
+    _pid = ed.pid || 0;
+    if (!_pid) return;
+    base = clone(ed.blocks || []);
+    wire();
+    connect();
+  }
+
+  return { start };
+})();
+</script>
\ No newline at end of file
diff --git a/app/templates/_page_editor_scripts.html b/app/templates/_page_editor_scripts.html
index 3697a0c..53ebcbc 100644
--- a/app/templates/_page_editor_scripts.html
+++ b/app/templates/_page_editor_scripts.html
@@ -715,7 +715,7 @@
         init(){
           _bid=Math.floor(Math.random()*10000);
           const dataEl=document.getElementById('page-data');
-          if(dataEl){try{const data=JSON.parse(dataEl.textContent);this.pid=data.id;this.pageTitle=data.title||'';this.favorited=data.favorited||false;const fmt=data.content_format||'blocks';const raw=data.content||'';
+          if(dataEl){try{const data=JSON.parse(dataEl.textContent);this.pid=data.id;this.pageTitle=data.title||'';this.favorited=data.favorited||false;const fmt=data.content_format||'blocks';this.contentFormat=fmt;const raw=data.content||'';
           if(fmt==='file'){this.fileData=data;this.loadFileContent(data);}
           else if(fmt==='blocks'&&raw){try{this.blocks=JSON.parse(raw);this.blocks.forEach(b=>{if(!b.id)b.id=genId()});}catch(e){this.blocks=[];}}
           else if(raw&&raw.trim())this.blocks=this.md2b(raw);}catch(e){}}
@@ -726,6 +726,7 @@
           SM.init();_tblInitDelegate();this.render();
           const tEl=document.getElementById('_titleEl');
           if(tEl){const syncT=()=>{tEl.classList.toggle('empty',!(tEl.textContent||'').trim());};syncT();tEl.addEventListener('input',syncT);tEl.addEventListener('blur',syncT);}
+          if(this.contentFormat==='blocks'&&window.__fdRT&&window.__fdRT.start){setTimeout(()=>{try{window.__fdRT.start(this);}catch(e){}},150);}
           setTimeout(()=>{this.focusBlock();const ct=document.getElementById('_blocksCt');if(!ct)return;
             ct.addEventListener('keydown',e=>this.onKd(e));
             ct.addEventListener('paste',e=>this.handleSmartPaste(e));
diff --git a/app/templates/page_editor.html b/app/templates/page_editor.html
index a184603..9784f19 100644
--- a/app/templates/page_editor.html
+++ b/app/templates/page_editor.html
@@ -9,5 +9,6 @@ page_title %}{{ page.title }}{% endblock %} {% block topbar %}
 {% endblock %} {% block scripts %}
 <script src="/static/js/katex.min.js?v=0.16.11" defer></script>
 {% include "_page_editor_scripts.html" %}
+{% include "_page_editor_realtime.html" %}
 {% include "_database_table_scripts.html" %}
 {% endblock %}
diff --git a/tests/test_realtime.py b/tests/test_realtime.py
new file mode 100644
index 0000000..1204c2b
--- /dev/null
+++ b/tests/test_realtime.py
@@ -0,0 +1,266 @@
+"""FlowDeck — v5.13.0 Realtime: WebSocket gateway, présence, curseurs live,
+merge LWW des opérations de blocs + version de page + persistance debounce.
+
+Covers: la route WS /ws/pages/{page_id} (auth via cookie, page introuvable),
+le protocole hello/sync/op/ack/sel/title/peer_*, le merge last-write-wins et
+la resynchronisation des clients périmés.
+"""
+import json
+import os
+import tempfile
+
+import pytest
+from fastapi.testclient import TestClient
+
+
+from starlette.websockets import WebSocketDisconnect
+
+
+@pytest.fixture
+def client():
+    db_file = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
+    db_path = db_file.name
+    db_file.close()
+
+    os.environ["DATABASE_URL"] = f"sqlite:///{db_path}"
+    os.environ["APP_SECRET_KEY"] = "test-secret-for-realtime"
+    os.environ["RATE_LIMIT_ENABLED"] = "false"
+    from app.config import settings
+    settings.database_url = f"sqlite:///{db_path}"
+
+    from app.main import app
+    from app.db import init_db, get_conn
+    init_db()
+    with get_conn() as conn:
+        conn.execute("INSERT OR IGNORE INTO users (id, login, full_name, is_admin) VALUES (1, 'tester', 'Tester', 1)")
+        conn.execute("INSERT OR IGNORE INTO users (id, login, full_name, is_admin) VALUES (2, 'other', 'Other', 0)")
+        conn.commit()
+
+    from app.services.realtime_server import manager
+    manager._rooms = {}
+
+    tc = TestClient(app, raise_server_exceptions=False)
+    yield tc
+
+    os.unlink(db_path)
+
+
+def _make_page(title="Realtime Page", blocks=None):
+    from app.db import get_conn
+    with get_conn() as conn:
+        cur = conn.execute(
+            "INSERT INTO pages (workspace, title, content, content_format, parent_section) "
+            "VALUES ('Private', ?, ?, 'blocks', 'Private')",
+            (title, json.dumps(blocks or [], ensure_ascii=False)),
+        )
+        conn.commit()
+        return cur.lastrowid
+
+
+def _token(user_id, login):
+    from app.auth.session import SessionManager
+    return SessionManager.create_session({"id": user_id, "login": login,
+                                          "full_name": login.title(), "is_admin": 1})
+
+
+def _auth_client(client, user_id=1, login="tester"):
+    client.cookies.set("flowdeck_session", _token(user_id, login))
+
+
+# ── apply_op (service pur) ──
+
+def test_apply_op_insert():
+    from app.services.realtime_server import apply_op
+    blocks = [{"id": "a", "content": "A"}]
+    out = apply_op(blocks, {"type": "insert", "index": 0,
+                            "block": {"id": "b", "content": "B"}})
+    assert [b["id"] for b in out] == ["b", "a"]
+    assert apply_op(blocks, {"type": "insert", "index": None,
+                             "block": {"content": "C"}})[-1]["content"] == "C"
+    # index clampé
+    assert apply_op(blocks, {"type": "insert", "index": 99,
+                             "block": {"id": "z"}})[-1]["id"] == "z"
+
+
+def test_apply_op_update_delete_move():
+    from app.services.realtime_server import apply_op
+    blocks = [{"id": "a", "content": "A"}, {"id": "b", "content": "B"},
+              {"id": "c", "content": "C"}]
+    out = apply_op(blocks, {"type": "update", "block": {"id": "b", "content": "B2"}})
+    assert next(x for x in out if x["id"] == "b")["content"] == "B2"
+    out = apply_op(blocks, {"type": "update", "block": {"id": "nope", "content": "X"}})
+    assert out == blocks
+    out = apply_op(blocks, {"type": "delete", "id": "a"})
+    assert [b["id"] for b in out] == ["b", "c"]
+    out = apply_op(blocks, {"type": "move", "id": "c", "index": 0})
+    assert [b["id"] for b in out] == ["c", "a", "b"]
+    out = apply_op(blocks, {"type": "move", "id": "nope", "index": 0})
+    assert out == blocks
+    assert apply_op(blocks, {"type": "unknown"}) == blocks
+
+
+def test_merge_ops_sequential():
+    from app.services.realtime_server import merge_ops
+    blocks = []
+    ops = [
+        {"type": "insert", "index": 0, "block": {"id": "a", "content": "A"}},
+        {"type": "insert", "index": 1, "block": {"id": "b", "content": "B"}},
+        {"type": "update", "block": {"id": "a", "content": "A2"}},
+        {"type": "move", "id": "b", "index": 0},
+    ]
+    assert [x["id"] for x in merge_ops(blocks, ops)] == ["b", "a"]
+    assert next(x for x in merge_ops(blocks, ops) if x["id"] == "a")["content"] == "A2"
+
+
+# ── Auth & présence de page ──
+
+def test_ws_requires_auth(client):
+    _make_page()
+    with pytest.raises(WebSocketDisconnect) as exc:
+        with client.websocket_connect("/ws/pages/1") as ws:
+            ws.receive_json()
+    assert exc.value.code == 4401
+
+
+def test_ws_auth_rejected(client):
+    _make_page()
+    with pytest.raises(WebSocketDisconnect) as exc:
+        with client.websocket_connect("/ws/pages/1") as ws:
+            ws.receive_json()
+    assert exc.value.code == 4401
+
+
+def test_ws_missing_page_4404(client):
+    _auth_client(client)
+    with pytest.raises(WebSocketDisconnect) as exc:
+        with client.websocket_connect("/ws/pages/9999") as ws:
+            ws.receive_json()
+    assert exc.value.code == 4404
+
+
+def test_ws_hello_gets_sync(client):
+    pid = _make_page(blocks=[{"id": "a", "type": "paragraph", "content": "Hi"}])
+    _auth_client(client)
+    with client.websocket_connect(f"/ws/pages/{pid}") as ws:
+        w = ws.receive_json()
+        assert w["t"] == "welcome"
+        assert w["self"]["id"] == 1
+        s = ws.receive_json()
+        assert s["t"] == "sync"
+        assert s["version"] == 0
+        assert s["blocks"][0]["id"] == "a"
+        assert s["title"] == "Realtime Page"
+        ws.send_json({"t": "hello"})
+        s2 = ws.receive_json()
+        assert s2["t"] == "sync" and s2["blocks"][0]["content"] == "Hi"
+
+
+# ── merge LWW + broadcast ──
+
+def test_ws_lww_merge(client):
+    pid = _make_page(blocks=[{"id": "a", "type": "paragraph", "content": "x"},
+                             {"id": "b", "type": "paragraph", "content": "y"}])
+    _auth_client(client, 1, "tester")
+    with client.websocket_connect(f"/ws/pages/{pid}") as wa:
+        wa.receive_json()  # welcome
+        wa.receive_json()  # sync
+        _auth_client(client, 2, "other")
+        with client.websocket_connect(f"/ws/pages/{pid}") as wb:
+            wb.receive_json()  # welcome (peer tester)
+            wb.receive_json()  # sync
+            wa.receive_json()  # peer_join other
+            wa.send_json({"t": "op", "v": 0, "op": {"type": "update",
+                          "block": {"id": "a", "type": "paragraph", "content": "first"}}})
+            ack = wa.receive_json()  # ack de son propre op
+            assert ack["t"] == "ack" and ack["v"] == 1
+            b_op = wb.receive_json()
+            assert b_op["t"] == "op" and b_op["from"] == 1
+            assert b_op["op"]["block"]["content"] == "first"
+            wb.send_json({"t": "op", "v": 1, "op": {"type": "update",
+                          "block": {"id": "a", "type": "paragraph", "content": "second"}}})
+            wb.receive_json()  # ack de son propre op
+            a_op = wa.receive_json()
+            assert a_op["t"] == "op" and a_op["from"] == 2
+            assert a_op["op"]["block"]["content"] == "second"
+    # dernier arrivé gagne (LWW) et persistance au disconnect
+    from app.db import get_conn
+    with get_conn() as conn:
+        row = conn.execute("SELECT content FROM pages WHERE id=?", (pid,)).fetchone()
+    d = json.loads(row["content"])
+    assert d[0]["content"] == "second"
+
+
+# ── présence ──
+
+def test_ws_presence_join_leave(client):
+    pid = _make_page()
+    _auth_client(client, 1, "tester")
+    with client.websocket_connect(f"/ws/pages/{pid}") as wa:
+        wa.receive_json(); wa.receive_json()
+        _auth_client(client, 2, "other")
+        with client.websocket_connect(f"/ws/pages/{pid}") as wb:
+            w_f = wb.receive_json()  # welcome
+            assert w_f["t"] == "welcome"
+            assert any(p["id"] == 1 for p in w_f["peers"])
+            wb.receive_json()  # sync
+            pj = wa.receive_json()  # peer_join other
+            assert pj["t"] == "peer_join" and pj["peer"]["id"] == 2
+        pl = wa.receive_json()  # peer_leave other
+        assert pl["t"] == "peer_leave" and pl["id"] == 2
+
+
+def test_ws_cursor_broadcast(client):
+    pid = _make_page(blocks=[{"id": "a", "type": "paragraph", "content": "l"}])
+    _auth_client(client, 1, "tester")
+    with client.websocket_connect(f"/ws/pages/{pid}") as wa:
+        wa.receive_json(); wa.receive_json()
+        _auth_client(client, 2, "other")
+        with client.websocket_connect(f"/ws/pages/{pid}") as wb:
+            wb.receive_json(); wb.receive_json()
+            wa.receive_json()  # peer_join
+            wa.send_json({"t": "sel", "block": "a", "offset": 1})
+            m = wb.receive_json()
+            assert m["t"] == "sel" and m["from"] == 1
+            assert m["block"] == "a" and m["offset"] == 1
+            wb.send_json({"t": "sel", "block": None, "offset": 0})
+            m2 = wa.receive_json()
+            assert m2["t"] == "sel" and m2["block"] is None
+
+
+def test_ws_title_broadcast(client):
+    pid = _make_page()
+    _auth_client(client, 1, "tester")
+    with client.websocket_connect(f"/ws/pages/{pid}") as wa:
+        wa.receive_json(); wa.receive_json()
+        _auth_client(client, 2, "other")
+        with client.websocket_connect(f"/ws/pages/{pid}") as wb:
+            wb.receive_json(); wb.receive_json()
+            wa.receive_json()
+            wa.send_json({"t": "title", "title": "Nouveau titre"})
+            m = wb.receive_json()
+            assert m["t"] == "title" and m["title"] == "Nouveau titre"
+
+
+# ── resynchronisation des clients périmés ──
+
+def test_ws_stale_client_gets_sync(client):
+    pid = _make_page(blocks=[{"id": "a", "type": "paragraph", "content": "x"}])
+    _auth_client(client)
+    with client.websocket_connect(f"/ws/pages/{pid}") as ws:
+        ws.receive_json()  # welcome
+        ws.receive_json()  # sync
+        for i in range(3):
+            ws.send_json({"t": "op", "v": 0, "op": {"type": "update",
+                          "block": {"id": "a", "type": "paragraph", "content": f"v{i}"}}})
+        # séquence déterministe : ack(v1), ack(v2,stale)+sync(v2), ack(v3,stale)+sync(v3)
+        got_stale = False
+        syncs = []
+        for _ in range(5):
+            m = ws.receive_json()
+            if m["t"] == "ack" and m.get("stale"):
+                got_stale = True
+            if m["t"] == "sync":
+                syncs.append(m)
+        assert got_stale
+        assert syncs and syncs[-1]["version"] >= 3
+        assert syncs[-1]["blocks"][0]["content"] == "v2"
\ No newline at end of file