feat: add live refresh via Server-Sent Events (SSE) with visual indicator (#5638)

Co-authored-by: Cursor Agent <cursoragent@cursor.com>
Co-authored-by: milvasic <milvasic@users.noreply.github.com>

server/router/api/v1/memo_service.go

@@ -141,6 +141,12 @@ func (s *APIV1Service) CreateMemo(ctx context.Context, request *v1pb.CreateMemoR
 		slog.Warn("Failed to dispatch memo created webhook", slog.Any("err", err))
 	}
 
+	// Broadcast live refresh event.
+	s.SSEHub.Broadcast(&SSEEvent{
+		Type: SSEEventMemoCreated,
+		Name: memoMessage.Name,
+	})
+
 	return memoMessage, nil
 }
 
@@ -471,6 +477,12 @@ func (s *APIV1Service) UpdateMemo(ctx context.Context, request *v1pb.UpdateMemoR
 		slog.Warn("Failed to dispatch memo updated webhook", slog.Any("err", err))
 	}
 
+	// Broadcast live refresh event.
+	s.SSEHub.Broadcast(&SSEEvent{
+		Type: SSEEventMemoUpdated,
+		Name: memoMessage.Name,
+	})
+
 	return memoMessage, nil
 }
 
@@ -539,6 +551,12 @@ func (s *APIV1Service) DeleteMemo(ctx context.Context, request *v1pb.DeleteMemoR
 		return nil, status.Errorf(codes.Internal, "failed to delete memo")
 	}
 
+	// Broadcast live refresh event.
+	s.SSEHub.Broadcast(&SSEEvent{
+		Type: SSEEventMemoDeleted,
+		Name: request.Name,
+	})
+
 	return &emptypb.Empty{}, nil
 }
 

server/router/api/v1/reaction_service.go

@@ -97,6 +97,12 @@ func (s *APIV1Service) UpsertMemoReaction(ctx context.Context, request *v1pb.Ups
 
 	reactionMessage := convertReactionFromStore(reaction)
 
+	// Broadcast live refresh event (reaction belongs to a memo).
+	s.SSEHub.Broadcast(&SSEEvent{
+		Type: SSEEventReactionUpserted,
+		Name: request.Reaction.ContentId,
+	})
+
 	return reactionMessage, nil
 }
 
@@ -136,6 +142,12 @@ func (s *APIV1Service) DeleteMemoReaction(ctx context.Context, request *v1pb.Del
 		return nil, status.Errorf(codes.Internal, "failed to delete reaction")
 	}
 
+	// Broadcast live refresh event (reaction belongs to a memo).
+	s.SSEHub.Broadcast(&SSEEvent{
+		Type: SSEEventReactionDeleted,
+		Name: reaction.ContentID,
+	})
+
 	return &emptypb.Empty{}, nil
 }
 

server/router/api/v1/sse_handler.go

@@ -0,0 +1,101 @@
+package v1
+
+import (
+	"fmt"
+	"log/slog"
+	"net/http"
+	"time"
+
+	"github.com/labstack/echo/v5"
+
+	"github.com/usememos/memos/server/auth"
+	"github.com/usememos/memos/store"
+)
+
+const (
+	// sseHeartbeatInterval is the interval between heartbeat pings to keep the connection alive.
+	sseHeartbeatInterval = 30 * time.Second
+)
+
+// RegisterSSERoutes registers the SSE endpoint on the given Echo instance.
+func RegisterSSERoutes(echoServer *echo.Echo, hub *SSEHub, storeInstance *store.Store, secret string) {
+	authenticator := auth.NewAuthenticator(storeInstance, secret)
+	echoServer.GET("/api/v1/sse", func(c *echo.Context) error {
+		return handleSSE(c, hub, authenticator)
+	})
+}
+
+// handleSSE handles the SSE connection for live memo refresh.
+// Authentication is done via Bearer token in the Authorization header,
+// or via the "token" query parameter (for EventSource which cannot set headers).
+func handleSSE(c *echo.Context, hub *SSEHub, authenticator *auth.Authenticator) error {
+	// Authenticate the request.
+	authHeader := c.Request().Header.Get("Authorization")
+	if authHeader == "" {
+		// Fall back to query parameter for native EventSource support.
+		if token := c.QueryParam("token"); token != "" {
+			authHeader = "Bearer " + token
+		}
+	}
+
+	result := authenticator.Authenticate(c.Request().Context(), authHeader)
+	if result == nil {
+		return c.JSON(http.StatusUnauthorized, map[string]string{"error": "authentication required"})
+	}
+
+	// Set SSE headers.
+	w := c.Response()
+	w.Header().Set("Content-Type", "text/event-stream")
+	w.Header().Set("Cache-Control", "no-cache")
+	w.Header().Set("Connection", "keep-alive")
+	w.Header().Set("X-Accel-Buffering", "no") // Disable nginx buffering
+	w.WriteHeader(http.StatusOK)
+
+	// Flush headers immediately.
+	if f, ok := w.(http.Flusher); ok {
+		f.Flush()
+	}
+
+	// Subscribe to the hub.
+	client := hub.Subscribe()
+	defer hub.Unsubscribe(client)
+
+	// Create a ticker for heartbeat pings.
+	heartbeat := time.NewTicker(sseHeartbeatInterval)
+	defer heartbeat.Stop()
+
+	ctx := c.Request().Context()
+
+	slog.Debug("SSE client connected")
+
+	for {
+		select {
+		case <-ctx.Done():
+			// Client disconnected.
+			slog.Debug("SSE client disconnected")
+			return nil
+
+		case data, ok := <-client.events:
+			if !ok {
+				// Channel closed, client was unsubscribed.
+				return nil
+			}
+			// Write SSE event.
+			if _, err := fmt.Fprintf(w, "data: %s\n\n", data); err != nil {
+				return nil
+			}
+			if f, ok := w.(http.Flusher); ok {
+				f.Flush()
+			}
+
+		case <-heartbeat.C:
+			// Send a heartbeat comment to keep the connection alive.
+			if _, err := fmt.Fprint(w, ": heartbeat\n\n"); err != nil {
+				return nil
+			}
+			if f, ok := w.(http.Flusher); ok {
+				f.Flush()
+			}
+		}
+	}
+}

server/router/api/v1/sse_hub.go

@@ -0,0 +1,98 @@
+package v1
+
+import (
+	"encoding/json"
+	"log/slog"
+	"sync"
+)
+
+// SSEEventType represents the type of change event.
+type SSEEventType string
+
+const (
+	SSEEventMemoCreated      SSEEventType = "memo.created"
+	SSEEventMemoUpdated      SSEEventType = "memo.updated"
+	SSEEventMemoDeleted      SSEEventType = "memo.deleted"
+	SSEEventReactionUpserted SSEEventType = "reaction.upserted"
+	SSEEventReactionDeleted  SSEEventType = "reaction.deleted"
+)
+
+// SSEEvent represents a change event sent to SSE clients.
+type SSEEvent struct {
+	Type SSEEventType `json:"type"`
+	// Name is the affected resource name (e.g., "memos/xxxx").
+	// For reaction events, this is the memo resource name that the reaction belongs to.
+	Name string `json:"name"`
+}
+
+// JSON returns the JSON representation of the event.
+// Returns nil if marshaling fails (error is logged).
+func (e *SSEEvent) JSON() []byte {
+	data, err := json.Marshal(e)
+	if err != nil {
+		slog.Error("failed to marshal SSE event", "err", err, "event", e)
+		return nil
+	}
+	return data
+}
+
+// SSEClient represents a single SSE connection.
+type SSEClient struct {
+	events chan []byte
+}
+
+// SSEHub manages SSE client connections and broadcasts events.
+// It is safe for concurrent use.
+type SSEHub struct {
+	mu      sync.RWMutex
+	clients map[*SSEClient]struct{}
+}
+
+// NewSSEHub creates a new SSE hub.
+func NewSSEHub() *SSEHub {
+	return &SSEHub{
+		clients: make(map[*SSEClient]struct{}),
+	}
+}
+
+// Subscribe registers a new client and returns it.
+// The caller must call Unsubscribe when done.
+func (h *SSEHub) Subscribe() *SSEClient {
+	c := &SSEClient{
+		// Buffer a few events so a slow client doesn't block broadcasting.
+		events: make(chan []byte, 32),
+	}
+	h.mu.Lock()
+	h.clients[c] = struct{}{}
+	h.mu.Unlock()
+	return c
+}
+
+// Unsubscribe removes a client and closes its channel.
+func (h *SSEHub) Unsubscribe(c *SSEClient) {
+	h.mu.Lock()
+	if _, ok := h.clients[c]; ok {
+		delete(h.clients, c)
+		close(c.events)
+	}
+	h.mu.Unlock()
+}
+
+// Broadcast sends an event to all connected clients.
+// Slow clients that have a full buffer will have the event dropped
+// to avoid blocking the broadcaster.
+func (h *SSEHub) Broadcast(event *SSEEvent) {
+	data := event.JSON()
+	if len(data) == 0 {
+		return
+	}
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+	for c := range h.clients {
+		select {
+		case c.events <- data:
+		default:
+			// Drop event for slow client to avoid blocking.
+		}
+	}
+}

server/router/api/v1/sse_hub_test.go

@@ -0,0 +1,70 @@
+package v1
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestSSEHub_SubscribeUnsubscribe(t *testing.T) {
+	hub := NewSSEHub()
+
+	client := hub.Subscribe()
+	require.NotNil(t, client)
+	require.NotNil(t, client.events)
+
+	// Unsubscribe removes the client and closes the channel.
+	hub.Unsubscribe(client)
+
+	// Channel should be closed.
+	_, ok := <-client.events
+	assert.False(t, ok, "channel should be closed after Unsubscribe")
+}
+
+func TestSSEHub_Broadcast(t *testing.T) {
+	hub := NewSSEHub()
+	client := hub.Subscribe()
+	defer hub.Unsubscribe(client)
+
+	event := &SSEEvent{Type: SSEEventMemoCreated, Name: "memos/123"}
+	hub.Broadcast(event)
+
+	select {
+	case data := <-client.events:
+		assert.Contains(t, string(data), `"type":"memo.created"`)
+		assert.Contains(t, string(data), `"name":"memos/123"`)
+	case <-time.After(time.Second):
+		t.Fatal("expected to receive event within 1s")
+	}
+}
+
+func TestSSEHub_BroadcastMultipleClients(t *testing.T) {
+	hub := NewSSEHub()
+	c1 := hub.Subscribe()
+	defer hub.Unsubscribe(c1)
+	c2 := hub.Subscribe()
+	defer hub.Unsubscribe(c2)
+
+	event := &SSEEvent{Type: SSEEventMemoDeleted, Name: "memos/456"}
+	hub.Broadcast(event)
+
+	for _, ch := range []chan []byte{c1.events, c2.events} {
+		select {
+		case data := <-ch:
+			assert.Contains(t, string(data), "memo.deleted")
+			assert.Contains(t, string(data), "memos/456")
+		case <-time.After(time.Second):
+			t.Fatal("expected to receive event within 1s")
+		}
+	}
+}
+
+func TestSSEEvent_JSON(t *testing.T) {
+	e := &SSEEvent{Type: SSEEventMemoUpdated, Name: "memos/789"}
+	data := e.JSON()
+	require.NotEmpty(t, data)
+	assert.Contains(t, string(data), `"type":"memo.updated"`)
+	assert.Contains(t, string(data), `"name":"memos/789"`)
+}

server/router/api/v1/test/sse_handler_test.go

@@ -0,0 +1,86 @@
+package test
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/labstack/echo/v5"
+	"github.com/stretchr/testify/require"
+
+	"github.com/usememos/memos/server/auth"
+	apiv1 "github.com/usememos/memos/server/router/api/v1"
+)
+
+func TestSSEHandler_Authentication(t *testing.T) {
+	ctx := context.Background()
+	ts := NewTestService(t)
+	defer ts.Cleanup()
+
+	user, err := ts.CreateRegularUser(ctx, "sse-user")
+	require.NoError(t, err)
+
+	token, _, err := auth.GenerateAccessTokenV2(
+		user.ID,
+		user.Username,
+		string(user.Role),
+		string(user.RowStatus),
+		[]byte(ts.Secret),
+	)
+	require.NoError(t, err)
+
+	e := echo.New()
+	apiv1.RegisterSSERoutes(e, ts.Service.SSEHub, ts.Store, ts.Secret)
+
+	t.Run("no token returns 401", func(t *testing.T) {
+		req := httptest.NewRequest(http.MethodGet, "/api/v1/sse", nil)
+		rec := httptest.NewRecorder()
+		e.ServeHTTP(rec, req)
+		require.Equal(t, http.StatusUnauthorized, rec.Code)
+	})
+
+	t.Run("invalid token returns 401", func(t *testing.T) {
+		req := httptest.NewRequest(http.MethodGet, "/api/v1/sse", nil)
+		req.Header.Set("Authorization", "Bearer invalid-token")
+		rec := httptest.NewRecorder()
+		e.ServeHTTP(rec, req)
+		require.Equal(t, http.StatusUnauthorized, rec.Code)
+	})
+
+	t.Run("valid token returns 200 and stream", func(t *testing.T) {
+		// Use a cancellable context so we can close the SSE connection after
+		// confirming the headers, preventing the handler's event loop from
+		// blocking the test indefinitely.
+		reqCtx, cancel := context.WithCancel(context.Background())
+		defer cancel()
+		req := httptest.NewRequest(http.MethodGet, "/api/v1/sse", nil).WithContext(reqCtx)
+		req.Header.Set("Authorization", "Bearer "+token)
+		rec := httptest.NewRecorder()
+		done := make(chan struct{})
+		go func() {
+			defer close(done)
+			e.ServeHTTP(rec, req)
+		}()
+		// Cancel the context to signal client disconnect, which exits the SSE loop.
+		cancel()
+		<-done
+		require.Equal(t, http.StatusOK, rec.Code)
+		require.Equal(t, "text/event-stream", rec.Header().Get("Content-Type"))
+	})
+
+	t.Run("token in query param returns 200", func(t *testing.T) {
+		reqCtx, cancel := context.WithCancel(context.Background())
+		defer cancel()
+		req := httptest.NewRequest(http.MethodGet, "/api/v1/sse?token="+token, nil).WithContext(reqCtx)
+		rec := httptest.NewRecorder()
+		done := make(chan struct{})
+		go func() {
+			defer close(done)
+			e.ServeHTTP(rec, req)
+		}()
+		cancel()
+		<-done
+		require.Equal(t, http.StatusOK, rec.Code)
+	})
+}

server/router/api/v1/test/test_helper.go

@@ -46,6 +46,7 @@ func NewTestService(t *testing.T) *TestService {
 		Profile:         testProfile,
 		Store:           testStore,
 		MarkdownService: markdownService,
+		SSEHub:          apiv1.NewSSEHub(),
 	}
 
 	return &TestService{

server/router/api/v1/v1.go

@@ -31,6 +31,7 @@ type APIV1Service struct {
 	Profile         *profile.Profile
 	Store           *store.Store
 	MarkdownService markdown.Service
+	SSEHub          *SSEHub
 
 	// thumbnailSemaphore limits concurrent thumbnail generation to prevent memory exhaustion
 	thumbnailSemaphore *semaphore.Weighted
@@ -45,6 +46,7 @@ func NewAPIV1Service(secret string, profile *profile.Profile, store *store.Store
 		Profile:            profile,
 		Store:              store,
 		MarkdownService:    markdownService,
+		SSEHub:             NewSSEHub(),
 		thumbnailSemaphore: semaphore.NewWeighted(3), // Limit to 3 concurrent thumbnail generations
 	}
 }
@@ -115,6 +117,10 @@ func (s *APIV1Service) RegisterGateway(ctx context.Context, echoServer *echo.Ech
 	gwGroup.Use(middleware.CORSWithConfig(middleware.CORSConfig{
 		AllowOrigins: []string{"*"},
 	}))
+	// Register SSE endpoint with same CORS as rest of /api/v1.
+	gwGroup.GET("/api/v1/sse", func(c *echo.Context) error {
+		return handleSSE(c, s.SSEHub, auth.NewAuthenticator(s.Store, s.Secret))
+	})
 	handler := echo.WrapHandler(gwMux)
 
 	gwGroup.Any("/api/v1/*", handler)

server/router/fileserver/README.md

@@ -184,7 +184,7 @@ Parses data URI to extract MIME type and base64 data.
 ## Dependencies
 
 ### External Packages
-- `github.com/labstack/echo/v4` - HTTP router and middleware
+- `github.com/labstack/echo/v5` - HTTP router and middleware
 - `github.com/golang-jwt/jwt/v5` - JWT parsing and validation
 - `github.com/disintegration/imaging` - Image thumbnail generation
 - `golang.org/x/sync/semaphore` - Concurrency control for thumbnails

server/server.go

@@ -75,7 +75,8 @@ func NewServer(ctx context.Context, profile *profile.Profile, store *store.Store
 
 	// Create and register RSS routes (needs markdown service from apiV1Service).
 	rss.NewRSSService(s.Profile, s.Store, apiV1Service.MarkdownService).RegisterRoutes(rootGroup)
-	// Register gRPC gateway as api v1.
+
+	// Register gRPC gateway as api v1 (includes SSE endpoint on CORS-enabled group).
 	if err := apiV1Service.RegisterGateway(ctx, echoServer); err != nil {
 		return nil, errors.Wrap(err, "failed to register gRPC gateway")
 	}

web/src/components/Navigation.tsx

@@ -8,6 +8,7 @@ import { Routes } from "@/router";
 import { UserNotification_Status } from "@/types/proto/api/v1/user_service_pb";
 import { useTranslate } from "@/utils/i18n";
 import MemosLogo from "./MemosLogo";
+import SSEStatusIndicator from "./SSEStatusIndicator";
 import UserMenu from "./UserMenu";
 
 interface NavLinkItem {
@@ -114,7 +115,10 @@ const Navigation = (props: Props) => {
         ))}
       </div>
       {currentUser && (
-        <div className={cn("w-full flex flex-col justify-end", props.collapsed ? "items-center" : "items-start pl-3")}>
+        <div className={cn("w-full flex flex-col justify-end gap-1", props.collapsed ? "items-center" : "items-start pl-3")}>
+          <div className={cn("flex items-center", props.collapsed ? "justify-center" : "pl-1")}>
+            <SSEStatusIndicator />
+          </div>
           <UserMenu collapsed={collapsed} />
         </div>
       )}

web/src/components/SSEStatusIndicator.tsx

@@ -0,0 +1,36 @@
+import { useSSEConnectionStatus } from "@/hooks/useLiveMemoRefresh";
+import { cn } from "@/lib/utils";
+import { Tooltip, TooltipContent, TooltipTrigger } from "./ui/tooltip";
+
+/**
+ * A small colored dot that indicates the SSE live-refresh connection status.
+ * - Green = connected (live updates active)
+ * - Yellow/pulsing = connecting
+ * - Red = disconnected (updates not live)
+ */
+const SSEStatusIndicator = () => {
+  const status = useSSEConnectionStatus();
+
+  const label =
+    status === "connected" ? "Live updates active" : status === "connecting" ? "Connecting to live updates..." : "Live updates unavailable";
+
+  return (
+    <Tooltip>
+      <TooltipTrigger asChild>
+        <span className="inline-flex items-center justify-center size-5 cursor-default" aria-label={label}>
+          <span
+            className={cn(
+              "block size-2 rounded-full transition-colors",
+              status === "connected" && "bg-green-500",
+              status === "connecting" && "bg-yellow-500 animate-pulse",
+              status === "disconnected" && "bg-red-500",
+            )}
+          />
+        </span>
+      </TooltipTrigger>
+      <TooltipContent>{label}</TooltipContent>
+    </Tooltip>
+  );
+};
+
+export default SSEStatusIndicator;

web/src/hooks/useLiveMemoRefresh.ts

@@ -0,0 +1,204 @@
+import { useQueryClient } from "@tanstack/react-query";
+import { useCallback, useEffect, useRef, useSyncExternalStore } from "react";
+import { getAccessToken } from "@/auth-state";
+import { useAuth } from "@/contexts/AuthContext";
+import { memoKeys } from "@/hooks/useMemoQueries";
+import { userKeys } from "@/hooks/useUserQueries";
+
+/**
+ * Reconnection parameters for SSE connection.
+ */
+const INITIAL_RETRY_DELAY_MS = 1000;
+const MAX_RETRY_DELAY_MS = 30000;
+const RETRY_BACKOFF_MULTIPLIER = 2;
+
+// ---------------------------------------------------------------------------
+// Shared connection status store (singleton)
+// ---------------------------------------------------------------------------
+
+export type SSEConnectionStatus = "connected" | "disconnected" | "connecting";
+
+type Listener = () => void;
+
+let _status: SSEConnectionStatus = "disconnected";
+const _listeners = new Set<Listener>();
+
+function getSSEStatus(): SSEConnectionStatus {
+  return _status;
+}
+
+function setSSEStatus(s: SSEConnectionStatus) {
+  if (_status !== s) {
+    _status = s;
+    _listeners.forEach((l) => l());
+  }
+}
+
+function subscribeSSEStatus(listener: Listener): () => void {
+  _listeners.add(listener);
+  return () => _listeners.delete(listener);
+}
+
+/**
+ * React hook that returns the current SSE connection status.
+ * Re-renders the component whenever the status changes.
+ */
+export function useSSEConnectionStatus(): SSEConnectionStatus {
+  return useSyncExternalStore(subscribeSSEStatus, getSSEStatus, getSSEStatus);
+}
+
+// ---------------------------------------------------------------------------
+// Main hook
+// ---------------------------------------------------------------------------
+
+/**
+ * useLiveMemoRefresh connects to the server's SSE endpoint and
+ * invalidates relevant React Query caches when change events
+ * (memos, reactions) are received.
+ *
+ * This enables real-time updates across all open instances of the app.
+ */
+export function useLiveMemoRefresh() {
+  const queryClient = useQueryClient();
+  const { currentUser } = useAuth();
+  const retryDelayRef = useRef(INITIAL_RETRY_DELAY_MS);
+  const abortControllerRef = useRef<AbortController | null>(null);
+
+  const handleEvent = useCallback((event: SSEChangeEvent) => handleSSEEvent(event, queryClient), [queryClient]);
+
+  useEffect(() => {
+    let mounted = true;
+    let retryTimeout: ReturnType<typeof setTimeout> | null = null;
+
+    const connect = async () => {
+      if (!mounted) return;
+
+      const token = getAccessToken();
+      if (!token) {
+        setSSEStatus("disconnected");
+        // Not logged in; do not retry. Effect will re-run when currentUser is set (login).
+        return;
+      }
+
+      setSSEStatus("connecting");
+      const abortController = new AbortController();
+      abortControllerRef.current = abortController;
+
+      try {
+        const response = await fetch("/api/v1/sse", {
+          headers: {
+            Authorization: `Bearer ${token}`,
+          },
+          signal: abortController.signal,
+          credentials: "include",
+        });
+
+        if (!response.ok || !response.body) {
+          throw new Error(`SSE connection failed: ${response.status}`);
+        }
+
+        // Successfully connected - reset retry delay.
+        retryDelayRef.current = INITIAL_RETRY_DELAY_MS;
+        setSSEStatus("connected");
+
+        const reader = response.body.getReader();
+        const decoder = new TextDecoder();
+        let buffer = "";
+
+        while (mounted) {
+          const { done, value } = await reader.read();
+          if (done) break;
+
+          buffer += decoder.decode(value, { stream: true });
+
+          // Process complete SSE messages (separated by double newlines).
+          const messages = buffer.split("\n\n");
+          // Keep the last incomplete chunk in the buffer.
+          buffer = messages.pop() || "";
+
+          for (const message of messages) {
+            if (!message.trim()) continue;
+
+            // Parse SSE format: lines starting with "data: " contain JSON payload.
+            // Lines starting with ":" are comments (heartbeats).
+            for (const line of message.split("\n")) {
+              if (line.startsWith("data: ")) {
+                const jsonStr = line.slice(6);
+                try {
+                  const event = JSON.parse(jsonStr) as SSEChangeEvent;
+                  handleEvent(event);
+                } catch {
+                  // Ignore malformed JSON.
+                }
+              }
+            }
+          }
+        }
+      } catch (err: unknown) {
+        if (err instanceof DOMException && err.name === "AbortError") {
+          // Intentional abort, don't reconnect.
+          setSSEStatus("disconnected");
+          return;
+        }
+        // Connection lost or failed - reconnect with backoff.
+      }
+
+      setSSEStatus("disconnected");
+
+      // Reconnect with exponential backoff.
+      if (mounted) {
+        const delay = retryDelayRef.current;
+        retryDelayRef.current = Math.min(delay * RETRY_BACKOFF_MULTIPLIER, MAX_RETRY_DELAY_MS);
+        retryTimeout = setTimeout(connect, delay);
+      }
+    };
+
+    connect();
+
+    return () => {
+      mounted = false;
+      setSSEStatus("disconnected");
+      if (retryTimeout) {
+        clearTimeout(retryTimeout);
+      }
+      if (abortControllerRef.current) {
+        abortControllerRef.current.abort();
+      }
+    };
+  }, [handleEvent, currentUser]);
+}
+
+// ---------------------------------------------------------------------------
+// Event handling
+// ---------------------------------------------------------------------------
+
+interface SSEChangeEvent {
+  type: string;
+  name: string;
+}
+
+function handleSSEEvent(event: SSEChangeEvent, queryClient: ReturnType<typeof useQueryClient>) {
+  switch (event.type) {
+    case "memo.created":
+      queryClient.invalidateQueries({ queryKey: memoKeys.lists() });
+      queryClient.invalidateQueries({ queryKey: userKeys.stats() });
+      break;
+
+    case "memo.updated":
+      queryClient.invalidateQueries({ queryKey: memoKeys.detail(event.name) });
+      queryClient.invalidateQueries({ queryKey: memoKeys.lists() });
+      break;
+
+    case "memo.deleted":
+      queryClient.removeQueries({ queryKey: memoKeys.detail(event.name) });
+      queryClient.invalidateQueries({ queryKey: memoKeys.lists() });
+      queryClient.invalidateQueries({ queryKey: userKeys.stats() });
+      break;
+
+    case "reaction.upserted":
+    case "reaction.deleted":
+      queryClient.invalidateQueries({ queryKey: memoKeys.detail(event.name) });
+      queryClient.invalidateQueries({ queryKey: memoKeys.lists() });
+      break;
+  }
+}

web/src/main.tsx

@@ -12,6 +12,7 @@ import { refreshAccessToken } from "@/connect";
 import { AuthProvider, useAuth } from "@/contexts/AuthContext";
 import { InstanceProvider, useInstance } from "@/contexts/InstanceContext";
 import { ViewProvider } from "@/contexts/ViewContext";
+import { useLiveMemoRefresh } from "@/hooks/useLiveMemoRefresh";
 import { useTokenRefreshOnFocus } from "@/hooks/useTokenRefreshOnFocus";
 import { queryClient } from "@/lib/query-client";
 import router from "./router";
@@ -46,6 +47,9 @@ function AppInitializer({ children }: { children: React.ReactNode }) {
   // Related: https://github.com/usememos/memos/issues/5589
   useTokenRefreshOnFocus(refreshAccessToken, !!currentUser);
 
+  // Live refresh: listen for memo changes via SSE and invalidate caches.
+  useLiveMemoRefresh();
+
   if (!authInitialized || !instanceInitialized) {
     return null;
   }

web/vite.config.mts

@@ -16,6 +16,12 @@ export default defineConfig({
     host: "0.0.0.0",
     port: 3001,
     proxy: {
+      "^/api/v1/sse": {
+        target: devProxyServer,
+        xfwd: true,
+        // SSE requires no response buffering and longer timeout.
+        timeout: 0,
+      },
       "^/api": {
         target: devProxyServer,
         xfwd: true,