diff --git a/src/attach.ts b/src/attach.ts
index caae1264..6ed3f549 100644
--- a/src/attach.ts
+++ b/src/attach.ts
@@ -59,7 +59,7 @@ export const attachSockets = async <NS extends Namespaces>({
     const emitCfg: EmitterConfig<NSEmissions> = { emission, timeout };
     const nsCtx: IndependentContext<NSEmissions, NSMeta> = {
       logger: rootLogger,
-      withRooms: makeRoomService({ subject: io, metadata, ...emitCfg }),
+      withRooms: makeRoomService({ subject: ns, metadata, ...emitCfg }),
       all: {
         getClients: async () =>
           makeRemoteClients({
@@ -68,7 +68,7 @@ export const attachSockets = async <NS extends Namespaces>({
             ...emitCfg,
           }),
         getRooms: () => Array.from(ns.adapter.rooms.keys()),
-        broadcast: makeEmitter({ subject: io, ...emitCfg }),
+        broadcast: makeEmitter({ subject: ns, ...emitCfg }),
       },
     };
     ns.on("connection", async (socket) => {
diff --git a/src/emission.ts b/src/emission.ts
index 24c342c6..d9718327 100644
--- a/src/emission.ts
+++ b/src/emission.ts
@@ -58,14 +58,16 @@ export function makeEmitter<E extends EmissionMap>(
   } & EmitterConfig<E>,
 ): Emitter<E>;
 export function makeEmitter<E extends EmissionMap>(
-  props: { subject: Socket["broadcast"] | Server } & EmitterConfig<E>,
+  props: {
+    subject: Socket["broadcast"] | Server | Namespace;
+  } & EmitterConfig<E>,
 ): Broadcaster<E>;
 export function makeEmitter({
   subject,
   emission,
   timeout,
 }: {
-  subject: Socket | SomeRemoteSocket | Socket["broadcast"] | Server;
+  subject: Socket | SomeRemoteSocket | Namespace | Socket["broadcast"] | Server;
 } & EmitterConfig<EmissionMap>) {
   /**
    * @throws z.ZodError on validation
diff --git a/tests/system/issue590.spec.ts b/tests/system/issue590.spec.ts
index ee5103da..7b510b87 100644
--- a/tests/system/issue590.spec.ts
+++ b/tests/system/issue590.spec.ts
@@ -2,7 +2,7 @@ import http from "node:http";
 import { Server } from "socket.io";
 import { io as ioClient } from "socket.io-client";
 import { z } from "zod";
-import { attachSockets, Config, ActionsFactory } from "../../src";
+import { ActionsFactory, attachSockets, Config } from "../../src";
 import { promisify } from "node:util";
 import assert from "node:assert/strict";
 
@@ -17,6 +17,11 @@ const port = 8999;
  */
 describe("Issue #590", () => {
   describe("attachSockets() with real Socket.IO", () => {
+    let intervalRef: NodeJS.Timeout | undefined;
+    afterEach(() => {
+      if (intervalRef) clearInterval(intervalRef);
+    });
+
     test("should query and broadcast to rooms joined in onConnection", async () => {
       const httpServer = http.createServer();
       const io = new Server();
@@ -81,6 +86,119 @@ describe("Issue #590", () => {
       // withRooms().broadcast() should reach client:
       expect(receivedBroadcast).toBe("hello");
 
+      clientSocket.disconnect();
+      await promisify(io.close.bind(io))();
+      if (httpServer.listening)
+        await promisify(httpServer.close.bind(httpServer))();
+    });
+    test("should broadcast to all from startup hook using all.broadcast", async () => {
+      const httpServer = http.createServer();
+      const io = new Server();
+
+      const config = new Config().addNamespace({
+        path: "/chat",
+        emission: {
+          testBroadcast: { schema: z.tuple([z.string()]) },
+        },
+        hooks: {
+          onConnection: async ({ client }) => {
+            await client.join("testRoom");
+          },
+          onStartup: async ({ all }) => {
+            intervalRef = setInterval(() => {
+              all.broadcast("testBroadcast", "from onStartup hook");
+            }, 100);
+          },
+        },
+        metadata: z.object({}),
+      });
+
+      await attachSockets({
+        io,
+        config,
+        actions: [],
+        target: httpServer,
+      });
+
+      await promisify(httpServer.listen.bind(httpServer, port))();
+
+      // connect client:
+      const clientSocket = ioClient(`http://localhost:${port}/chat`, {
+        transports: ["websocket"],
+      });
+
+      await vi.waitFor(() => assert(clientSocket.connected));
+
+      // listen for broadcast:
+      const broadcastReceived = new Promise<string>((resolve) => {
+        clientSocket.on("testBroadcast", resolve);
+      });
+
+      const receivedBroadcast = await vi.waitFor(() => broadcastReceived, {
+        timeout: 1000,
+      });
+
+      // all.broadcast() should reach client:
+      expect(receivedBroadcast).toBe("from onStartup hook");
+
+      clientSocket.disconnect();
+      await promisify(io.close.bind(io))();
+      if (httpServer.listening)
+        await promisify(httpServer.close.bind(httpServer))();
+    });
+    test("should broadcast to rooms from startup hook using withRooms", async () => {
+      const httpServer = http.createServer();
+      const io = new Server();
+
+      const config = new Config().addNamespace({
+        path: "/chat",
+        emission: {
+          testBroadcast: { schema: z.tuple([z.string()]) },
+        },
+        hooks: {
+          onConnection: async ({ client }) => {
+            await client.join("testRoom");
+          },
+          onStartup: async ({ withRooms }) => {
+            intervalRef = setInterval(() => {
+              withRooms("testRoom").broadcast(
+                "testBroadcast",
+                "from onStartup hook",
+              );
+            }, 100);
+          },
+        },
+        metadata: z.object({}),
+      });
+
+      await attachSockets({
+        io,
+        config,
+        actions: [],
+        target: httpServer,
+      });
+
+      await promisify(httpServer.listen.bind(httpServer, port))();
+
+      // connect client:
+      const clientSocket = ioClient(`http://localhost:${port}/chat`, {
+        transports: ["websocket"],
+      });
+
+      await vi.waitFor(() => assert(clientSocket.connected));
+
+      // listen for broadcast:
+      const broadcastReceived = new Promise<string>((resolve) => {
+        clientSocket.on("testBroadcast", resolve);
+      });
+
+      const receivedBroadcast = await vi.waitFor(() => broadcastReceived, {
+        timeout: 1000,
+      });
+
+      // withRooms().broadcast() should reach client:
+      expect(receivedBroadcast).toBe("from onStartup hook");
+
       clientSocket.disconnect();
       await promisify(io.close.bind(io))();
       if (httpServer.listening)