diff --git a/.changeset/amsg-vapid-public-key.md b/.changeset/amsg-vapid-public-key.md
new file mode 100644
index 0000000..b275e56
--- /dev/null
+++ b/.changeset/amsg-vapid-public-key.md
@@ -0,0 +1,9 @@
+---
+"@rei-standard/amsg-server": minor
+"@rei-standard/amsg-client": minor
+---
+
+单用户 worker 暴露 VAPID 公钥端点，供前端跨源订阅。
+
+- amsg-server：单用户 Worker 新增 `GET /vapid-public-key`，返回本 Worker 自己的 `VAPID_PUBLIC_KEY`（未配置时返回 503 `VAPID_NOT_CONFIGURED`）。和其它端点共用同一套 CORS 与 `serverToken` 校验。前端拿它作为 `applicationServerKey` 来创建 Web Push 订阅——各自部署的 worker 各有各的 VAPID，公钥在运行时从 worker 拉取。
+- amsg-client：新增 `ReiClient.getVapidPublicKey()`，GET 该端点并返回公钥字符串（配了 `serverToken` 时带上 `X-Client-Token`）。
diff --git a/packages/rei-standard-amsg/client/src/index.js b/packages/rei-standard-amsg/client/src/index.js
index 1ba520d..43683ee 100644
--- a/packages/rei-standard-amsg/client/src/index.js
+++ b/packages/rei-standard-amsg/client/src/index.js
@@ -440,6 +440,28 @@ export class ReiClient {
     this._userKey = this._hexToUint8Array(userKey);
   }
 
+  /**
+   * Fetch the amsg-server worker's own VAPID public key.
+   *
+   * A browser needs this as `applicationServerKey` when creating a Web Push
+   * subscription. Each self-hosted worker owns its VAPID keypair, so pull the
+   * key at runtime rather than baking it into the frontend. Sends
+   * `X-Client-Token` when a `serverToken` is configured.
+   *
+   * @returns {Promise<string>} The base64url VAPID public key.
+   * @throws {Error} When the worker has no VAPID public key configured (503).
+   */
+  async getVapidPublicKey() {
+    const res = await fetch(`${this._baseUrl}/vapid-public-key`, {
+      method: 'GET',
+      headers: this._withServerToken({})
+    });
+
+    const json = await res.json();
+    if (!json.success) throw new Error(json.error?.message || 'Failed to fetch VAPID public key');
+    return json.publicKey;
+  }
+
   // ─── Public API ─────────────────────────────────────────────────
 
   /**
diff --git a/packages/rei-standard-amsg/client/test/vapid-public-key.test.mjs b/packages/rei-standard-amsg/client/test/vapid-public-key.test.mjs
new file mode 100644
index 0000000..cc2dd2f
--- /dev/null
+++ b/packages/rei-standard-amsg/client/test/vapid-public-key.test.mjs
@@ -0,0 +1,60 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { ReiClient } from '../src/index.js';
+
+const USER = '550e8400-e29b-41d4-a716-446655440000';
+
+test('getVapidPublicKey() GETs /vapid-public-key with X-Client-Token and returns the key string', async () => {
+  const captured = [];
+  const original = globalThis.fetch;
+  globalThis.fetch = async (url, init) => {
+    captured.push({ url: String(url), method: init && init.method, headers: (init && init.headers) || {} });
+    return new Response(JSON.stringify({ success: true, publicKey: 'BPUB123' }), {
+      status: 200, headers: { 'Content-Type': 'application/json' }
+    });
+  };
+  let key;
+  try {
+    const client = new ReiClient({ baseUrl: 'https://w.dev', userId: USER, serverToken: 's3cret' });
+    key = await client.getVapidPublicKey();
+  } finally {
+    globalThis.fetch = original;
+  }
+  assert.equal(captured.length, 1);
+  assert.equal(captured[0].url, 'https://w.dev/vapid-public-key');
+  assert.equal(captured[0].method, 'GET');
+  assert.equal(captured[0].headers['X-Client-Token'], 's3cret');
+  assert.equal(key, 'BPUB123');
+});
+
+test('getVapidPublicKey() without serverToken sends no X-Client-Token', async () => {
+  const captured = [];
+  const original = globalThis.fetch;
+  globalThis.fetch = async (url, init) => {
+    captured.push({ headers: (init && init.headers) || {} });
+    return new Response(JSON.stringify({ success: true, publicKey: 'BPUB123' }), {
+      status: 200, headers: { 'Content-Type': 'application/json' }
+    });
+  };
+  try {
+    const client = new ReiClient({ baseUrl: 'https://w.dev', userId: USER });
+    await client.getVapidPublicKey();
+  } finally {
+    globalThis.fetch = original;
+  }
+  assert.equal(captured[0].headers['X-Client-Token'], undefined);
+});
+
+test('getVapidPublicKey() throws on a non-success response', async () => {
+  const original = globalThis.fetch;
+  globalThis.fetch = async () => new Response(
+    JSON.stringify({ success: false, error: { code: 'VAPID_NOT_CONFIGURED', message: 'VAPID 未配置' } }),
+    { status: 503, headers: { 'Content-Type': 'application/json' } }
+  );
+  try {
+    const client = new ReiClient({ baseUrl: 'https://w.dev', userId: USER });
+    await assert.rejects(() => client.getVapidPublicKey(), /VAPID 未配置/);
+  } finally {
+    globalThis.fetch = original;
+  }
+});
diff --git a/packages/rei-standard-amsg/server/examples/cloudflare-single-user/README.md b/packages/rei-standard-amsg/server/examples/cloudflare-single-user/README.md
index 2d175b2..44902cc 100644
--- a/packages/rei-standard-amsg/server/examples/cloudflare-single-user/README.md
+++ b/packages/rei-standard-amsg/server/examples/cloudflare-single-user/README.md
@@ -27,9 +27,11 @@
 
 ## 端点
 
-`/get-user-key`、`/schedule-message`、`/messages`、`/update-message`、`/cancel-message`、`/init-tenant`。
+`/get-user-key`、`/schedule-message`、`/messages`、`/update-message`、`/cancel-message`、`/init-tenant`、`/vapid-public-key`。
 **没有 HTTP `/send-notifications`**——定时投递由 CF Cron Trigger 直接触发 `scheduled()`。
 
+`GET /vapid-public-key` 返回本 Worker 的 `VAPID_PUBLIC_KEY`，供前端创建 Web Push 订阅时作 `applicationServerKey`；未配置 VAPID 时返回 503。跟其它端点一样受 CORS 和 `serverToken` 约束。
+
 VAPID 和 webpush 都要配齐：定时投递（cron）和 `instant` 类型消息都靠它推送，缺了就发不出去。
 
 ## 导入入口
diff --git a/packages/rei-standard-amsg/server/src/server/cloudflare/single-user-worker.js b/packages/rei-standard-amsg/server/src/server/cloudflare/single-user-worker.js
index 98ad210..d85b9c3 100644
--- a/packages/rei-standard-amsg/server/src/server/cloudflare/single-user-worker.js
+++ b/packages/rei-standard-amsg/server/src/server/cloudflare/single-user-worker.js
@@ -12,6 +12,8 @@
  *   GET  /messages          → list
  *   PUT  /update-message    → patch
  *   DELETE /cancel-message  → delete
+ *   GET  /vapid-public-key  → this worker's VAPID public key (for the frontend's
+ *                             Web Push subscription); 503 if VAPID_PUBLIC_KEY unset
  *
  * CORS is opt-in: pass `cors: { origin }` in the config (a fixed origin, '*', or
  * an (origin) => allowedOrigin function) to answer OPTIONS preflights and echo
@@ -111,6 +113,8 @@ export function createSingleUserCloudflareWorker(buildConfig) {
         result = await server.handlers.updateMessage.PUT(url, headers, await request.text());
       } else if (method === 'DELETE' && pathname.endsWith('/cancel-message')) {
         result = await server.handlers.cancelMessage.DELETE(url, headers);
+      } else if (method === 'GET' && pathname.endsWith('/vapid-public-key')) {
+        result = await server.handlers.vapidPublicKey.GET(url, headers);
       } else {
         result = { status: 404, body: { success: false, error: { code: 'NOT_FOUND', message: 'Unknown route' } } };
       }
diff --git a/packages/rei-standard-amsg/server/src/server/handlers/vapid-public-key.js b/packages/rei-standard-amsg/server/src/server/handlers/vapid-public-key.js
new file mode 100644
index 0000000..b5ed306
--- /dev/null
+++ b/packages/rei-standard-amsg/server/src/server/handlers/vapid-public-key.js
@@ -0,0 +1,47 @@
+/**
+ * Handler: vapid-public-key
+ *
+ * Exposes this worker's own VAPID public key so a browser frontend can build a
+ * Web Push subscription (`applicationServerKey`) at runtime. Each self-hosted
+ * worker owns its keypair, so the key can't be baked into the frontend — it
+ * pulls it from here.
+ *
+ * Auth funnels through the same resolveTenant as every other endpoint, so with
+ * a serverToken configured this route requires `X-Client-Token` too (the
+ * all-or-nothing contract). The public key itself is not a secret; gating it
+ * just keeps every endpoint consistent.
+ *
+ * @param {Object} ctx - Server context ({ vapid, tenantManager, ... }).
+ * @returns {{ GET: function }}
+ */
+
+export function createVapidPublicKeyHandler(ctx) {
+  async function GET(url, headers) {
+    const effectiveHeaders = headers || url || {};
+    const tenantResult = await ctx.tenantManager.resolveTenant(effectiveHeaders);
+    if (!tenantResult.ok) {
+      return tenantResult.error;
+    }
+
+    const publicKey = ctx.vapid && ctx.vapid.publicKey;
+    if (!publicKey) {
+      return {
+        status: 503,
+        body: {
+          success: false,
+          error: {
+            code: 'VAPID_NOT_CONFIGURED',
+            message: 'VAPID 公钥未配置：请为本 Worker 设置 VAPID_PUBLIC_KEY'
+          }
+        }
+      };
+    }
+
+    return {
+      status: 200,
+      body: { success: true, publicKey }
+    };
+  }
+
+  return { GET };
+}
diff --git a/packages/rei-standard-amsg/server/src/server/single-user.js b/packages/rei-standard-amsg/server/src/server/single-user.js
index 97d6b7b..7254742 100644
--- a/packages/rei-standard-amsg/server/src/server/single-user.js
+++ b/packages/rei-standard-amsg/server/src/server/single-user.js
@@ -23,6 +23,7 @@ import { createScheduleMessageHandler } from './handlers/schedule-message.js';
 import { createUpdateMessageHandler } from './handlers/update-message.js';
 import { createCancelMessageHandler } from './handlers/cancel-message.js';
 import { createMessagesHandler } from './handlers/messages.js';
+import { createVapidPublicKeyHandler } from './handlers/vapid-public-key.js';
 
 export function createSingleUserServer(config) {
   if (!config || !config.db) throw new Error('[amsg-server single-user] config.db is required');
@@ -53,7 +54,8 @@ export function createSingleUserServer(config) {
       scheduleMessage: createScheduleMessageHandler(ctx),
       updateMessage: createUpdateMessageHandler(ctx),
       cancelMessage: createCancelMessageHandler(ctx),
-      messages: createMessagesHandler(ctx)
+      messages: createMessagesHandler(ctx),
+      vapidPublicKey: createVapidPublicKeyHandler(ctx)
     }
   };
 }
diff --git a/packages/rei-standard-amsg/server/test/single-user-worker.test.mjs b/packages/rei-standard-amsg/server/test/single-user-worker.test.mjs
index 35691a8..3e610ea 100644
--- a/packages/rei-standard-amsg/server/test/single-user-worker.test.mjs
+++ b/packages/rei-standard-amsg/server/test/single-user-worker.test.mjs
@@ -3,6 +3,7 @@ import assert from 'node:assert/strict';
 import { createSingleUserCloudflareWorker } from '../src/server/cloudflare/single-user-worker.js';
 import { createTestD1 } from './helpers/sqlite-d1.mjs';
 import { createD1Adapter } from '../src/server/adapters/d1.js';
+import { createWebCryptoWebPush } from '../src/server/lib/webpush-webcrypto.js';
 import { deriveUserEncryptionKey, encryptPayload, encryptForStorage } from '../src/server/lib/encryption.js';
 
 const USER = '550e8400-e29b-41d4-a716-446655440000';
@@ -184,7 +185,8 @@ test('serverToken set → every exposed route rejects wrong/missing token with 4
     ['POST', 'https://w.dev/schedule-message'],
     ['GET', 'https://w.dev/messages?status=all'],
     ['PUT', 'https://w.dev/update-message?id=x'],
-    ['DELETE', 'https://w.dev/cancel-message?id=x']
+    ['DELETE', 'https://w.dev/cancel-message?id=x'],
+    ['GET', 'https://w.dev/vapid-public-key']
   ];
 
   for (const [method, url] of routes) {
@@ -201,3 +203,159 @@ test('serverToken set → every exposed route rejects wrong/missing token with 4
     assert.equal(missing.status, 401, `${method} ${url} with no token must be 401`);
   }
 });
+
+// ─── GET /vapid-public-key ─────────────────────────────────────────────────
+// The frontend needs THIS worker's own VAPID public key at runtime to build a
+// Web Push subscription (applicationServerKey). Each self-hosted worker owns its
+// keypair, so the key can't be baked into the frontend — it pulls it from here.
+
+// A real P-256 keypair, so the push-signing path (buildVapidJwt) runs for real.
+// Needed to prove the endpoint hands back the very key that signs pushes.
+async function genVapid() {
+  const kp = await globalThis.crypto.subtle.generateKey({ name: 'ECDSA', namedCurve: 'P-256' }, true, ['sign', 'verify']);
+  const pub = new Uint8Array(await globalThis.crypto.subtle.exportKey('raw', kp.publicKey));
+  const jwk = await globalThis.crypto.subtle.exportKey('jwk', kp.privateKey);
+  const b64url = (u8) => Buffer.from(u8).toString('base64url');
+  return { publicKey: b64url(pub), privateKey: Buffer.from(jwk.d, 'base64url').toString('base64url') };
+}
+
+// A real subscriber keypair, so the aes128gcm encryption path runs (a fake
+// p256dh would throw before push signing ever puts the key on the wire).
+async function genSubscription() {
+  const kp = await globalThis.crypto.subtle.generateKey({ name: 'ECDH', namedCurve: 'P-256' }, true, ['deriveBits']);
+  const raw = new Uint8Array(await globalThis.crypto.subtle.exportKey('raw', kp.publicKey));
+  const auth = globalThis.crypto.getRandomValues(new Uint8Array(16));
+  const b64url = (u8) => Buffer.from(u8).toString('base64url');
+  return { endpoint: 'https://push.example.com/sub/abc', keys: { p256dh: b64url(raw), auth: b64url(auth) } };
+}
+
+test('GET /vapid-public-key returns the configured public key', async () => {
+  const d1 = createTestD1();
+  const worker = makeWorker(d1); // vapid.publicKey === 'pub', no serverToken
+  const res = await worker.fetch(new Request('https://w.dev/vapid-public-key', { method: 'GET' }), { DB: d1 });
+  assert.equal(res.status, 200);
+  const body = await res.json();
+  assert.equal(body.success, true);
+  assert.equal(body.publicKey, 'pub');
+});
+
+// Anti-divergence guard: the endpoint reads cfg.vapid.publicKey while push
+// signing reads cfg.webpush — two separate config fields that COULD drift. If
+// they ever point at different keys, the frontend subscribes with a key this
+// worker can't sign for and every push 403s. Pin them to the same value.
+test('the exposed VAPID public key is the same key push signing actually uses', async () => {
+  const { publicKey, privateKey } = await genVapid();
+  const email = 'mailto:x@example.com';
+  const sub = await genSubscription();
+
+  const d1 = createTestD1();
+  const adapter = createD1Adapter(d1);
+  await adapter.initSchema();
+  const userKey = deriveUserEncryptionKey(USER, MASTER_KEY);
+  const enc = encryptForStorage(JSON.stringify({
+    contactName: 'Rei', messageType: 'fixed', userMessage: 'hi', recurrenceType: 'none',
+    pushSubscription: sub
+  }), userKey);
+  await adapter.createTask({ user_id: USER, uuid: 'due', encrypted_payload: enc, next_send_at: '2020-01-01T00:00:00.000Z', message_type: 'fixed' });
+
+  const worker = createSingleUserCloudflareWorker(() => ({
+    db: adapter,
+    masterKey: MASTER_KEY,
+    vapid: { email, publicKey, privateKey },
+    webpush: createWebCryptoWebPush({ email, publicKey, privateKey })
+  }));
+  const env = { DB: d1 };
+
+  // 1) what the endpoint hands the frontend
+  const res = await worker.fetch(new Request('https://w.dev/vapid-public-key', { method: 'GET' }), env);
+  const endpointKey = (await res.json()).publicKey;
+
+  // 2) what push signing puts on the wire: `Authorization: vapid t=<jwt>, k=<publicKey>`
+  let wireKey = null;
+  const original = globalThis.fetch;
+  globalThis.fetch = async (_url, init) => {
+    const authz = (init.headers && (init.headers['Authorization'] || init.headers['authorization'])) || '';
+    const m = /k=([^,\s]+)/.exec(authz);
+    if (m) wireKey = m[1];
+    return new Response(null, { status: 201 });
+  };
+  try {
+    await worker.scheduled({}, env);
+  } finally {
+    globalThis.fetch = original;
+  }
+
+  assert.equal(endpointKey, publicKey);
+  assert.ok(wireKey, 'push signing put a k= on the wire');
+  assert.equal(endpointKey, wireKey);
+});
+
+test('GET /vapid-public-key → 503 VAPID_NOT_CONFIGURED when no public key is set', async () => {
+  const d1 = createTestD1();
+  const worker = createSingleUserCloudflareWorker((env) => ({
+    db: createD1Adapter(env.DB),
+    masterKey: MASTER_KEY,
+    vapid: { email: 'mailto:x@example.com', privateKey: 'priv' }, // publicKey absent
+    webpush: { async sendNotification() {} }
+  }));
+  const res = await worker.fetch(new Request('https://w.dev/vapid-public-key', { method: 'GET' }), { DB: d1 });
+  assert.equal(res.status, 503);
+  const body = await res.json();
+  assert.equal(body.success, false);
+  assert.equal(body.error.code, 'VAPID_NOT_CONFIGURED');
+});
+
+test('GET /vapid-public-key honours serverToken: right token → 200, wrong/missing → 401', async () => {
+  const d1 = createTestD1();
+  const worker = createSingleUserCloudflareWorker(() => ({
+    db: createD1Adapter(d1),
+    masterKey: MASTER_KEY,
+    serverToken: 's3cret',
+    vapid: { email: 'mailto:x@example.com', publicKey: 'pub', privateKey: 'priv' },
+    webpush: { async sendNotification() {} }
+  }));
+  const env = { DB: d1 };
+
+  const ok = await worker.fetch(
+    new Request('https://w.dev/vapid-public-key', { method: 'GET', headers: { 'X-Client-Token': 's3cret' } }),
+    env
+  );
+  assert.equal(ok.status, 200);
+  assert.equal((await ok.json()).publicKey, 'pub');
+
+  const wrong = await worker.fetch(
+    new Request('https://w.dev/vapid-public-key', { method: 'GET', headers: { 'X-Client-Token': 'nope' } }),
+    env
+  );
+  assert.equal(wrong.status, 401);
+
+  const missing = await worker.fetch(new Request('https://w.dev/vapid-public-key', { method: 'GET' }), env);
+  assert.equal(missing.status, 401);
+});
+
+test('CORS: OPTIONS /vapid-public-key preflight answered, GET echoes the allowed origin', async () => {
+  const d1 = createTestD1();
+  const worker = createSingleUserCloudflareWorker((env) => ({
+    db: createD1Adapter(env.DB),
+    masterKey: MASTER_KEY,
+    vapid: { email: 'mailto:x@example.com', publicKey: 'pub', privateKey: 'priv' },
+    webpush: { async sendNotification() {} },
+    cors: { origin: 'https://app.example.com' }
+  }));
+  const env = { DB: d1 };
+
+  const preflight = await worker.fetch(
+    new Request('https://w.dev/vapid-public-key', { method: 'OPTIONS', headers: { Origin: 'https://app.example.com' } }),
+    env
+  );
+  assert.equal(preflight.status, 204);
+  assert.equal(preflight.headers.get('Access-Control-Allow-Origin'), 'https://app.example.com');
+  assert.match(preflight.headers.get('Access-Control-Allow-Headers'), /X-Client-Token/);
+
+  const got = await worker.fetch(
+    new Request('https://w.dev/vapid-public-key', { method: 'GET', headers: { Origin: 'https://app.example.com' } }),
+    env
+  );
+  assert.equal(got.status, 200);
+  assert.equal(got.headers.get('Access-Control-Allow-Origin'), 'https://app.example.com');
+});