diff --git a/.eslintrc.yaml b/.eslintrc.yaml
index 11a242c8..03ccdd0f 100644
--- a/.eslintrc.yaml
+++ b/.eslintrc.yaml
@@ -1,6 +1,8 @@
 root: true
 extends:
   - airbnb-typescript/base
+env:
+  jquery: true
 globals:
   Atomics: readonly
   SharedArrayBuffer: readonly
diff --git a/packages/hydrooj/package.json b/packages/hydrooj/package.json
index 2f00a67f..ebd028f1 100644
--- a/packages/hydrooj/package.json
+++ b/packages/hydrooj/package.json
@@ -1,6 +1,6 @@
 {
     "name": "hydrooj",
-    "version": "2.20.49",
+    "version": "2.20.50",
     "bin": "bin/hydrooj.js",
     "main": "dist/loader.js",
     "typings": "dist/loader.d.ts",
diff --git a/packages/hydrooj/src/handler/user.ts b/packages/hydrooj/src/handler/user.ts
index 8b85615d..8d202817 100644
--- a/packages/hydrooj/src/handler/user.ts
+++ b/packages/hydrooj/src/handler/user.ts
@@ -57,7 +57,7 @@ class UserLogoutHandler extends Handler {
     }
 }
 
-class UserRegisterHandler extends Handler {
+export class UserRegisterHandler extends Handler {
     async get() {
         this.response.template = 'user_register.html';
     }
diff --git a/packages/hydrooj/src/model/builtin.ts b/packages/hydrooj/src/model/builtin.ts
index 51523b7d..616ce61b 100644
--- a/packages/hydrooj/src/model/builtin.ts
+++ b/packages/hydrooj/src/model/builtin.ts
@@ -231,7 +231,7 @@ export const PRIV = {
     PRIV_REJUDGE: 1 << 13,
     PRIV_VIEW_USER_SECRET: 1 << 14,
     PRIV_VIEW_JUDGE_STATISTICS: 1 << 15,
-    PRIV_UNLIMITED_RATE: 1 << 22,
+    PRIV_UNLIMITED_ACCESS: 1 << 22,
 
     PRIV_ALL: -1,
     PRIV_DEFAULT: 0,
diff --git a/packages/hydrooj/src/service/bus.ts b/packages/hydrooj/src/service/bus.ts
index ce7408a6..c5f28f3f 100644
--- a/packages/hydrooj/src/service/bus.ts
+++ b/packages/hydrooj/src/service/bus.ts
@@ -12,6 +12,7 @@ import type {
 import type { DomainDoc } from '../loader';
 import type { DocType } from '../model/document';
 import type { ProblemSolutionHandler } from '../handler/problem';
+import type { UserRegisterHandler } from '../handler/user';
 
 const _hooks: Record<keyof any, Array<(...args: any[]) => any>> = {};
 const logger = new Logger('bus', true);
@@ -23,7 +24,7 @@ function isBailed(value: any) {
 export type Disposable = () => void;
 export type VoidReturn = Promise<any> | any;
 
-export interface EventMap {
+export interface EventMap extends Record<string, any> {
     'app/started': () => void
     'app/load/lib': () => VoidReturn
     'app/load/locale': () => VoidReturn
@@ -63,6 +64,10 @@ export interface EventMap {
 
     'handler/create': (thisArg: Handler) => VoidReturn
     'handler/init': (thisArg: Handler) => VoidReturn
+    'handler/before-prepare/UserRegister': (thisArg: UserRegisterHandler) => VoidReturn
+    'handler/before/UserRegister': (thisArg: UserRegisterHandler) => VoidReturn
+    'handler/after/UserRegister': (thisArg: UserRegisterHandler) => VoidReturn
+    'handler/finish/UserRegister': (thisArg: UserRegisterHandler) => VoidReturn
     'handler/solution/get': (thisArg: ProblemSolutionHandler) => VoidReturn
 
     'discussion/before-add': (
diff --git a/packages/hydrooj/src/service/server.ts b/packages/hydrooj/src/service/server.ts
index 4227f441..9a6e7025 100644
--- a/packages/hydrooj/src/service/server.ts
+++ b/packages/hydrooj/src/service/server.ts
@@ -274,7 +274,7 @@ export class HandlerCommon {
     extraTitleContent?: string;
 
     async limitRate(op: string, periodSecs: number, maxOperations: number) {
-        if (this.user && this.user.hasPriv(PRIV.PRIV_UNLIMITED_RATE)) return;
+        if (this.user && this.user.hasPriv(PRIV.PRIV_UNLIMITED_ACCESS)) return;
         await opcount.inc(op, this.request.ip, periodSecs, maxOperations);
     }
 
@@ -352,6 +352,7 @@ export class Handler extends HandlerCommon {
     ctx: Koa.Context;
 
     request: {
+        method: string,
         host: string,
         hostname: string,
         ip: string,
@@ -384,6 +385,7 @@ export class Handler extends HandlerCommon {
         super();
         this.ctx = ctx;
         this.request = {
+            method: ctx.request.method.toLowerCase(),
             host: ctx.request.host,
             hostname: ctx.request.hostname,
             ip: ctx.request.ip,
@@ -634,15 +636,16 @@ async function handle(ctx, HandlerClass, checker) {
         }
 
         await bus.serial('handler/init', h);
-
+        await bus.serial(`handler/before-prepare/${HandlerClass.name.replace(/Handler$/, '')}`, h);
         if (h._prepare) await h._prepare(args);
         if (h.prepare) await h.prepare(args);
-
+        await bus.serial(`handler/before/${HandlerClass.name.replace(/Handler$/, '')}`, h);
         if (h[method]) await h[method](args);
         if (operation) await h[`post${operation}`](args);
-
+        await bus.serial(`handler/after/${HandlerClass.name.replace(/Handler$/, '')}`, h);
         if (h.cleanup) await h.cleanup(args);
         if (h.finish) await h.finish(args);
+        await bus.serial(`handler/finish/${HandlerClass.name.replace(/Handler$/, '')}`, h);
     } catch (e) {
         try {
             await h.onerror(e);
diff --git a/packages/hydrooj/src/upgrade.ts b/packages/hydrooj/src/upgrade.ts
index 0e29408e..e1fbd897 100644
--- a/packages/hydrooj/src/upgrade.ts
+++ b/packages/hydrooj/src/upgrade.ts
@@ -231,6 +231,7 @@ const scripts: UpgradeScript[] = [
         const _FRESH_INSTALL_IGNORE = 1;
         await db.collection('domain.user').deleteMany({ uid: null });
         await db.collection('domain.user').deleteMany({ uid: 0 });
+        return true;
     },
     async function _15_16() {
         const _FRESH_INSTALL_IGNORE = 1;
@@ -242,6 +243,7 @@ const scripts: UpgradeScript[] = [
             if (JSON.stringify(af) !== JSON.stringify(pdoc.additional_file)) $set.additional_file = af;
             if (Object.keys($set).length) await problem.edit(pdoc.domainId, pdoc.docId, $set);
         });
+        return true;
     },
 ];
 
diff --git a/packages/recaptcha/handler.ts b/packages/recaptcha/handler.ts
new file mode 100644
index 00000000..37646067
--- /dev/null
+++ b/packages/recaptcha/handler.ts
@@ -0,0 +1,26 @@
+import superagent from 'superagent';
+import { ValidationError } from 'hydrooj/dist/error';
+import { PRIV } from 'hydrooj/dist/model/builtin';
+import * as system from 'hydrooj/dist/model/system';
+import * as bus from 'hydrooj/dist/service/bus';
+
+bus.on('handler/before/UserRegister', async (thisArg) => {
+    if (thisArg.request.method !== 'post') {
+        thisArg.UiContext.recaptchaKey = system.get('recaptcha.key');
+        return;
+    }
+    if (thisArg.user.hasPriv(PRIV.PRIV_UNLIMITED_ACCESS)) return;
+    if (!thisArg.args.captcha) throw new ValidationError('captcha');
+    const response = await superagent.post('https://recaptcha.net/recaptcha/api/siteverify')
+        .field('secret', system.get('recaptcha.secret'))
+        .field('response', thisArg.args.captcha)
+        .field('remoteip', thisArg.request.ip);
+    if (!response.body.success) throw new ValidationError('captcha fail');
+});
+
+bus.on('handler/after/UserRegister', async (thisArg) => {
+    thisArg.response.body.captcha = `\
+    <script src="https://recaptcha.net/recaptcha/api.js?render=${system.get('recaptcha.key')}"></script>
+    <input type="text" name="captcha" id="_captcha" style="display:none">
+    <input type="submit" id="_submit" style="display:none">`;
+});
diff --git a/packages/recaptcha/package.json b/packages/recaptcha/package.json
new file mode 100644
index 00000000..ac4a43f7
--- /dev/null
+++ b/packages/recaptcha/package.json
@@ -0,0 +1,12 @@
+{
+    "name": "@hydrooj/recaptcha",
+    "version": "1.0.0",
+    "description": "Google reCAPTCHA",
+    "main": "package.json",
+    "repository": "https://github.com/hydro-dev/Hydro.git",
+    "author": "undefined",
+    "license": "AGPL-3.0-only",
+    "dependencies": {
+        "superagent": "^6.1.0"
+    }
+}
\ No newline at end of file
diff --git a/packages/recaptcha/public/captcha-main.page.js b/packages/recaptcha/public/captcha-main.page.js
new file mode 100644
index 00000000..7461087a
--- /dev/null
+++ b/packages/recaptcha/public/captcha-main.page.js
@@ -0,0 +1,18 @@
+(() => {
+    const { AutoloadPage } = window.Hydro;
+
+    const page = new AutoloadPage('recaptcha', () => {
+        function captcha(event) {
+            event.preventDefault();
+            grecaptcha.ready(function () {
+                grecaptcha.execute(UiContext.recaptchaKey, { action: 'submit' }).then(function (token) {
+                    document.getElementById('_captcha').value = token;
+                    document.getElementById('_submit').click();
+                });
+            });
+        }
+        document.getElementById('submit').onclick = captcha;
+    });
+
+    window.Hydro.extraPages.push(page);
+})();
\ No newline at end of file
diff --git a/packages/recaptcha/setting.yaml b/packages/recaptcha/setting.yaml
new file mode 100644
index 00000000..ccb74570
--- /dev/null
+++ b/packages/recaptcha/setting.yaml
@@ -0,0 +1,4 @@
+key:
+  type: text
+secret:
+  type: text
\ No newline at end of file