diff --git a/src/backend/controllers/auth/AuthController.js b/src/backend/controllers/auth/AuthController.js
index 0568cd511..bff21250a 100644
--- a/src/backend/controllers/auth/AuthController.js
+++ b/src/backend/controllers/auth/AuthController.js
@@ -404,6 +404,7 @@ export class AuthController extends PuterController {
                     no_temp_user: false,
                     requires_email_confirmation: false,
                     message: null,
+                    code: null,
                 };
                 try {
                     await this.clients.event?.emitAndWait(
@@ -418,6 +419,11 @@ export class AuthController extends PuterController {
                     throw new HttpError(
                         403,
                         validateEvent.message ?? 'Signup blocked',
+                        {
+                            ...(validateEvent.code
+                                ? { code: validateEvent.code }
+                                : {}),
+                        },
                     );
                 }
                 if (is_temp && validateEvent.no_temp_user) {
@@ -425,7 +431,12 @@ export class AuthController extends PuterController {
                         403,
                         validateEvent.message ??
                             'Temporary accounts are disabled',
-                        { legacyCode: 'must_login_or_signup' },
+                        {
+                            legacyCode: 'must_login_or_signup',
+                            ...(validateEvent.code
+                                ? { code: validateEvent.code }
+                                : {}),
+                        },
                     );
                 }
                 const force_email_confirmation = Boolean(
diff --git a/src/backend/controllers/auth/AuthController.test.ts b/src/backend/controllers/auth/AuthController.test.ts
new file mode 100644
index 000000000..9eed45f2b
--- /dev/null
+++ b/src/backend/controllers/auth/AuthController.test.ts
@@ -0,0 +1,114 @@
+/**
+ * Copyright (C) 2024-present Puter Technologies Inc.
+ *
+ * This file is part of Puter.
+ *
+ * Puter is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import { afterAll, beforeAll, describe, expect, it } from 'vitest';
+import { PuterServer } from '../../server.js';
+import { setupTestServer } from '../../testUtil.js';
+import type { EventClient } from '../../clients/EventClient.js';
+import { HttpError } from '../../core/http/HttpError.js';
+
+let server: PuterServer;
+let eventClient: EventClient;
+
+beforeAll(async () => {
+    server = await setupTestServer();
+    eventClient = server.clients.event as unknown as EventClient;
+});
+
+afterAll(async () => {
+    await server?.shutdown();
+});
+
+describe('puter.signup.validate event', () => {
+    it('supports code in the validate event when allow is false', async () => {
+        eventClient.on('puter.signup.validate', (_key, data) => {
+            const event = data as {
+                allow: boolean;
+                message: string | null;
+                code: string | null;
+            };
+            event.allow = false;
+            event.message = 'Region not supported';
+            event.code = 'region_blocked';
+        });
+
+        const validateEvent = {
+            req: {},
+            data: {},
+            ip: '127.0.0.1',
+            email: 'test@example.com',
+            allow: true,
+            no_temp_user: false,
+            requires_email_confirmation: false,
+            message: null as string | null,
+            code: null as string | null,
+        };
+
+        await eventClient.emitAndWait(
+            'puter.signup.validate',
+            validateEvent,
+            {},
+        );
+
+        expect(validateEvent.allow).toBe(false);
+        expect(validateEvent.message).toBe('Region not supported');
+        expect(validateEvent.code).toBe('region_blocked');
+
+        // Verify the HttpError constructed from this event carries the code
+        const err = new HttpError(
+            403,
+            validateEvent.message ?? 'Signup blocked',
+            {
+                ...(validateEvent.code
+                    ? { code: validateEvent.code }
+                    : {}),
+            },
+        );
+        expect(err.statusCode).toBe(403);
+        expect(err.message).toBe('Region not supported');
+        expect(err.code).toBe('region_blocked');
+    });
+
+    it('omits code from HttpError when extension does not set it', async () => {
+        const validateEvent = {
+            req: {},
+            data: {},
+            ip: '127.0.0.1',
+            email: 'nocode@example.com',
+            allow: false,
+            no_temp_user: false,
+            requires_email_confirmation: false,
+            message: 'Blocked',
+            code: null as string | null,
+        };
+
+        const err = new HttpError(
+            403,
+            validateEvent.message ?? 'Signup blocked',
+            {
+                ...(validateEvent.code
+                    ? { code: validateEvent.code }
+                    : {}),
+            },
+        );
+        expect(err.statusCode).toBe(403);
+        expect(err.message).toBe('Blocked');
+        expect(err.code).toBeUndefined();
+    });
+});
diff --git a/src/backend/services/auth/OIDCService.ts b/src/backend/services/auth/OIDCService.ts
index 068caa894..9350b2a0c 100644
--- a/src/backend/services/auth/OIDCService.ts
+++ b/src/backend/services/auth/OIDCService.ts
@@ -407,6 +407,7 @@ export class OIDCService extends PuterService {
             no_temp_user: false,
             requires_email_confirmation: false,
             message: null as string | null,
+            code: null as string | null,
         };
         try {
             await this.clients.event?.emitAndWait(
@@ -421,6 +422,7 @@ export class OIDCService extends PuterService {
             return {
                 success: false,
                 error: validateEvent.message ?? 'Signup blocked',
+                ...(validateEvent.code ? { code: validateEvent.code } : {}),
             };
         }