feat(nextjs): point invalid-key errors at the Clerk CLI

.changeset/nextjs-cli-key-errors.md

@@ -0,0 +1,5 @@
+---
+'@clerk/nextjs': patch
+---
+
+`clerkMiddleware()` now points key misconfiguration at the Clerk CLI: missing keys outside development throw a deploy-oriented error recommending `npx clerk@latest deploy` (`code=missing_env_keys_production`), and the publishable key format is validated upfront, throwing `npx clerk@latest init` guidance in development or `npx clerk@latest env pull --instance prod` guidance in production (`code=invalid_env_keys`, `code=invalid_env_keys_production`) instead of failing later with `Publishable key not valid.`

packages/nextjs/src/server/__tests__/clerkMiddleware.test.ts

@@ -266,7 +266,7 @@ describe('clerkMiddleware(params)', () => {
   it('propagates middleware dynamic keys to the next request', async () => {
     const options = {
       secretKey: 'sk_test_xxxxxxxxxxxxxxxxxx',
-      publishableKey: 'pk_test_xxxxxxxxxxxxx',
+      publishableKey: 'pk_test_ZHluYW1pYy1rZXlzLmNsZXJrLmFjY291bnRzLmRldiQ',
       signInUrl: '/foo',
       signUpUrl: '/bar',
     };
@@ -286,7 +286,7 @@ describe('clerkMiddleware(params)', () => {
     it('with synchronous callback', async () => {
       const options = {
         secretKey: 'sk_test_xxxxxxxxxxxxxxxxxx',
-        publishableKey: 'pk_test_xxxxxxxxxxxxx',
+        publishableKey: 'pk_test_ZHluYW1pYy1rZXlzLmNsZXJrLmFjY291bnRzLmRldiQ',
         signInUrl: '/foo',
         signUpUrl: '/bar',
       };
@@ -313,7 +313,7 @@ describe('clerkMiddleware(params)', () => {
     it('with asynchronous callback', async () => {
       const options = {
         secretKey: 'sk_test_xxxxxxxxxxxxxxxxxx',
-        publishableKey: 'pk_test_xxxxxxxxxxxxx',
+        publishableKey: 'pk_test_ZHluYW1pYy1rZXlzLmNsZXJrLmFjY291bnRzLmRldiQ',
         signInUrl: '/foo',
         signUpUrl: '/bar',
       };

packages/nextjs/src/server/__tests__/clerkMiddlewareInvalidKeys.test.ts

@@ -0,0 +1,59 @@
+import { automatedEnvironmentVariables } from '@clerk/shared/utils';
+import type { NextFetchEvent } from 'next/server';
+import { NextRequest } from 'next/server';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+
+// The mock SHOULD exist before the imports: keys are present but not parseable as Clerk keys, so
+// the invalid-key error path is reachable.
+vi.mock(import('../constants.js'), async importOriginal => {
+  const actual = await importOriginal();
+  return {
+    ...actual,
+    PUBLISHABLE_KEY: 'pk_test_placeholder',
+    SECRET_KEY: 'sk_test_placeholder',
+  };
+});
+
+describe('clerkMiddleware when Clerk env vars are invalid', () => {
+  beforeEach(() => {
+    vi.stubEnv('NODE_ENV', 'development');
+    automatedEnvironmentVariables.forEach(name => {
+      vi.stubEnv(name, undefined);
+      vi.stubGlobal(name, undefined);
+    });
+    vi.resetModules();
+  });
+
+  afterEach(() => {
+    vi.unstubAllEnvs();
+    vi.unstubAllGlobals();
+    vi.resetModules();
+  });
+
+  const runMiddleware = async () => {
+    const { clerkMiddleware } = await import('../clerkMiddleware.js');
+    const request = new NextRequest('https://example.com/protected');
+    return clerkMiddleware()(request, {} as NextFetchEvent);
+  };
+
+  it('throws the invalid-key error pointing at the CLI', async () => {
+    await expect(runMiddleware()).rejects.toThrow(/npx clerk@latest init/);
+    await expect(runMiddleware()).rejects.toThrow(/\(code=invalid_env_keys\)/);
+  });
+
+  it('throws the production invalid-key error pointing at env pull', async () => {
+    vi.stubEnv('NODE_ENV', 'production');
+    await expect(runMiddleware()).rejects.toThrow(/npx clerk@latest env pull --instance prod/);
+    await expect(runMiddleware()).rejects.toThrow(/\(code=invalid_env_keys_production\)/);
+  });
+
+  it('names the env var and the expected key format in the message', async () => {
+    const { invalidEnvKeys, productionInvalidEnvKeys } = await import('../errors.js');
+    for (const message of [invalidEnvKeys, productionInvalidEnvKeys]) {
+      expect(message).toContain('NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY');
+      expect(message).toContain('pk_test_');
+    }
+    expect(invalidEnvKeys).toContain('npx clerk@latest init');
+    expect(productionInvalidEnvKeys).toContain('npx clerk@latest env pull --instance prod');
+  });
+});

packages/nextjs/src/server/clerkMiddleware.ts

@@ -24,6 +24,7 @@ import {
 import { clerkFrontendApiProxy, DEFAULT_PROXY_PATH, matchProxyPath } from '@clerk/backend/proxy';
 import { isProductionFromPublishableKey, parsePublishableKey } from '@clerk/shared/keys';
 import { handleNetlifyCacheInDevInstance } from '@clerk/shared/netlifyCacheHandler';
+import { isDevelopmentEnvironment } from '@clerk/shared/utils';
 import { isMalformedURLError } from '@clerk/shared/pathMatcher';
 import { isAutoProxyDisabledFromEnvironment, shouldAutoProxy } from '@clerk/shared/proxy';
 import { notFound as nextjsNotFound } from 'next/navigation';
@@ -41,6 +42,7 @@ import { DOMAIN, PROXY_URL, PUBLISHABLE_KEY, SECRET_KEY, SIGN_IN_URL, SIGN_UP_UR
 import { type ContentSecurityPolicyOptions, createContentSecurityPolicyHeaders } from './content-security-policy';
 import { errorThrower } from './errorThrower';
 import { getHeader } from './headers-utils';
+import { invalidEnvKeys, productionInvalidEnvKeys, productionMissingEnvVars } from './errors';
 import { getKeylessCookieValue } from './keyless';
 import { clerkMiddlewareRequestDataStorage, clerkMiddlewareRequestDataStore } from './middleware-storage';
 import {
@@ -155,12 +157,24 @@ export const clerkMiddleware = ((...args: unknown[]): NextMiddleware | NextMiddl
 
       const publishableKey = assertKey(
         resolvedParams.publishableKey || PUBLISHABLE_KEY || keyless?.publishableKey,
-        () => errorThrower.throwMissingPublishableKeyError(),
+        () => {
+          if (isDevelopmentEnvironment()) {
+            return errorThrower.throwMissingPublishableKeyError();
+          }
+          throw new Error(productionMissingEnvVars);
+        },
       );
 
-      const secretKey = assertKey(resolvedParams.secretKey || SECRET_KEY || keyless?.secretKey, () =>
-        errorThrower.throwMissingSecretKeyError(),
-      );
+      const secretKey = assertKey(resolvedParams.secretKey || SECRET_KEY || keyless?.secretKey, () => {
+        if (isDevelopmentEnvironment()) {
+          return errorThrower.throwMissingSecretKeyError();
+        }
+        throw new Error(productionMissingEnvVars);
+      });
+
+      if (!parsePublishableKey(publishableKey)) {
+        throw new Error(isDevelopmentEnvironment() ? invalidEnvKeys : productionInvalidEnvKeys);
+      }
 
       // Handle Frontend API proxy requests early, before authentication
       const requestUrl = new URL(request.nextUrl.href);

packages/nextjs/src/server/errors.ts

@@ -34,6 +34,30 @@ For more details, see https://clerk.com/err/auth-middleware
 `;
 };
 
+export const productionMissingEnvVars = `Clerk: Missing environment variables (NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY and CLERK_SECRET_KEY).
+
+To deploy this application to production, run:
+
+  npx clerk@latest deploy
+
+This provisions a production Clerk instance and walks you through DNS and OAuth setup. If you already have a production instance, run \`npx clerk@latest env pull --instance prod\` to write its keys to your env file, and set the same keys in your deployment environment. (code=missing_env_keys_production)`;
+
+export const invalidEnvKeys = `Clerk: Invalid environment keys. NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY is set but is not a valid Clerk publishable key (expected format: pk_test_... or pk_live_...).
+
+To set up Clerk for this project with valid keys, run:
+
+  npx clerk@latest init
+
+The command is non-interactive and requires no Clerk account or login: it provisions temporary development keys automatically and writes them to your .env.local file. Then restart your dev server. Do not invent placeholder keys - they will fail. If you already have a Clerk application, copy its keys from https://dashboard.clerk.com into .env.local instead. (code=invalid_env_keys)`;
+
+export const productionInvalidEnvKeys = `Clerk: Invalid environment keys. NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY is set but is not a valid Clerk publishable key (expected format: pk_test_... or pk_live_...).
+
+To write the keys of an existing Clerk instance to your env file, run:
+
+  npx clerk@latest env pull --instance prod
+
+Set the same keys in your deployment environment. If you do not have a production Clerk instance yet, run \`npx clerk@latest deploy\` to provision one. (code=invalid_env_keys_production)`;
+
 export const authSignatureInvalid = `Clerk: Unable to verify request, this usually means the Clerk middleware did not run. Ensure Clerk's middleware is properly integrated and matches the current route. For more information, see: https://clerk.com/docs/reference/nextjs/clerk-middleware. (code=auth_signature_invalid)`;
 
 export const encryptionKeyInvalid = `Clerk: Unable to decrypt request data, this usually means the encryption key is invalid. Ensure the encryption key is properly set. For more information, see: https://clerk.com/docs/reference/nextjs/clerk-middleware#dynamic-keys. (code=encryption_key_invalid)`;