Solving the Internal Server Error when using createUser with Clerk Authentication in NextJS App Router

Ah, the joys of authentication in NextJS! Clerk Authentication is an excellent choice for securing your NextJS app, but sometimes, it can throw a wrench in the works. Specifically, the “Internal Server Error” issue when using createUser can be frustrating. Don’t worry, friend, we’ve got you covered. In this article, we’ll dive into the solution and provide clear, step-by-step instructions to get you back on track.

What’s the issue?

The error message “Internal Server Error” is, well, less than helpful. It’s like saying, “Hey, something’s wrong, good luck figuring it out!” However, after some digging, we’ve found that the issue typically lies in one of two areas:

• Mismatched Clerk API keys: Double-check that your Clerk API keys match in both your Clerk dashboard and your NextJS app.
• Incorrect App Router configuration: Make sure your App Router is set up correctly to handle the createUser request.

Let’s get started!

Before we dive into the solution, ensure you have the following set up:

1. A Clerk account with an active subscription
2. A NextJS app with Clerk Authentication installed
3. An understanding of Clerk’s createUser functionality (if you need a refresher, check out Clerk’s documentation)

Step 1: Verify Clerk API keys

Log in to your Clerk dashboard and navigate to the ” API keys” section. Take note of your publishableKey and secretKey. Now, head over to your NextJS app and find the Clerk configuration file (usually clerk.config.js or next.config.js). Verify that the API keys match:

module.exports = {
  //...
  clerk: {
    publishableKey: 'YOUR_PUBLISHABLE_KEY',
    secretKey: 'YOUR_SECRET_KEY',
  },
};

Make sure there are no typos or incorrect values. If you’re still using an old API key, update it to the latest one from your Clerk dashboard.

Step 2: Configure App Router

The App Router is responsible for handling server-side requests in NextJS. To configure it for Clerk Authentication, create a new file called next-api/clerk/[...api].js with the following code:

import { NextApiRequest, NextApiResponse } from 'next';
import { clerk } from '../clerk.config';

export default async function handler(req: NextApiRequest, res: NextApiResponse) {
  if (req.method === 'POST') {
    try {
      const { userProfile } = req.body;
      const user = await clerk.users.createUser({
        userProfile,
      });
      return res.status(201).json(user);
    } catch (error) {
      console.error(error);
      return res.status(500).json({ message: 'Internal Server Error' });
    }
  }

  return res.status(405).json({ message: 'Method Not Allowed' });
}

This code sets up an API route to handle createUser requests. Make sure to update the clerk.config.js import path to match your actual file location.

Step 3: Implement createUser in your component

Now that the App Router is set up, let’s create a simple component to test the createUser functionality:

import { useState } from 'react';
import axios from 'axios';

const CreateUserComponent = () => {
  const [email, setEmail] = useState('');
  const [password, setPassword] = useState('');
  const [userProfile, setUserProfile] = useState({});

  const handleSubmit = async (event) => {
    event.preventDefault();
    try {
      const response = await axios.post('/api/clerk', {
        userProfile,
      });
      console.log(response.data);
    } catch (error) {
      console.error(error);
    }
  };

  return (
    <form onSubmit={handleSubmit}>
      <label>
        Email:<br>
        <input type="email" value={email} onChange={(e) => setEmail(e.target.value)} />
      </label>
      <br>
      <label>
        Password:<br>
        <input type="password" value={password} onChange={(e) => setPassword(e.target.value)} />
      </label>
      <br>
      <button type="submit">Create User</button>
    </form>
  );
};

export default CreateUserComponent;

This component uses axios to send a POST request to the App Router with the userProfile data. Update the axios.post URL to match your actual API route.

Troubleshooting tips

If you’re still encountering issues, here are some additional troubleshooting tips:

Error	Solution
API key not found	Verify that your Clerk API keys are correct and up-to-date
UserProfile data is malformed	Double-check the userProfile data being sent to Clerk. Ensure it meets the required format
Server-side error	Review your App Router configuration and Clerk setup to ensure they’re correctly integrated

Conclusion

Voilà! With these steps, you should be able to resolve the “Internal Server Error” issue when using createUser with Clerk Authentication in your NextJS App Router. Remember to double-check your Clerk API keys, App Router configuration, and userProfile data. If you’re still stuck, Clerk’s documentation and support team are excellent resources to tap into. Happy coding!

Did this article help you solve the issue? Share your experience in the comments below!

Frequently Asked Question

Got stuck with the pesky “Internal Server Error” when using `createUser` with Clerk Authentication in your NextJS App Router? Fear not, friend! We’ve got you covered with these Frequently Asked Questions.