Invalid Host Header When Ngrok Tries to Connect to React Dev Server

Have you ever encountered the “Invalid Host Header” error when using ngrok to connect to your React development server? This error can be frustrating and prevent you from accessing your application through ngrok. But don’t worry, in this blog post, we will explore different solutions to resolve this issue.

Solution 1: Specify the Host Header

One way to fix the “Invalid Host Header” error is by specifying the host header in your React development server configuration. To do this, open your package.json file and add the following line:

"scripts": {
  "start": "react-scripts start --host your-ngrok-subdomain.ngrok.io"
}

Replace your-ngrok-subdomain with your actual ngrok subdomain. This will set the host header to your ngrok subdomain and allow ngrok to connect to your React development server.

Solution 2: Use a Proxy

If the first solution didn’t work for you, another approach is to use a proxy. You can configure your React development server to proxy requests to ngrok. Here’s how:

First, install the http-proxy-middleware package by running the following command:

npm install http-proxy-middleware --save-dev

Next, create a new file called setupProxy.js in the root of your React project and add the following code:

const { createProxyMiddleware } = require('http-proxy-middleware');

module.exports = function(app) {
  app.use(
    '/api',
    createProxyMiddleware({
      target: 'http://your-ngrok-subdomain.ngrok.io',
      changeOrigin: true,
    })
  );
};

Make sure to replace your-ngrok-subdomain with your actual ngrok subdomain. This code sets up a proxy for requests to the /api path and redirects them to your ngrok subdomain.

Finally, start your React development server and ngrok. Your React application should now be accessible through ngrok without the “Invalid Host Header” error.

Conclusion

The “Invalid Host Header” error when ngrok tries to connect to the React development server can be resolved by either specifying the host header or using a proxy. Choose the solution that works best for your project and enjoy seamless ngrok integration with your React application.

That’s all for this blog post. We hope you found these solutions helpful. Happy coding!