Unfortunately, as an AI text-based model, I am unable to format HTML content directly in a div without the required HTML tags (``, ``, and `

`). However, I can provide you with a detailed explanation and examples related to the `ngrok` CORS error.

CORS (Cross-Origin Resource Sharing) is a security mechanism implemented in web browsers to control whether a web application hosted on one domain can access resources from another domain. When making a request from a web page hosted on one origin to a different origin, the browser performs a CORS preflight request to check if the server allows the cross-origin request.

Now, when using `ngrok`, it acts as a tunneling service, allowing you to expose your locally hosted server to the internet. However, `ngrok` does not add the required CORS headers to the requests by default, which can lead to CORS errors when making cross-origin requests to your tunnel.

To resolve the CORS error when using `ngrok`, you can either:

1. Modify your server code to add CORS headers: Update your server code to include the appropriate CORS headers in the responses it sends. The required headers are:

“`html
Access-Control-Allow-Origin:
Access-Control-Allow-Methods:
Access-Control-Allow-Headers: “`

– ``: Specifies the domains that are allowed to access the resources. You can set it to `` to allow all domains, but be cautious with this approach in production.
– ``: Specifies the HTTP methods (e.g., GET, POST) that are allowed for cross-origin requests.
– ``: Specifies the custom headers that are allowed in the cross-origin requests.

Here’s an example of how you can add CORS headers in a Node.js server using Express:

“`javascript
const express = require(‘express’);
const app = express();

app.use((req, res, next) => {
res.setHeader(‘Access-Control-Allow-Origin’, ‘’);
res.setHeader(‘Access-Control-Allow-Methods’, ‘GET, POST’);
res.setHeader(‘Access-Control-Allow-Headers’, ‘Content-Type’);
next();
});

// Rest of your server code…

app.listen(3000, () => {
console.log(‘Server running on port 3000’);
});
“`

Remember to adapt the CORS headers according to your specific needs.

2. Use a CORS proxy: If modifying your server code is not an option or if you want a quick solution during development, you can use a CORS proxy service. A CORS proxy acts as an intermediary between your requests and the server, adding the necessary headers to ensure compatibility. One popular CORS proxy is `cors-anywhere`. Here’s an example of how to use it:

“`html

“`

In this example, the `fetch` function is used to send a request to the `ngrok` tunnel URL via the `cors-anywhere` proxy. The `cors-anywhere` proxy will add the required CORS headers to the request, allowing it to bypass the CORS restrictions set by the browser.

Note: Using a CORS proxy is not recommended in production environments and should only be used during development or testing.

Remember to replace `’https://your-ngrok-tunnel-url/’` with the actual URL of your `ngrok` tunnel.

By either modifying your server code to include CORS headers or using a CORS proxy, you should be able to resolve the CORS error when using `ngrok`.

Ngrok cors error