CORS Error: 'Access-Control-Allow-Origin' Header Missing - How to Fix

This article explains how to resolve the common CORS error 'No 'Access-Control-Allow-Origin' header is present on the requested resource.'

For Developers:

The error occurs when a website or application tries to make a request from a different origin (domain, protocol, or port) than the one it was served from. To fix this, you need to add the 'Access-Control-Allow-Origin' header to your server response. This header tells the browser that it is safe to allow cross-origin requests from a specific origin.

Here's an example of adding the header in Node.js:

res.setHeader('Access-Control-Allow-Origin', 'https://example.com');

This code allows requests from 'https://example.com' to access your server's resources.

For Non-Developers:

If you're not a developer, you can try the following:

• Contact the website or API owner: Request them to add the necessary headers to their server response.
• Use a proxy server: A proxy server can add the required headers to your requests. However, this is not always a reliable solution and may not work in all cases.

By understanding the cause and applying the right solution, you can overcome this CORS error and enable successful cross-origin requests.