What are CORS headers?

What are CORS headers and why are they important?

CORS stands for Cross-Origin Resource Sharing. CORS headers are HTTP headers that allow servers to specify who can access their resources. They are important for web security as they prevent unauthorized access to resources from different origins.

Can you give me an example of how CORS headers work?

Sure! For instance, if a web application hosted on 'example.com' wants to request resources from 'api.example.com', the server at 'api.example.com' must include the appropriate CORS headers, like 'Access-Control-Allow-Origin: https://example.com', to allow the request.

What happens if CORS headers are not set?

If CORS headers are not set, browsers will block the request from the web application to the server, resulting in a CORS error. This is a security measure to prevent malicious sites from accessing sensitive data.

How can I enable CORS on my server?

To enable CORS, you can configure your server to include the necessary headers in the response. For example, in an Express.js application, you can use the 'cors' middleware to easily set this up.