CORS / Query String Demo

This site shows how Cross-Origin Resource Sharing (CORS) affects API requests in browsers.

Demos

• GET Demo – fetch a product list
• POST Demo – create a product

What You Can Do

• Turn CORS on/off and see how the browser reacts (preflight, blocked errors, etc.).
• Compare request/response headers with and without the query parameter.
• Experiment with successful vs. failing requests and check console errors.
• Modify the code to hit your own API and test its CORS setup.

How to Use

1. Open DevTools (F12) → Network tab.
2. Load one of the demo pages above.
3. Toggle “Enable CORS” and trigger the request (click the button / submit the form).
4. Inspect the request URL, status code, and response headers.