API Request Tester
Test API endpoints client-side with headers, params, and body payload configurations.
100% client-side: your files never leave your browser
Headers
CORS Restrictions & Client-Side requests
This tool runs entirely in your browser. For security reasons, modern web browsers enforce CORS (Cross-Origin Resource Sharing) regulations. If the target server does not send the headers Access-Control-Allow-Origin: * (or matches ToolBundle origin), the request will fail.
How to resolve CORS blocks:
- Call API endpoints that naturally support CORS (e.g. public open APIs).
- Configure your target API server to allow CORS from our web origin.
- Install browser extensions like "Allow CORS" to disable local CORS blocks during developer testing.
- Run your local API with dev CORS permissions allowed (e.g.
cors: true).