API Tester (REST Client)
Send HTTP requests and inspect responses. Supports all methods, custom headers, auth, and JSON body.
What is an API Tester?
An API tester lets you send HTTP requests (GET, POST, PUT, DELETE, PATCH) to any endpoint and inspect the response. It's like a lightweight Postman in your browser — set headers, add request bodies (JSON, form data, raw text), and view response status, headers, timing, and body. Everything runs client-side via the Fetch API.
Common Use Cases
- •Testing REST API endpoints during development
- •Debugging API responses with different headers and parameters
- •Verifying API authentication (Bearer tokens, API keys)
- •Comparing responses between environments
- •Quick API exploration without installing Postman or curl
Frequently Asked Questions
Can this test APIs from any domain?
The request is made from your browser, so CORS restrictions apply. APIs that allow cross-origin requests will work. For APIs that don't, you'll need to test from a server-side tool or use a CORS proxy.
How is this different from Postman?
This is a lightweight, browser-based alternative for quick API testing. It doesn't require installation or an account. For advanced features like collections, environments, pre-request scripts, and team collaboration, Postman is more suitable.