How it works
How to use the API Tester
Build the request
Choose the HTTP method, enter the URL and add headers (one per line) and a body.
Send it
The request goes straight from your browser to the API — no proxy in between.
Inspect the response
See the status code, time, size, headers and a pretty-printed body.
About the API Tester
Send GET, POST, PUT, PATCH and DELETE requests with custom headers and a JSON body, then inspect the status, timing, size, headers and pretty-printed response. Requests go directly from your browser, so the API must allow CORS.
Built for developers
Why developers use it
Private by design
Runs 100% in your browser. Nothing you paste is uploaded, logged or stored on a server.
Instant results
Output updates as you type, with precise error locations when something is wrong.
Works offline
Once loaded, the tool keeps working without a connection. Install it as an app if you like.
Free, no sign-up
No accounts, no limits, no watermarks.
FAQ
Frequently asked questions
Why do some requests fail with a CORS error?
Browsers only let a page read a response when the server sends Access-Control-Allow-Origin. Public APIs usually do; private ones often don’t. For those, use the curl converters to generate code you can run on a server.
Is my data uploaded anywhere?
No. Everything runs locally in your browser — nothing you type, paste or open is sent to a server, logged or stored. The tool keeps working offline once the page has loaded.
Keep going
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