API Tester (REST Client)
A free, Postman-style REST API client that runs entirely in your browser. Choose the HTTP method, add query params, headers and authentication (Bearer or Basic), send a JSON, form or raw body, then inspect the status, timing, size, response headers and pretty-printed body. Because it runs in the browser it can call any API that allows cross-origin (CORS) requests — your tokens and data never leave your machine.
Free · No sign-up · Updated August 2026
Sends real HTTP requests from your browser, so it can only reach APIs that allow cross-origin (CORS) requests — public APIs and your own APIs with CORS enabled. Nothing is proxied; your tokens and data stay in your browser.
🔒 This tool runs entirely in your browser. Your data is never uploaded.
Frequently asked questions
Is this a Postman alternative?＋
For quick REST testing in the browser, yes — set the method, params, headers, auth and body and inspect the response. The main difference is CORS (see below).
Why do some requests fail with a CORS error?＋
Because it runs in your browser, it can only call APIs that send cross-origin (CORS) headers — public APIs and your own APIs with CORS enabled. Postman's desktop app avoids this because it isn't a browser and makes requests from its own process.
Are my tokens and data safe?＋
Yes — requests go directly from your browser to the API. Nothing is proxied through our servers, so your URLs, tokens and responses never leave your machine.
Which methods and body types are supported?＋
GET, POST, PUT, PATCH, DELETE, HEAD and OPTIONS, with JSON, raw text, x-www-form-urlencoded and form-data bodies, plus Bearer and Basic auth.