How to use API Tester Online
- Start by entering the URL and any method, headers or body in API Tester Online.
- Press the button and API Tester Online sends the request from your browser.
- Review the result, which API Tester Online fetches live from the API you entered.
About this tool
API Tester Online runs in your browser with no backend of its own. API Tester Online sends HTTP requests from your browser to the API endpoint you enter and shows the status, headers and body of the response.
It is a thin client around the browser fetch API — no proxy and no stored credentials, just the request you configure. The request is sent from your browser straight to the API you name; this site has no backend and never receives it, though that server and your network can see it. Cross-origin calls follow the browser's CORS rules, and a connection is required.
Frequently asked questions
What is API Tester Online for?
API Tester Online sends the HTTP request you configure from your browser to the API you specify and shows the response status, headers and body.
Is API Tester Online free to use?
Yes — API Tester Online is completely free, with no usage limits.
Does API Tester Online send my request anywhere?
Yes — API Tester Online sends the request from your browser directly to the URL you enter. This site has no backend and never receives it, but the target server and your network do, and cross-origin calls follow browser CORS rules.
Can API Tester Online call any API from the browser?
API Tester Online can call any endpoint your browser is allowed to reach, but cross-origin APIs must send permissive CORS headers or the browser will block the response — that is a browser rule, not a limit of API Tester Online.