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API Request Tester

Send HTTP requests straight from your browser and inspect the response. Paste a cURL command to fill everything in, or build the request yourself. Works with public APIs and with your own app on localhost, as long as it allows cross-origin (CORS) requests.

Response

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Press Send to make a request.

Why did my request fail with a network error?

Almost always it's CORS. Browsers block a page from reading responses from another domain unless that server sends an Access-Control-Allow-Origin header. Public APIs built for browsers allow it, but many internal and server-to-server APIs don't. For those, use Copy as cURL and run the request from your terminal.

Import a cURL command

Click Import cURL (or just paste a command into the address box) and the method, address, headers, body and login are filled in for you. It understands commands written for bash, Windows cmd and PowerShell, including the ones from your browser's developer tools (Network tab → right-click a request → Copy as cURL), and options such as -X, -H, -d/--data-raw, --json, --data-urlencode, -G, -u, -b and -F. Anything that can't be carried over, such as file uploads or headers that browsers don't allow pages to set (Cookie, User-Agent), is listed so nothing is silently lost.

Testing an API on localhost

You can call your own app while you develop it, for example http://localhost:3000/api/users. Two things to know: your app has to allow requests from this page (CORS), and some browsers ask once for permission to reach devices on your local network; click Allow. If a request fails, the tool checks whether your server is running at all or only needs CORS turned on, and shows how to enable it in common frameworks (Express, FastAPI, Spring Boot, Django, ASP.NET).

Where do requests go?

Requests go straight from your browser to the URL you enter. They don't pass through any DevToolbox server, so we never see your tokens or data.

Free APIs to practise with