What is an HTTP client?

An HTTP client sends requests to a web server or API and shows what comes back. Developers use one to try an endpoint before writing code against it, check that an API returns the right status and data, reproduce a bug, or see which headers a server sends. Desktop apps such as Postman, Insomnia and Yaak, and the curl command-line tool, are the best-known examples.

Tool description

This tool is a lightweight HTTP client that runs in your browser, with nothing to install. Pick a method, enter a URL, add query parameters, headers, a body and credentials, and press Send. The response shows its status code, time, size, headers and body, with JSON formatted for reading. You can also paste a curl command to fill in the whole request, or copy any request as a curl command.

Features

  • GET, POST, PUT, PATCH, DELETE, HEAD and OPTIONS requests
  • Query parameters kept in sync with the URL, so you can edit either one
  • Custom headers, with a warning for the ones browsers won't send
  • JSON, XML, plain text and URL-encoded form bodies, with the Content-Type set for you
  • Bearer token and basic authentication
  • Response status, time, size, headers and body, with JSON pretty-printed
  • Image responses shown as a preview, and any response downloadable as a file
  • Import a request by pasting a curl command, including Copy as cURL from browser developer tools
  • Export the current request as a curl command

How it works

The tool sends your request with the browser's own fetch API, straight from your device to the server, so nothing passes through our servers. The browser's security rules apply, though. A request to another website only gets a readable response when that server allows it through CORS (Cross-Origin Resource Sharing), which most public APIs do and many private ones don't. The browser also refuses to let a web page set some headers, such as Cookie, Host, Origin and User-Agent, and only shows the response headers the server chooses to expose. Pages served over https:// can't call plain http:// addresses, except localhost in most browsers.

Tips

  • If a request fails with no response, open your browser's developer console: it names the reason, which is usually a missing Access-Control-Allow-Origin header on the server.
  • To test your own API, allow this site's origin in its CORS settings, or test it on localhost.
  • A request that needs cookies or an IP address that only a server has is better sent with curl. Copy it from the cURL tab and run it in a terminal.
  • Press Enter in the URL field to send the request.
  • Leave out the scheme and the tool adds https://, or http:// for localhost and 127.0.0.1.
  • For an API key, add it as a header, such as X-Api-Key, in the Headers tab.