API Tester
Send HTTP requests to any REST API and inspect the response — works with public endpoints and your localhost dev server.
Query parameters are appended to the URL.
Headers sent with the request. Content-Type defaults to application/json when a JSON body is present.
Sent with POST, PUT and PATCH. JSON, plain text or any raw payload.
Enter a URL above, then press ⌘/Ctrl + Enter to send the request.
An API tester (REST client) lets you send an HTTP request to a web API and see exactly what comes back — no code required. Pick a method, type the endpoint URL, and add query params, headers, a body or auth as needed, then press Send (or ⌘/Ctrl + Enter). You get the status code, how long it took, the size, the response headers and a pretty-printed body. The request goes straight from your browser to the API you name — nothing passes through LK Forge — so it works with public endpoints and your localhost dev server. Because the browser enforces CORS, the target server must allow cross-origin requests for the body to be readable; most public and local dev APIs do.
Frequently Asked Questions
What is an API tester?
An API tester, also called a REST client, lets you send an HTTP request to a web API and see exactly what comes back without writing any code. You choose a method such as GET or POST, type the endpoint URL, optionally add query parameters, headers, a request body and authentication, then send it and inspect the response — its status code, how long it took, its headers and its body. It is the quickest way to check that an endpoint behaves as expected, to explore a third-party API, or to debug your own backend while you build it. This tester runs entirely in your browser.
Which HTTP methods are supported?
This API tester supports all of the common HTTP methods: GET to read a resource, POST to create one, PUT and PATCH to update, DELETE to remove, HEAD to fetch only the response headers, and OPTIONS to ask what a server allows. Pick the method from the dropdown next to the URL. A request body is sent only with POST, PUT and PATCH, which is how those methods normally carry data; GET, HEAD, DELETE and OPTIONS are sent without a body, matching how servers expect them.
Can I test a localhost API or a public API?
Yes — the API tester can call both a localhost endpoint and a public API. Because the request is sent from your browser, you can point it at your local development server — for example http://localhost:3000/api — and at public APIs on the internet. One thing to know: the browser enforces CORS, so a server has to include the right cross-origin headers for the browser to let your page read the response. Most public APIs and most local dev servers do, but if you get a CORS or network error, that is the target server not allowing the request, not a fault in the tool.
Is my request data private?
Yes — your request data stays private. The request is sent directly from your browser to the API you name — it does not pass through LK Forge, and nothing you type (URLs, headers, tokens or bodies) is uploaded to us, logged or stored. There is no account and no sign-up. Treat the API keys and tokens you paste as you would anywhere: they go only to the endpoint you are calling. The Copy as cURL button builds the equivalent command-line request locally so you can reproduce the call in a terminal.