API Request Builder — Test HTTP Endpoints in Your Browser

What is an API Request Builder?

An API request builder is a tool that lets you construct and send HTTP requests without writing code or installing a desktop app. You choose a method (GET, POST, PUT, DELETE, PATCH), enter a URL, optionally add request headers and a body, and then fire the request. The response — status code, timing, headers, and body — is displayed immediately.

Why Use a Browser-Based API Tester?

Desktop tools like Postman are powerful but heavy. curl is fast but requires a terminal and remembering flag syntax. A browser-based builder gives you a clean UI with zero installation. It's perfect for quick endpoint checks, debugging webhook payloads, exploring public APIs, or sharing a reproducible request with a colleague — just copy the URL.

Key Features

• GET, POST, PUT, DELETE, and PATCH method support
• Custom request headers with key/value editor
• JSON and form-encoded request body
• Real-time response with status code and timing
• Colour-coded JSON response viewer with syntax highlighting
• Response headers tab with all returned header values
• Paste a cURL command directly into the URL field — it auto-parses
• Code snippet export in 12 languages: cURL, fetch, axios, XHR, Node.js, Python, Go, PHP, Ruby, Swift, C#, and Java
• Send response body directly to JSON Viewer for deeper inspection
• No data leaves your device — requests are sent directly from your browser

How to Use the API Request Builder

1. Select an HTTP method (GET, POST, PUT, DELETE, or PATCH)
2. Enter the full URL of the endpoint you want to test
3. Add any required headers in the Headers tab (e.g. Authorization, Content-Type)
4. For POST/PUT/PATCH, switch to the Body tab and enter your JSON payload
5. Click SEND — the response appears instantly in the right panel
6. Use the Body / Headers tabs in the response panel to inspect the result
7. Click the </> button to export the request as runnable code in any language

Paste a cURL Command and It Just Works

One of the most useful features: paste any curl command directly into the URL field and the builder automatically parses it — extracting the method, URL, headers, and body. This means you can copy a curl snippet from API documentation or a terminal and immediately have it loaded in the visual editor, ready to tweak and re-send.

Export as Code Snippets

Once you've built your request, click the </> icon next to the URL bar to open the Code Snippet panel. Choose from 12 languages and runtimes — cURL, JavaScript (fetch), JavaScript (axios), XHR, Node.js (http), Python (requests), Go, PHP, Ruby, Swift, C# (HttpClient), and Java (OkHttp). The snippet updates live as you change the method, URL, headers, or body, so you always have ready-to-paste code.

Understanding CORS Limitations

Because requests are sent from your browser rather than a server, you may encounter CORS (Cross-Origin Resource Sharing) errors when testing APIs that don't allow browser-based requests. This is a browser security restriction, not a bug in the tool. Public APIs and APIs you control will generally work fine. For restricted APIs, use the exported code snippet to run the request from a server-side environment like Node.js or Python instead.

Tips

• Set Content-Type: application/json when sending a JSON body — many APIs require it
• Use the Authorization header with Bearer <token> for protected endpoints
• Paste a cURL command directly into the command palette to jump to the API Request Builder with it preloaded
• Use the Prettify button in the response panel to auto-format minified JSON
• Forward a JSON response to the JSON Viewer using the Send To button for tree browsing
• The timing shown (e.g. 142ms) is round-trip time from your browser to the server
• cURL snippets generated by the tool include all headers and body, ready to run in a terminal