API Tester — HTTP Request Builder
Build, send, and debug HTTP requests visually. Generate code snippets in fetch, axios, cURL, Python, Go, and Ruby. 100% browser-based.
What is an API Tester?
An API tester is a tool that lets you send HTTP requests to any URL and inspect the response. It's essential for developers who build, debug, and test REST APIs, GraphQL endpoints, and webhooks. Instead of writing code just to test an endpoint, you can visually construct requests with custom headers, authentication, query parameters, and request bodies.
Why Use an Online API Tester?
Unlike desktop tools like Postman or Insomnia, this API tester runs entirely in your browser. There's nothing to install, no account to create, and no cloud sync to worry about. Your requests and data stay local. The built-in CORS proxy lets you test APIs that would normally be blocked by browser security policies, and the code generator creates ready-to-use snippets in 6 languages so you can take your tested request straight into your codebase.
Common use cases include debugging API endpoints during development, testing authentication flows (Bearer tokens, Basic Auth, API keys), inspecting response headers and status codes, converting cURL commands from documentation into working code, and generating client code in fetch, axios, Python requests, Go net/http, and Ruby.
Frequently Asked Questions
Use this online API tester. Enter your URL, choose the HTTP method, add headers or auth, and click Send. No installation or account required — everything runs in your browser.
Browsers block cross-origin requests for security. The CORS proxy routes your request through our server, adding the necessary headers so the API response reaches your browser. Enable it when you see CORS errors.
Click 'Import cURL', paste your cURL command, and the tool will parse it into a structured request. Then switch to the Code tab to see the equivalent fetch, axios, Python, Go, or Ruby code.