API Tester - Online REST Client
Test REST APIs online with a Postman-like interface. Configure headers, params, authentication, and request body. View response, headers, time, and size.
Keywords
API tester, REST client, HTTP client, Postman alternative, online API tool, request tester
An online REST API tester helps you craft HTTP requests, send them to endpoints, and analyze responses in one place. Use it to verify authentication headers, debug CORS problems, explore third‑party APIs, and document real examples for your team.
What is an API request?
An HTTP request consists of a method (GET, POST, PUT, DELETE, and others), a URL that identifies the resource, headers that carry metadata, optional query parameters, and an optional body for methods like POST or PUT. Authentication can be attached via headers (for example, Authorization: Bearer <token>) or other schemes.
How to use it effectively
Enter a URL, pick a method, add headers and query params, choose a body format (JSON, form‑urlencoded, multipart), and send the request. Inspect status code, response time, headers, and a pretty‑printed body. Export as cURL for scripts, and save history locally to repeat critical flows.
About the API Tester
Everything runs in your browser. CORS policies on target servers may block certain calls from web pages; in that case, test from a server or use a proxy that you control. This tool focuses on clarity and speed so you can validate behavior, explore APIs, and share reproducible examples with teammates.
FAQ
Does this tool store my requests?
Recent requests are stored locally in your browser for convenience. There is no server‑side storage.
Why did my request fail due to CORS?
Many APIs restrict browser origins. Use a server‑side script or enable CORS on the API you own to allow web‑based testing.
Use the API Tester when you need a fast, shareable way to probe endpoints, verify auth flows, or document edge cases without switching tools.
API Tester
Postman-like REST client to build requests and inspect responses