An API endpoint is a specific URL where an API can be accessed. It's the digital location where applications send requests to retrieve or manipulate data. Each endpoint corresponds to a specific function, like /users for user data or /posts/1 for a specific blog post.

2xx (Success): The request succeeded (200 OK, 201 Created).
3xx (Redirection): Further action is needed (301 Moved, 304 Not Modified).
4xx (Client Error): The request contains bad syntax or cannot be fulfilled (400 Bad Request, 404 Not Found, 401 Unauthorized).
5xx (Server Error): The server failed to fulfill a valid request (500 Internal Server Error, 503 Service Unavailable).

CORS (Cross-Origin Resource Sharing) errors occur when a web application tries to access a resource from a different origin, and the server doesn't allow it. This is a browser security feature. To fix this, the API server must include appropriate Access-Control-Allow-Origin headers. Alternatively, you can toggle the Proxy option in this tool to route requests through a CORS proxy.

GET – Retrieve data (most common).
POST – Create new resources.
PUT – Update/replace existing resources entirely.
PATCH – Partially update resources.
DELETE – Remove resources.
HEAD – Like GET but returns only headers (no body).
OPTIONS – Discover supported methods and CORS configuration.

Response time (latency) is measured from the moment the request is sent until the first byte of the response is received. It's displayed in milliseconds (ms). Lower values indicate faster API performance. Network conditions, server load, and geographic distance all affect response time.

Yes. Add an Authorization header in the Headers section. Common formats include Bearer <token> for token-based auth, or Basic <base64-credentials> for HTTP Basic Auth. You can also add custom headers like X-API-Key if the API uses API key authentication.