📡 HTTP Status Codes

Use case: Used when the client needs to send a large request body.

Use case: Used when upgrading from HTTP to WebSocket.

Use case: Used for long-running requests to prevent timeout.

Use case: Allows browser to preload resources while server prepares response.

Use case: Standard response for successful HTTP requests.

Example: GET /api/users

Use case: Returned after successfully creating a resource.

Example: POST /api/users

Use case: Used for asynchronous processing.

Example: POST /api/jobs

Use case: Used for successful DELETE requests or updates that don't return data.

Example: DELETE /api/users/123

Use case: Used for partial content requests (e.g., video streaming).

Example: GET /api/video with Range header

Use case: Use when a resource has permanently moved to a new location.

Example: Old URL redirects to new URL

Use case: Temporary redirect, commonly used for login redirects.

Example: Redirect after login

Use case: Used with conditional GET requests to save bandwidth.

Example: GET with If-Modified-Since header

Use case: Similar to 302 but preserves HTTP method.

Example: POST redirect preserving method

Use case: Similar to 301 but preserves HTTP method.

Example: Permanent redirect preserving method

Use case: Return when request syntax is invalid or missing required parameters.

Example: Invalid JSON in request body

Use case: Return when authentication is required or has failed.

Example: Missing or invalid API token

Use case: Return when user is authenticated but lacks permission.

Example: User tries to access admin resource

Use case: Return when the requested resource does not exist.

Example: GET /api/users/999 (user doesn't exist)

Use case: Return when HTTP method is not supported for the endpoint.

Example: POST to GET-only endpoint

Use case: Return when server cannot satisfy Accept header requirements.

Example: Client requests XML but server only has JSON

Use case: Return when there is a conflict (e.g., duplicate email).

Example: Creating user with existing email

Use case: Return when resource existed but is permanently removed.

Example: Deleted resource that won't be restored

Use case: Return when request body exceeds size limit.

Example: File upload exceeds 10MB limit

Use case: Return when URL exceeds maximum length.

Example: GET request with extremely long query string

Use case: Return when Content-Type is not supported.

Example: Sending XML when server expects JSON

Use case: Return when validation fails (e.g., invalid email format).

Example: POST with invalid email address

Use case: Return when rate limit is exceeded.

Example: More than 100 requests per minute

Use case: Return for unexpected server errors.

Example: Unhandled exception in server code

Use case: Return when server doesn't support the requested feature.

Example: Server doesn't support requested HTTP method

Use case: Return when gateway/proxy receives invalid response.

Example: API gateway receives error from backend

Use case: Return when service is temporarily unavailable.

Example: Server is down for maintenance

Use case: Return when upstream server times out.

Example: Database query exceeds timeout

Use case: Return when HTTP version is not supported.

Example: Client uses HTTP/3 but server only supports HTTP/1.1