httpErrors

HttpErrors refer to HTTP responses that indicate an error condition in the client-server exchange. They are signaled by status codes in the 4xx and 5xx ranges and are distinct from successful responses (2xx).

Client errors (4xx) indicate issues with the request or authentication. Common examples include 400 Bad Request, 401 Unauthorized, 403 Forbidden, 404 Not Found, 408 Request Timeout, and 429 Too Many Requests. These codes generally mean the client should modify the request before retrying.

Server errors (5xx) indicate problems on the server side. Examples include 500 Internal Server Error, 502 Bad Gateway, 503 Service Unavailable, and 504 Gateway Timeout. These suggest temporary or persistent server issues and may warrant delayed retries by clients.

These errors are communicated via the HTTP response: a status line with the code and reason phrase, optional headers, and often a body containing further details. The body may be plain text or, for APIs, a machine-readable error object that provides more context.

Handling and design guidance: clients should handle 4xx errors as issues the user or caller must address, while 5xx errors often warrant retry logic with backoff for idempotent requests. When designing APIs, use clear status codes and consider a standardized payload such as the RFC 7807 Problem Details for HTTP APIs to describe errors with fields like title, status, detail, and instance. Including information such as Retry-After headers can aid clients during temporary setbacks.

Servers and frameworks provide built-in error handling, including default or custom error pages and middleware or controllers to generate consistent responses. Proper logging, monitoring, and alerting are essential to detect patterns of httpErrors and improve reliability.

Security and usability considerations include avoiding leakage of internal details in error bodies, providing consistent and useful messages, and ensuring accessibility and localization where appropriate.