errors-and-status-codes

HTTP 400 indicates malformed syntax, while 422 signifies semantic validation errors. This Skill provides guidance on differentiating between 400 and 422 to ensure correct status code selection for API error responses.

You structure API error responses using RFC 9457 Problem Details to create a standardized JSON envelope. This Skill defines a consistent error structure that helps developers integrating with your API easily understand and handle issues.

HTTP 401 indicates missing or invalid authentication, whereas 403 means the authenticated user lacks permissions. This Skill covers best practices for 4xx error categorization, including differentiating between 401 and 403.

You return per-field validation errors by detailing specific issues for individual fields within the request body. This Skill provides comprehensive guidance on incorporating these detailed validation errors into your API error responses.

Use 4xx status codes for client errors and 5xx for server-side failures. This Skill covers best practices for 4xx and 5xx error categorization to help you choose the most appropriate code.

You add request and trace IDs to API error responses to improve debuggability and supportability. This Skill provides comprehensive guidance on incorporating these identifiers into your standardized error envelopes.