Problem Details for HTTP APIs (RFC 7807 / RFC 9457)

When to Use

Use this skill whenever you need to implement HTTP error responses. Apply it to every REST/HTTP API regardless of language or framework.

• Adding or reviewing error handling in any REST or HTTP API endpoint
• Replacing ad-hoc { "error": "..." } JSON responses with the RFC 7807 standard format
• Implementing validation error aggregation using the RFC 9457 errors array extension
• Setting up a global error handler or middleware in Express, FastAPI, Spring Boot, or Go
• Ensuring the Content-Type: application/problem+json header is used consistently for all error responses

Standard Fields

RFC 9457 defines these fields (all optional, status is strongly recommended):