Returning RFC 9457 Problem Details from Go Validation Errors
How to turn struct-tag validation failures into a standard "application/problem+json" response — the RFC 9457 format — with one method call, no hand-rolled error envelope. Most Go APIs invent their own validation error shape. One team returns {"errors": [...]} , another {"field_errors": {...}} , a third just a flat {"error": "message"} and hopes the client parses it. Every one of those is a…
Checker now provides a standard RFC 9457 format response for Go validation errors, simplifying the process of returning structured error information in a consistent way. The RFC 9457 format includes four base members: type, title, status, and detail (instance), with the option for problem-specific extensions. Checker can generate these responses directly from failed struct validation using the CheckErrors.ProblemDetails() method.
This results in a single method call that generates an application/problem+json body with the necessary structure. The output includes a type, title, status, and an invalid-params array listing the fields that failed validation along with their reasons and codes. By using Checker's CheckStruct() method, developers can easily convert validation errors into a properly formatted problem+json response without having to manually construct the envelope.
The defaults for the problem details are set to RFC 9457's own defaults, but these can be overridden if needed. Localized error messages are also supported, with the ability to specify a different locale if desired. Adopting this standard format for error handling in Go APIs can improve interoperability, simplify error handling for clients and API gateways, and reduce the need for custom error shapes across different services.
Written by urgent.news from Dev.to's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
