Problem Details - RFC 9457

Choose the error contract

Inspect existing advice, security entry points and API tests first. Keep one error policy per API. Success DTOs or success envelopes can coexist with Problem Details errors: RFC 9457 specifies errors, not success representations.

For an API using Problem Details, enable Spring's built-in MVC exception handling:

spring:
  mvc:
    problemdetails:
      enabled: true

For WebFlux use spring.webflux.problemdetails.enabled and reactive exception handling; the servlet templates below are not WebFlux handlers.