Stop Inventing Your Own API Error Format: Use RFC 9457 Problem Details
Every API eventually grows its own snowflake error format. One endpoint returns {"error": "not found"}, another returns {"message": "Not Found", "code": 404}, and a third buries the real reason in a 200 OK with {"success": false}. Clients end up writing brittle, per-endpoint parsing logic just to figure out what went wrong.
There is a standard that fixes this: RFC 9457 — Problem Details for HTTP APIs (the update to the older RFC 7807). It defines a single, predictable JSON shape for errors, with a registered media type. If you adopt it, any client — including generic tooling — can understand your errors without custom code.
The shape
A Problem Details response uses the application/problem+json content type and a small set of standard fields:
