Flask Academy · Lesson

Uniform JSON Error Envelopes

Standardize error shape for API clients.

One Shape for Every Error

Mixed error formats confuse clients. A uniform envelope means every failure looks the same, so apps parse it once and trust it.

A good envelope carries a stable error message and a code. Clients read these fields instead of guessing from raw text.

{
  "error": "Not found",
  "code": 404
}