.tip

Every API invents its own error shape and every client writes a parser for each. RFC 9457 already defined one.

{
  "type": "https://example.com/errors/insufficient-funds",
  "title": "Insufficient funds",
  "status": 402,
  "detail": "Balance is 12.50, the charge was 30.00.",
  "instance": "/orders/8f2a"
}

type is a stable identifier a client can switch on. detail is for a human. Extra fields are allowed.