Problem+JSON

Some gateway handlers return RFC 7807 Problem Details responses with a consistent JSON shape and an optional trace identifier.

Deep dive:

• Problem implementation: Problem

See also:

• Server middleware: Middleware
• Guide: Troubleshooting

Content type

Problem responses use:

• application/problem+json

Response schema

The gateway uses a small superset of RFC 7807:

{
  "type": "about:blank",
  "title": "Payload Too Large",
  "status": 413,
  "detail": "Request body exceeds 1048576 bytes",
  "instance": "/v1/trade/orders",
  "traceId": "31635592-fc56-4b8f-bf39-9ae21ebce8c9"
}

Notes:

• traceId is included when the request has a trace ID available.
• instance is typically the request path.

When it is used

Middleware and handlers use problem responses for consistent error UX, for example:

• request body too large (413)
• rate limit exceeded (429)
• CORS rejected (403)