Response

A successful request can answer that an input is invalid. For example, Phone and IBAN can return 200 with valid: false when parsing or a checksum fails. Email rejects malformed addresses with 400. Check the fields as well as the HTTP status.

false

A negative answer to that field's question. valid: false does not mean the request failed.

null

No answer is available for that field. Keep it distinct from false, zero, or an empty string.

Omitted

The field is not part of this response. For example, deep is absent unless requested.

Each endpoint explains its fields, supported inputs, and coverage. Handle missing answers explicitly and allow new fields to be added to the response.