unknown_field

HTTP status: 400

The request body contains a field name that the API schema does not recognize. The API rejects unknown fields instead of silently ignoring them.

Why this happens

• A field was renamed in a newer SDK version and the old name is still being sent (e.g., gender after the sex migration in SDK v0.5.1).
• The request was hand-crafted or built from outdated documentation.
• A typo in the field name.
• You are sending a field that is valid on a different endpoint.

What to do

1. Read the param field in the error response — it contains a JSON Pointer (e.g., /gender) identifying the unknown field.
2. Remove the field or rename it to the current canonical name.
3. Consult the API Reference for the current field list for the endpoint you are calling.
4. If you are using an SDK, upgrade to the latest version — the SDK enforces current field names at the type level.

Example response

{
  "type": "https://zyins.isaapi.com/errors/unknown-field",
  "title": "Unknown field",
  "status": 400,
  "detail": "Request body contains an unknown field '/gender'. The canonical field name is 'sex' (since v0.5.1).",
  "code": "unknown_field",
  "advice_code": "remove_or_rename_field",
  "param": "/gender",
  "request_id": "req_01HZK2N5GQR9T8X4B6FJW3Y1AS"
}

SDK exceptions

See also

• Error catalog
• API Reference