Error code: invalid_value_type

What triggers it

A field value was the wrong type. A nested object or array inside fields, which only accepts scalar values.

Example response

{
  "error": {
    "type": "invalid_request_error",
    "code": "invalid_value_type",
    "message": "A field value was the wrong type."
  }
}

How to fix it

Flatten the value to a string, number or boolean.

This is deterministic: the same request will fail again until fixed. See the HTTP 422 page for the class.

In practice

In a well-built client, invalid_value_type is handled by branching on error.code rather than on the human error.message, which may be reworded over time. The HTTP status (422) gives the broad invalid_request_error class; the code gives the specifics; and, on field errors, error.param pinpoints the input to fix.

This code is deterministic — retrying the identical request reproduces it — so keep it out of your retry path and instead map it to a clear, actionable message. See Map errors to user-facing messages and Read the error envelope for the pattern.