# 40001: Invalid request body

Identifier: `invalid_request_body`



The body of the request could not be processed because it was invalid, missing required fields, or not in the expected format.

## What you should do

Correct the request body so it matches what the endpoint expects, then resend. Start from the accompanying error message: it names the specific problem, such as a field of the wrong type or a missing required field.

## Why it happens

The body of the request could not be parsed or failed validation. Common cases are a malformed or non-JSON body, a missing required field, or a value of the wrong type. It most often appears on token requests, where a field is absent or not in the expected form.

## What you'll see

The error is reported with code 40001 and HTTP status 400. The message varies with the cause and usually names the offending part, for example `invalid request body: ...`.