I get 400 BAD_REQUEST

The API did not accept the request body.

Causes and solutions

Cause	Solution
The body is not valid JSON.	Check the JSON syntax. Set Content-Type: application/json.
The number field is missing.	Add the field.
The number has fewer than 6 digits.	Send 6 to 11 digits.
The number has more than 11 digits.	Send 6 to 11 digits. Do not send full card numbers.
The number contains letters or spaces.	Send digits only.
The body is larger than 1 KB.	Remove extra fields.
The numbers array is empty or has more than 2,000 values.	Send 1 to 2,000 values.

See Single lookup: POST /v1/bin.