The Cosmic JS API uses the following error codes:

Error Code Meaning
200 OK - Everything worked as expected.
400 Bad Request - Your request is invalid.
401 Unauthorized - Your access key is incorrect.
402 Payment Required - Your Bucket needs to be upgraded to continue use.
403 Forbidden - You are not allowed to access this content.
404 Not Found - The requested resource doesn't exist.
429 Too Many Requests - Too many requests hit the API too quickly.
500, 502, 503, 504 Internal Server Error - Something went wrong on our end.