impact.com uses conventional HTTP response codes to indicate the success or failure of an API request. In general: Codes in the 2xx range indicate success. Codes in the 4xx range indicate an error that failed given the information provided (e.g., a required parameter was omitted, a modification failed, etc.). Codes in the 5xx range indicate an error with impact.com's servers (these are rare).

HTTP Status Code Summary

Code	Response Message	Description
200 201*	OK	Everything worked as expected.
400	BAD REQUEST	Request was unacceptable, often due to missing a required parameter.
401	UNAUTHORIZED	No valid API key provided.
403	FORBIDDEN	API key used doesn't have permissions to perform the request.
404	NOT FOUND	Requested resource doesn't exist.
405	METHOD NOT ALLOWED	Method used in the call is not supported.
429	TOO MANY REQUESTS	Too many requests hit the API too quickly. We recommend an exponential backoff of your requests.
500 502 503 504*	SERVER ERROR	Something went wrong on impact.com's end. (These are rare.)