Response Codes

legacy api — sunsets june 1, 2027 this page documents the original mailfloss api, which is being retired on june 1, 2027 new integrations should use the v1 api https //developers mailfloss com/quickstart the api makes use of standard http response codes to indicate the success or failure of a request the 2xx series of response codes indicate success, 4xx indicates an error from the client side, and a 5xx error indicates a server side error please check response codes and handle accordingly contact us if you run into repeated issues, especially in the 5xx error range here are the http response codes the mailfloss api utilizes 200 success 400 email address or id not supplied 401 invalid api key 402 insufficient credits 403 no api key provided 404 job not found or job not finished 405 method not allowed 413 payload too large too many email addresses 414 request entity too large 415 invalid content type must be application/json 429 rate limit exceeded 500 timeout 502 bad gateway 503 failed to create job 504 gateway time out