The very first REST API request must be to authenticate to a specific Responsys account using a username and a password or certificates. Upon successful authentication, a token and an endpoint are returned that you must use for any subsequent REST API request. Before the token expires, you can refresh the token so that you will not need to re-authenticate.

Transport Layer Security support: Ensure that your client systems use Transport Layer Security (TLS) version 1.2.

See the Responsys Bulletin for more information.