MailUp API - REST use OAuth v2 as authorization and authentication system to validate access to resources.
What is OAuth v2?
OAuth v2 is the next evolution of the OAuth protocol which was originally created in late 2006. OAuth v2 focuses on client developer simplicity while providing specific authorization flows for web applications, desktop applications, mobile phones, and living room devices.
This specification is being developed within the IETF OAuth WG and is based on the OAuth WRAP proposal.
The main framework was published in October 2012.
The OAuth v2 Framework was published as RFC 6749, and the Bearer Token Usage as RFC 6750.
Why OAuth v2?
There are several good features that makes OAuth v2 a preferable authentication and authorization process to interact with MailUp services and resources. First of all is simplicity. While old token authentication system was based on heavy client operation in generating valid tokens and keys (process that was not only difficult to implement for external developers but to support too), the OAuth v2 system is virtually total server based.