Mailgun has been built in order to let people interact with their favorite applications by using their email clients. The premise here is turning email into an alternative UI for applications. Using Mailgun, developers can give any page or feature in their apps its own email address. This means that users of the application will be able to receive and send emails right from the app. They will also be able to search and forward them straightaway.
Technically, this is achieved by combining SMTP, POP3 and IMAP. And the company also uses its very own HTTP REST API in order to let people program these virtual email servers within their applications.
Mailgun can be tried for free, and if you think that such a service is what you need to take your application to the next level then you can sign up for any of the three paid plans on offer. Essentially, you will be charged based on the actual resources that you consume (IE, the number of messages that are received and sent). But bear in mind that a minimum monthly fee has to be paid in every case.
Mailgun.net In Their Own Words
Mailgun was built to scratch our own itch: prior to Mailgun, we kept hearing from our business users how great would it be to interact with our apps directly from their email clients and using their Blackberries and smartphones. We realized that email itself is an alternative UI for apps and there is a lot more to it than just sending newsletters and forgotten password recovery emails!
Why Mailgun.net It Might Be A Killer
Email is the basic form of online communication, and a mailbox API such as this one makes for the development of applications where it becomes more integrated than ever.
Some Questions About Mailgun.net
In which ways is the free plan limited? 
