5. MailGun We find ourselves using this product in almost every application we build. Mailgun is a transactional email api service. Mailgun enables developers to send, track and receive emails via their api which is pretty basic transactional email functionality. One feature we really like is the ability to create routes to allow some basic logic around receiving an email from a specific sender. Create a route to store the email, notify a webhook in your application, get the email from Mailgun via the api and finally process the information or download the attachment… really whatever you need to do.