SendGrid's cloud-based email helps keep emails out of spam folders, provides a cloud service that scales with email demands, and provides email analytics to track opens and clicks.
The Customer Subuser API allows developers to integrate user management functionality into their applications. The API exposes email list managment methods including bounce records, unsubscribe notices and spam reports. Limits can also be set on the amount of emails that users can send, event notifications can be managed and users can be logged in and authenticated. The API RESTful calls and responses are formatted in XML and JSON.