Amazon Web Services (AWS) has put its Workmail email and calendaring service on general release. Priced at $4 a month it includes an Exchange migration tool to encourage defections by Microsoft customers. However, those with data sovereignty issues should be aware that the services are mostly being hosted in the US, with a solitary non US data centre in Eire.

After a year in preview, the service was announced on the blog of AWS chief evangelist Jeff Barr. The service, designed to work with existing desktops and mobile clients, has been strengthened since it emerged in preview form, with the new service offering greater security, ease of use and migration, Barr said. The system has an emphasis on mobility features, with location control and policies and actions for controlling mobile devices, along with regular security features such as encryption of stored data, message scanning for spam and virus protection.

The migration tool will make it easier for users to move away from Microsoft Exchange, according to Barr, which suggests that dissatisfied Exchange users could be the primary target market.

The $4 per user per month service comes with an allocation of 50GB of storage and will be run from AWS’ US data centres in Northern Virginia and Oregon (in the US), with a single data centre in Eire to service European customers. “You can choose the region where you want to store your mailboxes and be confident that the stored data will not leave the region,” wrote Barr.

Other features include a Key Management Service (KMS) for creating and managing the keys that are used to encrypt data at rest and Self Certifications, so that WorkMail users can show they have achieved various ISO certifications.

WorkMail will support clients running on OS X, including Apple Mail and Outlook. It will also support clients using the Microsoft Exchange ActiveSync protocol including iPhone, iPad, Kindle Fire, Fire Phone, Android, Windows Phone, and BlackBerry 10. AWS is also working on interoperability support to give users a single Global Address Book and to access calendar information across both environments. A 30-day free trial is available for up to 25 users.