Rackspace picks up startup Mailgun and its email server tools

Rackspace picked up Mailgun today, a Bay Area-based startup with a web service to create and manage email inboxes within apps.

Mailgun, a graduate of Y Combinator, announced the acquisition in the company blog this morning. The startup, which provides email server tools, also incorporates tracking and analytics that lets developers know whether emails have been opened (pictured, below).

It’s a six-person operation, but Mailgun’s early customers include Y Combinator and the Financial Times. The startup has raised $1.1 million in seed funding from SV Angel, Y Combinator, and celebrity investors like Ashton Kutcher since its launch in 2011. It will relocate from Mountain View, Calif. to Rackspace’s San Francisco offices.

Rackspace, an IT hosting company based in San Antonio, said in a statement that the deal “will further enhance Rackspace’s product portfolio, making it easy to integrate cloud-based email services into applications and websites within minutes,” adding that “our customers are asking for this and Mailgun is the right company to help us deliver it in a tightly integrated way.”

Rackspace is hot on the acquisition trail: This is its seventh buy-up. Since acquiring CloudKick in 2010, it added cloud monitoring to its suite of tools. The company is now the top cloud infrastructure provider after Amazon.

Terms of the deal were not disclosed; the acquisition is expected to close at the end of the week.