The battle for customers continues, and Microsoft Azure (MSFT) has scored a big one over Rackspace (RAX). As Steve Guggenheimer, corporate vice president of Developer Platform and Evangelism and chief evangelist for Microsoft, detailed in a blog post, educational game developer JumpStart has shifted its infrastructure entirely to Azure from on-premise infrastructure and the Rackspace cloud.

According to Guggenheimer (who refers to himself as "Guggs" on his blog), the game developer "needed a more robust backend to support its growing demand and decided to migrate from Rackspace to Microsoft Azure. Timed with the anticipated NFL titles, JumpStart migrated its most popular titles to Microsoft Azure to support their massive gaming needs, without disrupting their customers’ gaming experience."

JumpStart is known for games such as NFL RUSH GameDay Heroes, School of Dragons and Madagascar Math Ops. It has been developing games aimed at children for more than 20 years, and it has begun transitioning to cloud in recent years to more rapidly scale across the many devices it develops for and supports, as well as to support a growing number of simultaneous sessions of its cloud-based games.

"JumpStart's complete migration to Microsoft Azure means that they will no longer have any on-premises servers supporting their games or apps," wrote Guggenheimer. "The company is running Linux images on Microsoft Azure, as well as Windows Server and SQL Server. By allowing Microsoft Azure to handle backend information, provisioning mobile services to bolster seamless gameplay, the company can focus more energy on what it does best—creating great education games for kids."

JumpStart CEO David Lord explained the shift to Azure in an announcement made on the company's website.

"As a company, it is crucial we continue to adapt to our growing user base," said Lord in a prepared statement. "We have millions of users around the world logging into our games at all hours. That being said, Microsoft Azure is absolutely the right platform for us—it provides us the scalability and flexibility we need to help our games run smoothly for our users."

It's a sound endorsement of the Azure cloud. And it's a solid win for Microsoft, particularly over rival Rackspace.