Microsoft will let anyone use the cloud technology behind the Xbox
Responding to a question on Twitter, Spencer said that "Azure services are available to any game, even other platform's exclusives." He continued that Microsoft "wouldn't keep [a developer] from using [it]."
Azure is a cloud-based platform that allows developers to build, develop, and deploy software using data centres, which Microsoft manages. This makes it easier for smaller scale companies to operate on a bigger scale without having to worry about the complexities - and costs - of running a big data centre.
Amazon, which has the Amazon Web Services product, and Microsoft are currently locked into a cloud war, competing for customers in the US, Europe, and elsewhere. The European market for cloud services and storage is valued at $11 billion (£7.3 billion) annually, according to analysts.
Microsoft CEO Satya Nadella has said that the company's mission is to "empower every person and every organization on the planet to achieve more" and opening up Azure to game developers is part of that aim.