Wednesday morning in San Francisco, at Microsoft's annual "Build" developer conference, CEO Satya Nadella will make the case that companies should focus their engineering resources on the tech giant's platforms such as Windows and Azure.
If Nadella doesn't win over the roughly 5,000 attendees, then these developers could instead choose to write applications for rivals. There's billions of dollars on the line in an explosively growing market.
For example, just last week, Amazon reported that Amazon Web Services–its cloud business–is worth $5 billion and boasts better margins than analysts had expected.
Oracle is also swinging for Microsoft's business. Larry Ellison's company says its cloud revenue is already above a $2 billion run rate.
On the mobile front, Nadella will tout the advantages of Windows 10, the new version of its operating system.
The appeal for developers is that Windows 10 is a unified, single operating system that works across smartphones, tablets and PCs.
Financial analysts covering Microsoft hope to hear on Wednesday more about Windows 10, including monetization plans, the product road map for key enterprise servers and services, and what Nadella's intentions are for the next phase in cloud services.