Victor Ciura, Microsoft's principal engineer for the Rust tooling team, announced during his RustConf keynote that Rust now enjoys first-class support across the entire software development lifecycle. The company has built a paved path of tools and processes to support local Rust development, with Rust already present in over 100 Microsoft project repositories.
Microsoft has developed Oxidizer, a set of crates for building scalable services in Rust. These have been used to construct and refine core Microsoft 365 services including Outlook, Word, Excel, OneDrive, and SharePoint. The Copilot tech stack also relies heavily on Rust.
On the tooling front, Microsoft engineers have built rustc_codegen_utc, a custom Rust compiler code-generation backend that wires the rustc compiler directly into the MSVC toolchain for Windows. This ensures perfect compatibility out of the box rather than requiring a parallel implementation of Windows-specific capabilities.
Despite the integration, challenges remain. RustConf attendees grappled with the dangers of mixing Rust and C++ code, particularly in "unsafe" territory where the Rust compiler cannot track pointers into C++ memory allocations.
Memory safety remains a driving force behind Microsoft's investment. In his 2025 RustConf keynote, Microsoft Azure CTO Mark Russinovich noted that approximately 70 percent of Windows CVEs are memory issues. “One of the things that I realized a long time ago is that no matter how much we really want to make C and C++ better, we can't make it as good as what Rust starts with,” he said.