Microsoft Unveils Rayfin as New Backend Platform for AI Apps

Microsoft has a new idea for how enterprise applications should be built, and it starts with AI-generated code. During Build 2026, the company introduced Rayfin, an open-source SDK and command-line tool designed to simplify backend development for modern applications.

Microsoft wants backend development to be code first

Microsoft says that AI tools can generate application frontends in seconds, but building secure, scalable backends still requires developers to connect databases, authentication systems, APIs, governance controls, and enterprise data sources manually. Well, Rayfin is designed to close that gap.

With Rayfin, developers and coding agents can define an entire backend using code. That includes databases, APIs, business logic, identity controls, access policies, and integrations with existing enterprise systems. Once completed, applications can be deployed directly into Microsoft Fabric, where they inherit security, compliance, governance, and analytics capabilities from the platform.

Microsoft says this approach allows teams to move from prototype to production much faster while keeping enterprise requirements intact from day one.

Rayfin could become a key piece of Microsoft’s AI strategy

One notable aspect of the announcement is Microsoft’s partnership with Replit. Developers can continue building applications inside Replit’s AI-focused environment while deploying those projects directly into Microsoft Fabric using Rayfin. The goal is to combine rapid development with enterprise-grade governance and data management.

Moreover, Rayfin fits perfectly into Microsoft’s broader AI strategy. Alongside Project Solara, new Aion AI models, AI-powered Windows 365 upgrades, and Surface RTX Spark hardware, Microsoft continues pushing toward a future where AI helps build, manage, and deploy software at every stage of development. Not to forget, the company has also shared new tools to secure code, agents, and AI models.