Rayfin

What is Rayfin?

Rayfin is a service that helps teams build and ship applications faster. It does this by taking care of the backend infrastructure for them. Microsoft announced Rayfin at Build 2026. With Rayfin, developers can define their application backends using code. This includes data models, business logic, and access policies.

Here's how Rayfin works:

• Define: Developers write code to describe their application backend using the Rayfin SDK. This code includes data models, APIs, access policies, business logic, and connections to existing data sources.
• Deploy: When the app is ready, the CLI sends it to Microsoft Fabric. This sets up everything the backend needs like databases and authentication.
• Run: The application runs inside Fabric. It gets governance, security, and compliance from the platform.

Key Features

• Rayfin provides a backend with database, authentication, and app hosting.
• Data is stored in the organization's trusted data estate by default. This means it inherits governance, security, and compliance foundations already established in Fabric.
• Rayfin supports a local development experience with no cloud resources required.

Rayfin Starter Templates

Rayfin offers four starter templates to help developers get up and running quickly:

Template	Best For	What It Includes
Data App	Analytics & dashboards	Connects to a Power BI semantic model and queries it via DAX. Ideal for building interactive data visualizations and dashboards using libraries like Vega-Lite or D3.js. Best suited for data analysts who need to explore and present data insights.
Todo App	Simple task management	A basic task management app with database and authentication pre-wired. Perfect for individuals or teams who need a ready-to-use task tracking solution without any custom setup.
Todo with Docs	Task + document workflows	Extends the Todo app with document handling capabilities, useful for content-driven workflows.
Blank App	Custom builds from scratch	A minimal scaffold with no pre-built logic. Best for developers who want full control over their app structure, data sources, authentication, and design. Start from zero and build exactly what you need.

Example

A retail company wants to build an internal inventory management app. Normally this would take weeks. They would have to set up servers, configure databases, and manage authentication systems separately.

With Rayfin, a developer defines the backend using TypeScript decorators in the Rayfin SDK to describe product data models, user access policies, and inventory APIs. Running a CLI command deploys the app directly to Microsoft Fabric.

The app instantly inherits the company's existing enterprise security and compliance rules and is production-ready within hours, not months.

With Rayfin, the gap between building an idea and shipping it to production is no longer measured in months but it's measured in hours.