Introduction

For years, Microsoft Fabric has transformed how organizations collect, manage, and analyze data. Now, Microsoft is taking the next step with Rayfin—a new app development experience that enables developers to build fully interactive, data-driven web applications directly within Microsoft Fabric.

While Power BI remains the go-to platform for analytics and reporting, Rayfin expands what’s possible by allowing developers to create complete business applications powered by Fabric data. By combining AI-assisted development with familiar web technologies such as HTML, D3.js, and Plotly, Rayfin dramatically reduces the effort required to build modern data applications.

What is Rayfin?

Rayfin is Microsoft’s new application framework for Fabric that enables developers to build secure, interactive web applications without leaving the Fabric ecosystem.

Rather than creating static dashboards, you can develop rich applications that allow users to interact with data, perform actions, and experience highly customized interfaces—all while leveraging the security, governance, and scalability of Microsoft Fabric.

The real innovation is its agentic development model, where AI coding assistants work alongside developers to generate, modify, and optimize applications using natural language prompts.

Getting Started with Rayfin

Before you begin building, you’ll need a few prerequisites.

Microsoft Fabric Capacity

Rayfin is available on Microsoft Fabric capacities starting from F2 and above, making it accessible for both development environments and enterprise deployments.

Enable App Preview

An administrator must enable the App Preview feature within the Power BI Admin Portal before developers can create Rayfin applications.

Development Tools

To get the best experience, you’ll need:

• Visual Studio Code
• Node.js and npm
• An AI coding assistant such as GitHub Copilot or Claude Code

These tools form the foundation of the agentic development workflow.

Creating Your First Rayfin App

The development experience combines Microsoft Fabric with local development in Visual Studio Code.

1. Create an App Item

Inside your Fabric workspace, select New Item and choose App to create a new project.

2. Choose a Starting Template

Rayfin currently offers starter templates including:

• To-do App connected to a Fabric SQL database
• Data App connected to a Power BI Semantic Model

These templates provide a solid starting point for rapid application development.

3. Generate the Project

From the VS Code terminal, initialize your application using:

npm create rayfin@latest

This downloads the complete project structure and prepares your local development environment.

4. Initialize Git Immediately

One of the strongest recommendations is to initialize a Git repository as soon as the project is created.

Because AI agents can generate and modify hundreds of files during development, version control makes it easy to review changes, recover previous versions, and safely experiment with new ideas.

Building Apps with AI Agents

Rayfin is designed around AI-assisted development.

Instead of manually editing every line of code, developers can instruct AI agents using natural language.

For example, you might ask an agent to:

• Move the login button into the page header
• Add a dark mode toggle
• Create a responsive navigation menu
• Generate new visualizations
• Improve the application’s layout

The AI performs the implementation while you focus on the user experience and business requirements.

Smarter Development with Semantic Models

Rayfin also supports Model Context Protocol (MCP) servers.

This allows AI agents to understand your Fabric semantic models, including tables, relationships, and measures.

Rather than manually writing DAX queries, you can simply describe the analysis you need, and the AI can generate appropriate queries based on the model schema.

It’s a significant productivity boost for developers working with complex enterprise datasets.

Performance and Security Best Practices

Scale Compute for Development

One important optimization is managing SQL compute resources.

By default, Fabric SQL databases may provision 32 virtual cores, which can quickly consume the resources available on an F2 capacity.

For development and testing, reducing this allocation to 2–4 virtual cores helps minimize capacity usage while maintaining a responsive development experience.

Built-In Security

Rayfin applications inherit Microsoft’s enterprise security model.

Applications securely communicate between the front end and Fabric data sources without requiring developers to configure manual application registrations or authentication flows.

This simplifies deployment while maintaining enterprise-grade security.

Authentication

Users authenticate using their Microsoft Fabric identities, ensuring access remains governed by existing organizational permissions and security policies.

Current Limitations

As Rayfin is currently in public preview, there are a few limitations to be aware of.

At present:

• Only Fabric SQL Databases and Power BI Semantic Models are supported as data sources.
• Lakehouses and Warehouses cannot yet be queried directly.
• Custom domains are not currently available.
• Environment variables for securely storing secrets are not yet supported.
• Integration with Fabric User Defined Functions (UDFs) and portions of the Fabric REST API is still evolving.

These limitations are expected to improve as Microsoft continues to develop the platform.

The Future of Data Application Development

Rayfin represents far more than another development framework—it signals Microsoft’s vision for the future of building business applications.

Instead of spending weeks hand-coding user interfaces, configuring authentication, and connecting data sources, developers can leverage AI agents to automate much of the development process while focusing on delivering business value.

For organizations already investing in Microsoft Fabric, Rayfin offers an exciting opportunity to move beyond dashboards and create intelligent, interactive applications that place data directly into users’ hands.

As agentic development continues to evolve, Rayfin has the potential to fundamentally change how data professionals build software—making application development faster, more accessible, and more closely aligned with the way people naturally work.