/fabric-apps — Rayfin SDK for Fabric Apps

Fabric Apps turns Microsoft Fabric into a full-stack application backend. The Rayfin SDK (MIT licence, TypeScript-first) lets a developer define a data model in TypeScript, run one CLI command, and have Fabric provision a SQL database, GraphQL API, Entra ID auth, access policies, static hosting, and OneLake routing automatically.

STATUS: Public Preview — Build 2026, June 2026. No SLA. No GA date published as of September 2026. Not all regions. Fabric tenant admin must enable the Fabric Apps workload before any development can begin. Client conversation on Preview status is mandatory before any production packaging.

When to invoke

• Client wants a packaged, data-driven web application backed by Microsoft Fabric
• Project needs a write-back UI on top of Power BI semantic models with governed business logic
• Agent-first app where operational data must route automatically into the full Fabric stack (Spark, Power BI, Real-Time Intelligence)
• FDE PoC on Fabric where TypeScript model → deploy CLI is the right acceleration path
• Client asks about "Fabric Apps" or "Rayfin" — verify they mean the Rayfin SDK surface, not the older Fabric Apps item-bundling concept

Steps

1. Admin pre-requisite check. Fabric tenant admin must enable the Fabric Apps workload in the Fabric admin portal. Scope can be set to the full organisation or specific security groups — no waitlist, it is a tenant toggle. Verify the toggle is on before starting. Verify region availability for the client's Fabric tenant — not all regions are supported as of June 2026. If the region is unsupported, escalate to Nexus for a platform brief before scoping.
2. Install Rayfin CLI. Verify the current package name and install command at author time — the SDK is actively developed and package names may shift before GA.

   # verify current package name at author time against Microsoft Learn / Rayfin SDK docs
   npm install -g @microsoft/rayfin-cli

3. Define the TypeScript data model. Create type definitions describing the application's data entities. The CLI uses these to generate the SQL schema, GraphQL schema, and access policies automatically. Keep entity types simple on first pass — complex relations can be added incrementally.
4. Initialise the Fabric App.

   # verify current CLI command at author time
   fabric-apps init

   This scaffolds the project structure and registers the app against the Fabric workspace.
5. Configure OneLake routing, Entra auth, and GraphQL/SQL access. Rayfin auto-generates routing from the TypeScript model, but review:
   • OneLake workspace and path mapping
   • Entra ID app registration (auto-created — review permission scopes)
   • GraphQL API schema and any custom resolvers needed
   • Access policies (who can read/write each entity)
   • Anonymous data access flag — August 2026 feature; enable for public-facing experiences that do not require sign-in
6. Deploy.

   # verify current CLI command at author time
   fabric-apps deploy

   Fabric provisions the SQL database, GraphQL API, static hosting, and OneLake routing in one command.
7. Validate. Confirm the deployed Fabric App URL is reachable, the Entra app registration has the correct redirect URIs, and OneLake data is flowing. Run at least 3 representative write operations and verify they appear in OneLake.
8. Power BI semantic model binding (if required). If the app writes to OneLake data that a Power BI semantic model reads, verify Direct Lake mode picks up the new data. Check workspace-level roles (Admin/Member/Contributor/Viewer) for the semantic model.

Deliverable format

• Deployed Fabric App URL — documented with an environment note flagging Preview status
• Entra ID app registration record (client ID, redirect URIs, permission scopes)
• TypeScript model source committed to Git
• OneLake mount documentation (workspace, path, access policy summary)
• Client sign-off note on Preview status — dated and named

Non-negotiables

• Preview flag is mandatory with client before any production packaging. Client must explicitly acknowledge that Fabric Apps is Public Preview, carries no SLA, and Microsoft may introduce breaking changes. Get this on record before the engagement closes.
• Admin pre-requisite confirmed before scoping. If the Fabric tenant admin has not enabled Fabric Apps, development cannot start. Verify at kick-off — not after sprint 1.
• Region check at brief time. Not all Azure regions support Fabric Apps. Verify tenant region eligibility at Nexus platform brief stage before committing to a Rayfin build.
• Verify CLI commands and package names at author time. The Rayfin SDK is actively maintained; command syntax may change before GA.
• No production SLA promises. Do not commit to uptime, latency, or reliability SLAs for any Fabric App component while the feature remains Public Preview.

References

• What is Fabric Apps (Preview)? — Microsoft Learn — verify current at author time
• Create and deploy your first Fabric app with the Rayfin CLI — Microsoft Learn — verify current at author time
• Fabric August 2026 Feature Summary — anonymous data access addition
• Introducing Rayfin — Microsoft Fabric Community
• Athanasios recon: .squad/coach/knowledge/2026-09-04-enterprise-integration-recon.md (Angle 1)
• Decision: .squad/decisions/2026-09-04-nexus-enterprise-integration-extension.md