Bellissima: The New Backoffice Architecture
Umbraco v14 introduced Bellissima, the most significant architectural change in Umbraco history: a complete rewrite of the backoffice from AngularJS to Web Components. With Umbraco v17 LTS (released November 2025), Bellissima reached production maturity on .NET 10 LTS.
If you’re planning an Umbraco upgrade, evaluating Umbraco for a new project, or trying to understand what Bellissima actually means for your team, this page provides practitioner-level context: what changed, why it matters, and what the new architecture looks like.
What Is Umbraco v14 (and Why It Matters)
Section titled “What Is Umbraco v14 (and Why It Matters)”Umbraco v14 launched in May 2024 with a single, transformative goal: replace the decade-old AngularJS backoffice with a modern, maintainable architecture. The result is Bellissima, a complete backoffice rewrite using Web Components, Lit, and TypeScript.
Why This Is the Biggest Breaking Change in Umbraco History
Section titled “Why This Is the Biggest Breaking Change in Umbraco History”For Umbraco developers, v14 represents a fundamental shift:
- All custom AngularJS property editors must be rewritten as Web Components
- Custom dashboards and backoffice extensions require migration to the new Extensions API
- AngularJS-based community packages needed v14-compatible updates (many took months)
- Developer skillset requirements changed: TypeScript and Web Components replace AngularJS knowledge
This isn’t a UI refresh. It’s a new foundation.
Umbraco v17 LTS: Why It Matters More Than v14
Section titled “Umbraco v17 LTS: Why It Matters More Than v14”While v14 introduced Bellissima, v17 LTS (November 2025) is the version practitioners should target:
- Built on .NET 10 LTS — long-term support through 2028
- Bellissima matured — bugs fixed, performance improved, accessibility enhanced
- 3-year support window — enterprise-grade stability for projects planning multi-year lifespans
- Recommended for new projects — skip v14 unless you’re already on it
The pattern: v14 was the brave early adopter release. v17 LTS is the stable foundation enterprises should build on.
What Is Bellissima?
Section titled “What Is Bellissima?”Bellissima is Umbraco’s modern backoffice, replacing the AngularJS-based UI that powered Umbraco since v7. The name “Bellissima” (Italian for “most beautiful”) signals ambition: create a backoffice that’s fast, accessible, and extensible for the next decade.
Technology Stack
Section titled “Technology Stack”| Component | Technology | Purpose |
|---|---|---|
| UI Framework | Web Components | Framework-agnostic component model |
| Component Library | Lit (lightweight library) | Simplifies Web Component authoring |
| Language | TypeScript | Type safety, modern JS features |
| UI Library | Umbraco UI Library | Shared component system (buttons, inputs, modals) |
| State Management | Context API + observables | Reactive state across components |
| API | Management API | REST API for backoffice operations |
Why Web Components?
Section titled “Why Web Components?”Web Components are browser-native, framework-agnostic building blocks. Unlike AngularJS (tied to Angular 1.x), Web Components work with any framework — or no framework at all.
Benefits:
- Future-proof: Part of web standards, not tied to a framework’s lifecycle
- Performance: Native browser support, no framework overhead
- Extensibility: Developers can use their preferred tools (React, Vue, vanilla JS)
Trade-off:
- Migration cost: All AngularJS custom code must be rewritten
Management API: Headless Content Management
Section titled “Management API: Headless Content Management”Bellissima introduces the Management API, a REST API for creating and managing content programmatically. This complements the existing Content Delivery API (read-only).
What It Enables:
- External systems can create, update, and delete content
- Automated content workflows (e.g., sync from PIM, DAM push to Umbraco)
- Headless content management (manage Umbraco content from external tools)
Authentication:
- OAuth 2.0 / OpenID Connect
- API keys for service-to-service communication
Example Use Case: A product information management (PIM) system automatically creates Umbraco product pages when new products are added, pushing product data via Management API.