Umbraco Mocked Backoffice

This lets you run the Umbraco backoffice UI with mocked APIs so you can test extensions without spinning up a .NET backend. Right now it only works from within the Umbraco CMS source repo, but it's waiting on an upstream update to support external extensions. You get two mocking strategies: MSW handlers for network-level testing (error states, retries) or mock repositories for predictable data flows. The skill walks through setting up Playwright tests, configuring environment variables, and getting the dev server running with your extension loaded. If you're building Umbraco extensions and want faster iteration cycles without backend deployment, this is the pattern to follow once the external extension support lands.

skills.sh installs: 382
GitHub stars: 27
last updated: Aug 21, 2026

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Install

$ npx -y skills add umbraco/umbraco-cms-backoffice-skills --skill umbraco-mocked-backoffice --agent claude-code

Installs into .claude/skills of the current project.

Files

Umbraco Mocked Backoffice

Status: This skill is currently awaiting an update from Umbraco to allow external extensions to use the mocked backoffice. The patterns documented here work when running from within the Umbraco-CMS source repository.

Run the full Umbraco backoffice UI with all API calls mocked - no .NET backend required.

When to Use

Visually test extensions during development
Rapid iteration without backend deployment
Test extensions in realistic UI environment
Demonstrate extensions without infrastructure
CI/CD testing without backend setup

Related Skills

umbraco-example-generator - Set up extensions for mocked backoffice (start here)
umbraco-testing - Master skill for testing overview
umbraco-unit-testing - Test extension logic in isolation
umbraco-e2e-testing - Test against a real Umbraco instance