Get started

For most users, Cloudflare recommends using the Workers Vitest integration for testing Workers and Pages Functions projects. Vitest ↗ is a popular JavaScript testing framework featuring a very fast watch mode, Jest compatibility, and out-of-the-box support for TypeScript. In this integration, Cloudflare provides a custom pool that allows your Vitest tests to run inside the Workers runtime.

The Workers Vitest integration:

• Supports both unit tests and integration tests.
• Provides direct access to Workers runtime APIs and bindings.
• Implements isolated per-test storage.
• Runs tests fully-locally using Miniflare ↗.
• Leverages Vitest’s hot-module reloading for near instant reruns.
• Provides a declarative interface for mocking outbound requests.
• Supports projects with multiple Workers.

Get started with one of the available guides:

• Write your first test
• Migrate from Miniflare 2's test environments
• Migrate from unstable_dev

Warning

The Workers Vitest integration does not support testing Workers using the service worker format. Migrate to the ES modules format to use the Workers Vitest integration.