Vitest

What is it?

Vitest is an open-source unit and integration testing framework created to work natively with Vite. It leverages Vite’s dev server and module graph to deliver extremely fast test runs and modern JavaScript support.

What does it do?

Vitest enables writing and running unit and integration tests with features such as hot module replacement, native ES modules, TypeScript support, snapshot testing, mocking, and code coverage—all with minimal configuration.

Where is it used?

Vitest is widely used in modern frontend applications built with Vite, including Vue, React, Svelte, and Vanilla JS projects. It is especially popular in performance-focused and developer-experience-driven teams.

When & why it emerged

Vitest emerged around 2021 alongside the rise of Vite. It was created to address the performance limitations of traditional test runners in modern ESM-based frontend environments.

Why we use it at Internative

We use Vitest in modern frontend projects where speed, simplicity, and tight integration with Vite are essential. It allows us to run fast feedback loops and maintain high code quality without slowing development.