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Vitest vs Jest vs Bun Test (2026): JavaScript Test Runner Comparison

The JavaScript test runner landscape has transformed since 2024. Vitest (Vite-native, Jest-compatible) has overtaken Jest in new projects, and Bun Test offers blazing-fast execution by leveraging Bun's JavaScript engine. Each has a distinct philosophy: Jest prioritizes stability and ecosystem, Vitest prioritizes speed and Vite integration, and Bun Test prioritizes raw performance.

Quick Comparison

Feature Jest Vitest Bun Test

Runtime Node.js (vm or worker_threads) Vite dev server (Node.js) Bun runtime (JavaScriptCore)

Speed (1,000 simple tests) ~8 seconds ~2 seconds (with --pool=forks) ~0.8 seconds

Jest API Compatibility Native Near-complete (expect, describe, it, mock) Partial (describe, it, expect with jest-matcher-like API)

Watch Mode Yes (--watch) Yes (--watch, faster via Vite…