Vitest vs Jest vs Bun Test for Indie Hackers in 2026: Which Should You Use?

If you're picking a test runner for a JavaScript or TypeScript project in 2026, the honest answer is short: use Vitest unless you have a specific reason not to.

Jest ran the show for a decade. It shipped with Create React App, it's baked into NestJS and countless boilerplates, and its ecosystem is still the deepest in the space. But the JavaScript world moved to ES Modules and Vite, and Jest's CommonJS-first roots started to show. Vitest was built for the new world: native ESM, TypeScript with no ts-jest layer, and a watch mode that reruns affected tests in milliseconds. Meanwhile Bun ships its own test runner that beats both on raw execution speed, if you're willing to live inside the Bun runtime.

So the real decision comes down to three questions: what's your stack, how much does watch-mode speed matter, and do you ship to React Native. Here's the breakdown of all three runners, and a clear pick for each situation.

Which test runner is fastest?

Bun Test wins raw execution, Vitest wins the feedback loop, and Jest comes last. On a small suite, Bun's runner can finish in around 0.08 seconds where Jest takes about 1.2 and Vitest about 0.9. But raw start time isn't the number you feel all day. In watch mode, Vitest reruns only the tests affected by a change in tens of milliseconds, while Jest takes seconds. On a large monorepo, published benchmarks put Vitest at roughly 5x faster cold and up to 28x faster on watch reruns than Jest 30, with lower memory. The catch: below about 30 tests, all three feel instant and the difference is academic.

Quick verdict

Vitest: the default for new projects

Vitest, built by Anthony Fu and the Vite team, is the runner most new projects should reach for in 2026. It's on version 4.x, and its whole design is about reusing what Vite already does. If your app has a vite.config.ts, Vitest picks up your aliases, plugins, and resolve conditions automatically, so test configuration is close to zero. TypeScript and JSX compile through esbuild as part of the normal pipeline, with no ts-jest or Babel layer to maintain.

The two things you feel immediately are ESM and watch mode. Vitest treats ES Modules as the default because Vite does, so import.meta, top-level await, and ESM-only packages just work without flags. Its watch mode tracks the module graph the same way Vite's dev server does, so changing one file reruns only the tests that import it, usually in under a second. It also ships coverage (V8 or Istanbul, with HTML reports and CI thresholds), a UI mode, and a stable browser mode that runs tests in real Chromium via Playwright.

The API is intentionally a near-clone of Jest. describe, it, expect, and the lifecycle hooks are identical; you set globals: true and swap jest. for vi..

Who should not use Vitest: React Native teams, since it has no first-class support there. And if you're sitting on a huge Jest suite with custom serializers and deep module mocks, budget for the migration rather than assuming it's free. Vitest's snapshot format differs from Jest's, so you'll regenerate snapshots, and its ecosystem, while strong, is still younger than Jest's decade of plugins.

Jest: still the safe, battle-tested choice

Jest turned eleven in 2025 and shipped Jest 30 that June. It's the most historically referenced test runner in JavaScript, still pulling tens of millions of weekly downloads, and its ecosystem is unmatched: jest-dom, jest-axe, image-snapshot, mature custom serializers, and the deepest pile of Stack Overflow answers and AI training data for debugging obscure issues.

Jest 30 closed real ground. It's meaningfully faster than Jest 29, uses far less peak memory, added native .mts and .cts support, TypeScript config files, and the using keyword for automatic spy cleanup. If you bounced off Jest's ESM story in 2023, it's stabler now.

Where Jest still leads outright is React Native, where it's the only officially supported runner, and large CommonJS monorepos where its behavior is known and its sharding is battle-hardened for suites in the tens of thousands of tests. NestJS and much of the Angular world default to it.

Who should not use Jest: anyone starting a fresh Vite or ESM-first project. Native ESM still often needs the --experimental-vm-modules flag, and mocking an ESM module means jest.unstable_mockModule instead of the clean synchronous call. Cold starts and watch mode are the slowest of the three, especially with ts-jest, and you carry more configuration than Vitest needs. Nothing about Jest is broken, but for a modern greenfield app it's the harder path.

Bun Test: the fastest, if you live in Bun

Bun's built-in test runner, imported from bun:test, is the speed demon. It ships inside the Bun runtime, so there's nothing to install if you already use Bun, and it leans on Bun's native TypeScript transpiler and JavaScriptCore engine to run tests dramatically faster than either rival on pure logic. Its API is Jest-compatible, and it even uses Jest-compatible snapshot serialization, so moving simple Jest tests over is often close to zero code changes.

For a Bun-native project, that's a clean story: one toolchain for your runtime, package manager, and tests, with the fastest feedback loop of the three.

Who should not use Bun Test: most teams with a complex or Node-hosted suite. The gaps are real in 2026. Coverage is experimental, with no HTML reports and branch coverage needing workarounds. Its module mocking is weaker than vi.mock, and complex module mocking often fails. Watch mode reruns every test on any change, with no Vite-style dependency graph. And it only runs in Bun, so your CI has to install Bun, and you're testing in a different runtime than a Node production server, which can surface subtle differences. In real tests it also broke on MSW (no Service Worker API), Prisma mocking, and monorepo workspace imports. It's excellent for utility libraries and backend logic, and risky for DOM-heavy or mocking-heavy suites.

How much configuration does each need?

This is where the daily experience really diverges. On a Vite project, Vitest needs almost nothing:

// vitest.config.ts
import { defineConfig } from 'vitest/config'

export default defineConfig({
  test: {
    globals: true,
    environment: 'jsdom',
    coverage: { provider: 'v8' },
  },
})

Jest, on a TypeScript project, wants more moving parts: a transform, an environment, and usually a module name mapping for path aliases.

// jest.config.js
module.exports = {
  preset: 'ts-jest',
  testEnvironment: 'jsdom',
  moduleNameMapper: {
    '^@/(.*)$': '<rootDir>/src/$1',
  },
}

Bun Test needs no config file at all. You write a test that imports from bun:test and run bun test.

import { describe, it, expect } from 'bun:test'

describe('add', () => {
  it('sums two numbers', () => {
    expect(add(1, 2)).toBe(3)
  })
})

The pattern holds across all three: Bun and Vitest lean on native TypeScript and sensible defaults, while Jest asks you to wire up the transform layer yourself.

What about mocking and coverage?

Two features quietly decide a lot of migrations.

Mocking is where Bun Test still trails. Vitest's vi.mock and Jest's jest.mock are mature and handle module-level mocking, partial mocks, and spies without drama. Bun's mock from bun:test covers the basics but falls over on complex module mocking, which is exactly the kind of thing a real app accumulates over time. If your suite mocks a lot of modules, that alone can rule Bun out.

Coverage tells a similar story. Vitest ships V8 and Istanbul providers with HTML reports and CI thresholds, and Jest's coverage is equally mature. Bun's coverage is still experimental in 2026: fine for a quick percentage, but short on HTML output and branch coverage without workarounds. For a solo founder who just wants a coverage number gating CI, Vitest and Jest are the safer bet.

Head-to-head on what matters

Speed. Bun wins raw execution, sometimes by a wide margin on many small unit tests. Vitest wins the metric you actually live with: watch-mode reruns, thanks to its HMR-style module graph. Jest is the slowest, though switching its transformer to SWC narrows the cold-start gap.

ESM and TypeScript. Vitest and Bun handle both natively with no extra plumbing. Jest 30 improved here but native ESM still leans on a flag, and TypeScript goes through ts-jest, Babel, or SWC. For an ESM-first codebase, this single difference often settles the choice.

Ecosystem. Jest is deepest by a distance. Vitest is close enough that Testing Library, MSW, and the common tools all work well. Bun's plugin ecosystem is the thinnest, and Jest or Vitest plugins don't automatically run under it.

Migration. Jest to Vitest is mostly mechanical: config tweak, jest. to vi., then regenerate snapshots because the format is denser. A small suite is about a day. Jest to Bun preserves snapshots but the mocking gaps bite on anything non-trivial.

flowchart TD
    A[Choosing a test runner in 2026] --> B{React Native project?}
    B -- yes --> C[Jest]
    B -- no --> D{Already all-in on Bun, mostly logic tests?}
    D -- yes --> E[Bun Test]
    D -- no --> F{Large stable Jest suite that works?}
    F -- yes --> G[Stay on Jest 30]
    F -- no --> H[Vitest]

Migrating from Jest to Vitest without drama

If you decide to move, the path is well worn. A rough order that works:

1. Install vitest, plus jsdom or happy-dom for component tests.
2. Add a vitest.config.ts (or extend your existing vite.config.ts) and set globals: true so you don't have to rewrite every import.
3. Run a codemod or find-and-replace to swap jest. calls for vi..
4. Regenerate snapshots with the --update flag, then review every diff, because Vitest's format is denser than Jest's.
5. Fix the stragglers: complex module mocks, fake timers, and any custom transforms.

For a suite under a few thousand tests, this is roughly a day of work. Large monorepos are best done one package at a time, running both runners side by side until each package is green.

The verdict

For most indie hackers starting something new in 2026, Vitest is the pick. It's fast where it counts, it needs almost no config on a modern stack, ESM and TypeScript just work, and because its API mirrors Jest you're not learning a new mental model. The watch-mode speed alone changes the rhythm of how you work.

Stay on Jest when the situation calls for it, and be honest about when it does: React Native, a big stable suite that already works, or deep Jest-specific tooling you don't want to rebuild. Jest 30 is a good tool, not a legacy one, and migrating purely to chase benchmarks is usually a waste of a weekend.

Bun Test is the one to watch. If you've already adopted Bun as your runtime and your tests are mostly pure logic, it's the fastest feedback loop you can get, and using it is consistent with that choice. Just go in knowing the coverage, mocking, and ecosystem gaps, and keep it away from your DOM-heavy and mocking-heavy suites for now.

Once your unit tests are sorted, the next layer is end-to-end. Our Playwright vs Cypress vs Selenium comparison covers that side, and if you're weighing the runtime underneath it all, Bun vs Node vs Deno and pnpm vs npm vs Yarn vs Bun are the natural next reads. For testing your API layer, see our best API testing tools roundup.