Vitest

Testing framework powered by @vite_js ⚡️, brought to you by @voidzerodev | Bluesky: 🦋

[Vitest @vitest_dev]

Vitest 4 is out!

- Browser Mode is Stable
- Visual Regression Testing
- Improved Debugging
- Pool Stabilization
- New APIs
- Bug Fixes

Stay updated with our blog post:

https://t.co/b7iNEO4uLB

[Alexander Lichter @TheAlexLichter]

Are you in Amsterdam (or NL) this Thursday?

Then you should join our @vitest_dev x npmx meetup!

https://t.co/vuXaUpTy3D

See y’all there! 👀

[VoidZero @voidzerodev]

🚀 @vitest_dev 5.0.1 is out with more than 18 fixes

Among them: `define` values are no longer double-quoted in browser mode!

It also includes a focused Trace View layout which is used by the Vitest VS Code extension.

Time to update 👀

https://t.co/hZibOyT4pf

[VoidZero @voidzerodev]

VoidZero is joining Cloudflare.

Our mission stays the same: to make JavaScript developers more productive than ever before. Vite, Vitest, Rolldown, Oxc, and Vite+ remain MIT-licensed. Evan and the VoidZero team will continue leading them.

Cloudflare shares our commitment to open source. Together, we can keep investing in the tooling developers rely on every day, while bringing the Vite ecosystem and Cloudflare’s platform even closer together.

[Vitest @vitest_dev]

https://t.co/4mp74DNb5q

[Vitest @vitest_dev]

We've published a Browser Mode security advisory.

CDP-capable providers like Playwright Chromium with the browser API exposed to the network allowed attackers to run code on the host.

Update vitest/browser to 5.0.0-beta.4, 4.1.8, or 3.2.6.
Vite+ users: Upgrade to 0.1.24

[Chromatic @chromaticcom]

We’re launching early access for Vitest visual testing with Chromatic! ⚡️

Built with @vitest_dev core maintainer Ari Perkkio, Chromatic adds visual testing to the browser tests you already write. 🧵 (1/4)

[Vitest @vitest_dev]

https://t.co/VzeMsT7EeN

[Vitest @vitest_dev]

🚨 We are publishing Vitest 4.1.6 and Vitest 5.0.0-beta.3 to resolve recent vulnerabilities:

- `--api` and `--ui` exposed arbitrary files to the network
- `--api` allowed arbitrary execution
- `?otelCarrier` XSS

More information on our GitHub security page

[Vitest @vitest_dev]

Read our announcement post for all the details
https://t.co/TDLIfpCj5p

[Vitest @vitest_dev]

Vitest 4.1 is out! 🚀

✅ Vite 8 support from day 1
🏷️ Test tags to organize, filter & apply shared options
🪝 New hooks for easier tracing, transactions and AsyncLocalStorage
🔍 Async leak detection
🤖 Agent reporter to reduce token usage

And much more!

[Vitest @vitest_dev]

@mhsnook @tannerlinsley @ashishxcode @tan_stack

[Boris Cherny @bcherny]

In the next version of Claude Code..

We're introducing two new Skills: /simplify and /batch. I have been using both daily, and am excited to share them with everyone.

Combined, these kills automate much of the work it used to take to (1) shepherd a pull request to production and (2) perform straightforward, parallelizable code migrations.

[VoidZero @voidzerodev]

Flaky tests and memory leaks are the worst.

@vitest_dev now has a --detect-async-leaks flag that catches uncleared intervals, lingering servers, and other async operations leaking across your tests.

⚠️ Don't run it on every run though. Use it to audit your test suite, then clean things up.

Available in the latest 4.1 beta. Big shout out to Ari from the Vitest team for landing this PR! 🔥

[VoidZero @voidzerodev]

Tests.

Vitest's browser mode is stable since Vitest 4.0.
Now you can be sure that your tests pass in an *actual* browser environment.

https://t.co/3YxidTNQsm

[VoidZero @voidzerodev]

✨ What's New in ViteLand: January 2026 Recap

◆ Unified redesign across all VoidZero sites
◆ @vite_js crossed 3 billion npm downloads
◆ @rolldown_rs reached RC status
◆ Lazy Barrel Optimization landed in Rolldown
◆ Oxfmt hit 100% Prettier conformance
◆ Oxlint gets a dynamic .ts config
◆ ...and much more 👀

Full recap below!

[VoidZero @voidzerodev]

The first beta for @vitest_dev 4.1 is out! 🧪

What's new:
◆ Chai-style spy assertions (`toHaveBeenCalled`, etc.)
◆ `userEvent.wheel()` for browser mode
◆ Enhanced retry options for flaky tests
◆ Disposable returned from `doMock()`
◆ Respecting coverage ignore start/stop hints
◆ and more 👀

Try now by installing vitest@beta

[VoidZero @voidzerodev]

New Year. New Look. Same Mission.

Make JavaScript developers more productive than ever before

[VoidZero @voidzerodev]

Want to speed up subsequent @vitest_dev runs?
Then try out the new experimental file-system based cache ✨

⋄ Caches transformed modules
⋄ Does *not* work with browser mode yet
⋄ Can be manually cleared via `vitest --clearCache`

More in the docs
https://t.co/IpfjVpJmbG

[Chris Cook @zirkelc]

I started a proof of concept to integrate the standard schema natively into @vitest_dev

It's currently being discussed integrating this directly into `toEqual()`, creating a new custom matcher like `toEqualSchema()` or an asymmetric matcher like `schemaMatching()`