Dropped Jest support?

[thw0rted]

In #2698, @kettanaito said

MSW has dropped Jest support in 2025

Was this announced somewhere? https://mswjs.io/docs/integrations/node still says

One of the most common uses of MSW in Node.js is with test runners like Jest or Vitest

and to my knowledge there was not a major-version release in 2025.

I get that continuing to evolve MSW while its dependencies are switching to ESM-only makes Jest support complicated, but if you're going to drop support for a runner that still holds a major market share (46M weekly downloads!), that's a breaking change and should only happen as part of the 3.0 release.

[kettanaito]

Hi @thw0rted. Jest+JSDOM support was dropped as early as 2.0 release, I believe. That does not mean MSW doesn't work with those tools. All it means we are not testing against those tools and don't guarantee their support because it stretches way far outside of what MSW should focus on.

This is not a breaking change because MSW doesn't break anything. It's a statement that we are focusing our effort on modern tooling, of which neither Jest nor JSDOM are.

[kettanaito]

There are a ton of people successfully using MSW in Jest (and JSDOM) in 2026. That often requires additional work to achieve because of how outdated those tools are (see https://github.com/mswjs/jest-fixed-jsdom). None of that is exclusive or caused by MSW.