Jest is a JavaScript testing framework with a focus on simplicity. It works with projects using Babel, TypeScript, Node, React, Angular and Vue, and offers zero-config setup, snapshot testing, parallel test execution, built-in code coverage and easy mocking. Jest is open-source software under the MIT licence and runs locally or in your own CI environment; no vendor cloud service is needed.
Jest originated at Facebook (now Meta). In May 2022 Meta transferred the project to the OpenJS Foundation, which provides its organisational home, while the Jest Core team manages it. The foundation is based in the United States, and the project has since been designated an at-large project of the foundation. Because the source code is public and tests run on your own infrastructure, there is no dependence on a particular cloud provider. A European organisation can run Jest itself and inspect the code.