Japa

What Japa is

Japa is a free testing framework for Node.js backend applications and libraries, with support for JSON API and browser testing. It requires Node.js 18 or later and works only with the ES module system. Tests are configured inside an existing Node.js project and run through an entry point using Node.js or Bun rather than a separate CLI. You can arrange tests into suites and groups, use lifecycle hooks and filtering, and run asynchronous or dataset-based cases. Assertion choices include Chai-based assert, Jest-style expect, and TypeScript type assertions. Japa also supports snapshots, pinned tests, bail mode, and coverage reporting through c8 or nyc. Its API client handles JSON, XML, HTML, and plain-text endpoints, while an OpenAPI plugin checks responses against specifications. Browser testing uses a Playwright-based client with browser and context management, built-in assertions, and tracing options. An official VS Code extension runs tests from the editor, and an AdonisJS preset is available.