Persistent Rust daemon
jestd parses your config, holds the dependency graph, and keeps the worker pool alive between invocations. The startup tax is paid once per session, not per run.
Features
Everything the daemon buys you
rjest is a small idea executed carefully: move Jest's fixed startup cost into a background daemon, cache the expensive parts on disk, and keep the CLI you already type. Here is the full surface.
Speed
Where the warm-run wins actually come from.
SWC-native transforms
TypeScript and JSX are compiled in Rust by SWC — no Babel, no ts-jest, no plugin chain to reload on every run.
blake3-keyed disk cache
Transformed modules are cached in sled, keyed by blake3 content hash. The cache survives daemon restarts, so a cold restart still reuses prior work.
Warm Node.js worker pool
V8 cold-start is paid once per worker. Tests schedule onto already-JITed processes running in isolated VM contexts.
Compatibility
The whole point is that nothing in your repo changes.
Reads your jest.config
jest.config.js, .ts, .mjs, or the package.json Jest block. No new format, no schema migration.
Same CLI flags
--watch, --coverage, --runInBand, --testNamePattern, --json — the flags your CI script already passes keep working.
Matchers, mocks, snapshots
toBe / toEqual, jest.fn(), jest.mock(), fake timers, and toMatchSnapshot() are honored as compatibility contracts.
Istanbul coverage
--coverage produces Istanbul reports in the formats your dashboards already ingest.
Tooling & agents
Built to be driven by CI and AI coding agents, not just humans.
--json and --machine output
Structured results with file paths, test names, durations, and error details — no ANSI scraping for CI parsers or agents.
Observable daemon
rjest --daemon-status, --daemon-stop, --daemon-restart. Caches persist on disk through restarts, so you can always audit state.
Deterministic watch mode
The daemon FS watcher keeps the dependency graph current, so a save re-runs exactly the affected tests.
Cross-platform binaries
macOS (Intel + Apple Silicon), Linux (x86_64 + aarch64), and Windows (x86_64). Node.js 16 or newer.
See it on your own suite
Read the architecture, browse the guides, or jump to use cases to see where rjest fits.