npm vs Yarn
npm vs Yarn: install speed, lockfile behavior, and whether switching package managers is worth the churn today.
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The short answer
Modern npm (v7+) has closed most of the gap that made Yarn's early speed and determinism advantages compelling, so for most projects sticking with whichever one is already in your lockfile beats migrating. Yarn (via Berry/PnP) still pulls ahead for very large monorepos where install speed and strict dependency resolution matter enough to justify the tooling change.
| Dimension | npm | Yarn |
|---|---|---|
| Comes with Node | Yes, bundled by default | No, separate install |
| Lockfile | package-lock.json | yarn.lock |
| Workspaces/monorepo | Supported since npm 7 | Mature, plus Plug'n'Play mode |
| Install speed | Improved a lot, still slower at huge scale | Fast, especially with PnP/caching |
| Determinism | Lockfile-based, solid since v7 | Lockfile-based; PnP skips node_modules entirely |
Choose npm when
- →You want zero extra setup — npm ships with Node, so there's nothing new to install or for contributors to learn.
- →You're on a small-to-medium project where the historical performance gap with Yarn doesn't actually show up.
- →You want the tool most tutorials, CI templates, and existing answers already assume.
Choose Yarn when
- →You're managing a large monorepo where install time and strict, reproducible dependency resolution genuinely matter.
- →You want Plug'n'Play mode's option to skip node_modules entirely, which can meaningfully speed up CI.
- →Your team already has Yarn-specific tooling or workflows (workspaces, constraints) built around it.
The catch nobody mentions
The gap that once decided this argument — npm having no lockfile at all before v5 — closed years ago, and most 'Yarn is faster and safer' claims online are stale. Switching an existing project's package manager mid-stream is real work (regenerating lockfiles, retraining CI, occasional resolution differences that surface subtly broken behavior), so don't switch without a specific problem the switch would actually fix.