Pnpm: Faster, Leaner Node.js Package Manager - Save Disk

If you’re still installing dependencies with Npm or Yarn, you might be donating minutes and gigabytes you’ll never get back. I switched one noisy repo to Pnpm (pnpm) and my laptop fan basically retired on the spot. It speeds up installs and skips duplicating the same packages across projects, without making you relearn your whole workflow.

Why developers are switching to Pnpm

• Speed that scales: Often clearly faster on fresh installs and in CI, and the gap widens as repos grow.
• Huge disk savings: Instead of duplicating the same library in every node_modules, pnpm reuses a single copy across projects.
• Fewer surprises: A stricter, more accurate dependency layout helps prevent “it works on my machine” mysteries.
• Great for monorepos: First-class workspace support keeps multi-package projects tidy and consistent.

According to the official Motivation page, pnpm stores packages in a global, content‑addressable store and links them into each project. That’s why disk usage drops and installs get faster as you add more projects on the same machine.

How Pnpm works (in plain English)

Traditional managers copy dependencies into every project’s node_modules. Pnpm instead:

1. Downloads a package version once into a global content-addressable store on your machine.
2. Adds hard links/symlinks from your project’s node_modules back to that store.
3. Builds a non-flat, accurate dependency tree (you’ll notice a virtual store under node_modules/.pnpm) that mirrors how packages actually depend on each other.

The result: less disk I/O, less duplication, and cleaner isolation between direct and transitive dependencies. Think fewer “where did that dependency come from?” moments.

Real-world performance: what to expect

While results vary by project and CI setup, tests from large monorepos show a clear pattern:

• Yarn 2: around 6.5 minutes on a cold cache; about 1.2 minutes warm
• Yarn 3 (tuned): around 1.2 minutes cold; ~45 seconds warm
• Pnpm: around 58 seconds cold; ~24 seconds warm

These numbers are from one detailed case study; your mileage will vary. Still, the trend holds: pnpm shines during cache misses and stays snappy with a warm cache.

Pnpm vs Npm vs Yarn: quick comparison

Category	Pnpm	Npm	Yarn
Install speed	Very fast (cold and warm)	Solid, but slower on large graphs	Fast; Yarn 3 can be very competitive
Disk usage	Minimal duplicates via global store + links	Duplicates per project	Duplicates per project (unless using advanced modes)
node_modules layout	Nested, accurate; virtual store under .pnpm	Flat hoisted	Flat hoisted by default
Dependency isolation	Strict, avoids phantom deps	Can allow undeclared access via hoisting	Can allow undeclared access via hoisting
Workspaces/monorepos	Built-in and ergonomic	Supported	Supported, powerful
Learning curve	Light; new layout/commands	Very familiar	Familiar; advanced features add complexity

Getting started with Pnpm (5 steps)

1) Install pnpm globally

• Using Npm: npm install -g pnpm
• Or via Corepack (Node 16.13+): corepack enable && corepack prepare pnpm@latest --activate

2) Clean the project

• Remove prior artifacts: rm -rf node_modules package-lock.json yarn.lock

3) Import lockfile (optional)

• From npm or yarn: pnpm import

4) Install deps

• pnpm install

5) Update scripts and docs

• Replace commands like npm run with pnpm run where appropriate.
• In monorepos, create a pnpm-workspace.yaml with your package globs.

Pro tip: Use one package manager per project. Commit pnpm-lock.yaml and document the choice for your team.

Common migration pitfalls (and fixes)

• Undeclared dependencies break builds

  • Why it happens: pnpm’s strict layout blocks access to packages you didn’t declare.
  • Fix: add the missing dependency explicitly, or (as a last resort) use hoisting options like public-hoist-pattern/shamefully-hoist for tools that expect a flat layout.

• Tools that don’t follow symlinks well

  • Some build tools or CLIs assume a flat node_modules. Add the exact dependency to the workspace using it, or enable limited hoisting for that package.

• CI caching feels “off”

  • Ensure you cache pnpm’s global store directory and pnpm-store paths. Always restore cache before pnpm install.

• Team muscle memory

  • Create a local alias, e.g., alias pn=pnpm, and share a short command map (see below) in your README.

Command cheat sheet (Npm/Yarn → Pnpm)

• Install all: npm install / yarn install → pnpm install
• Add a prod dep: npm i lodash / yarn add lodash → pnpm add lodash
• Add a dev dep: npm i -D typescript / yarn add -D typescript → pnpm add -D typescript
• Remove: npm uninstall pkg / yarn remove pkg → pnpm remove pkg
• Update: npm update / yarn upgrade → pnpm update
• Run script: npm run build / yarn build → pnpm run build
• Workspaces: npm -w pkg run test / yarn workspace pkg test → pnpm -F pkg run test

Best practices for smooth adoption

• Standardize on pnpm per repo; don’t mix managers.
• Commit pnpm-lock.yaml and review it in PRs.
• Keep Node and pnpm up to date across dev machines and CI.
• In monorepos, define clear workspace globs and use pnpm -r for repo-wide commands.
• Cache the pnpm store in CI and restore it early in the pipeline.

Should you use Pnpm?

Choose the right tool for your context:

• Pick Pnpm if you manage large projects or monorepos, want faster fresh installs, or have limited disk space.
• Stick with Npm for maximum compatibility and if your project is small and simple.
• Consider Yarn if your team already standardizes on it and benefits from its specific features.

For many teams, a quick trial is enough: convert one repo, measure install times (cold and warm), and check disk usage. If the results mirror what others report, faster installs and smaller footprints, roll Pnpm out more widely.

Conclusion

Pnpm delivers faster installs, strict and reliable dependency resolution, and real disk-space savings. If you juggle multiple projects or a monorepo, it’s one of the easiest wins you can land this quarter. Try Pnpm on a single repository, measure the difference, and see if it earns a permanent spot in your toolkit.