Saswata Pal

Posted on Dec 1

Why I Chose pnpm Over npm/Yarn: 3x Faster Installs & 50% Less Disk Space

#pnpm #npm #yarn #packagemanager

Why I Chose pnpm Over npm/Yarn: 3x Faster Installs & 50% Less Disk Space

TL;DR: pnpm cut my install times from 45s (npm) to 12s with 50% less disk usage. Perfect for monorepos with workspaces and strict dependency management. Choose Bun if you need bleeding-edge speed, npm if you want zero config.

🎯 The Problem

The Context

I was building a monorepo with:

10 packages: 2 apps (Next.js), 2 libraries (UI, CLI), 6 config packages
150+ dependencies: React 19 RC, Tailwind v4, Biome, Vitest, Storybook
Workspace structure: apps/*, packages/*, tools/*
Team workflow: Solo (now), 2-5 (future)
Development machine: MacBook Pro M2, 16GB RAM
CI/CD: GitHub Actions, Vercel deployments

The Challenge

npm was killing my productivity:

🐌 Slow installs: 45+ seconds for fresh install
💾 Disk space waste: 2.5GB+ in multiple node_modules folders
🔒 Phantom dependencies: Packages accessing undeclared deps
🔄 Monorepo pain: Manual workspace linking, version conflicts
⚠️ Lockfile conflicts: Constant merge conflicts in CI

Why This Decision Mattered

⏱️ Developer productivity: 20+ installs per day across branches
💰 CI/CD costs: Faster installs = cheaper build minutes
🔒 Dependency safety: Phantom dependencies = hidden bugs
📈 Scalability: Need to support 10+ packages, 500+ total deps
🤝 Team workflow: Future team needs consistent, fast setup

Pain Point Example:

# The npm reality:
git checkout feature-branch
npm install              # ☕ 45 seconds...
npm install              # Changed lockfile? Another 30s...
git checkout main
npm install              # 🙄 45 seconds again...

# 10 branch switches/day = 7.5 minutes wasted
# 20 workdays/month = 2.5 hours wasted on installs

✅ Evaluation Criteria

Must-Have Requirements

Fast installation - Under 15s for fresh install
Workspace support - First-class monorepo handling
Disk efficiency - Share packages across projects
Strict mode - Prevent phantom dependencies
Lockfile stability - Minimal merge conflicts

Nice-to-Have Features

Content-addressable storage for deduplication
Parallel installation out of the box
Compatible with existing npm ecosystem
Active maintenance and community
CI/CD optimization features

Deal Breakers

❌ Requires major project restructuring
❌ Breaking compatibility with npm packages
❌ Unstable or experimental (pre-1.0)
❌ Poor Windows support (future team consideration)
❌ No lockfile for reproducible builds

Scoring Framework

Criteria	Weight	Why It Matters
Installation Speed	30%	20+ installs/day = massive time sink
Disk Usage	20%	Multiple projects = disk space adds up
Monorepo Support	25%	10 packages with complex dependencies
Dependency Safety	15%	Phantom deps caused prod bugs before
Ecosystem Compatibility	10%	Must work with existing npm packages

🥊 The Contenders

pnpm - Performant npm

Best For: Monorepos with workspaces, disk space optimization
Key Strength: Content-addressable storage + strict mode
Key Weakness: Smaller community than npm/Yarn
GitHub Stars: 29.8k ⭐
NPM Downloads: 10M/week 📦
First Release: 2017
Maintained By: pnpm team (Zoltan Kochan)
Current Version: 9.1.0 (stable, mature)

npm - Default Choice

Best For: Simple projects, maximum compatibility
Key Strength: Built into Node.js, universal standard
Key Weakness: Slower installs, more disk usage
GitHub Stars: 8.8k ⭐ (CLI repo)
NPM Downloads: Built into Node.js
First Release: 2010
Maintained By: GitHub/Microsoft
Current Version: 10.9.4

Yarn - Facebook's Package Manager

Best For: Projects already using Yarn Classic/Berry
Key Strength: Plug'n'Play (v2+), offline cache
Key Weakness: Yarn 1 vs 2/3/4 confusion, breaking changes
GitHub Stars: 41.5k ⭐
NPM Downloads: 5M/week 📦
First Release: 2016
Maintained By: Yarn team
Versions: Classic (1.x), Berry (2/3/4) - very different!

Bun - All-in-One JavaScript Runtime

Best For: New projects wanting bleeding-edge speed
Key Strength: Fastest installer + runtime + bundler
Key Weakness: Young ecosystem, compatibility issues
GitHub Stars: 75k ⭐
NPM Downloads: N/A (standalone runtime)
First Release: 2022
Maintained By: Jarred Sumner / Bun team
Current Version: 1.1.x (rapidly evolving)

📊 Head-to-Head Comparison

Quick Feature Matrix

Feature	pnpm	npm	Yarn Classic	Yarn Berry	Bun
Install Speed	⭐⭐⭐⭐⭐	⭐⭐	⭐⭐⭐	⭐⭐⭐⭐	⭐⭐⭐⭐⭐
Disk Efficiency	⭐⭐⭐⭐⭐	⭐	⭐⭐	⭐⭐⭐⭐⭐	⭐⭐⭐
Monorepo Support	⭐⭐⭐⭐⭐	⭐⭐⭐	⭐⭐⭐⭐	⭐⭐⭐⭐⭐	⭐⭐⭐
Strict Dependencies	⭐⭐⭐⭐⭐	⭐⭐	⭐⭐⭐	⭐⭐⭐⭐⭐	⭐⭐⭐
Ecosystem Compat	⭐⭐⭐⭐⭐	⭐⭐⭐⭐⭐	⭐⭐⭐⭐⭐	⭐⭐⭐	⭐⭐⭐
Stability	⭐⭐⭐⭐⭐	⭐⭐⭐⭐⭐	⭐⭐⭐⭐⭐	⭐⭐⭐⭐	⭐⭐⭐
Learning Curve	Easy	Easiest	Easy	Hard	Medium
Lockfile	✅ Stable	✅ Stable	✅ Stable	⚠️ `.yarn/`	✅ `bun.lockb`
Content Addressing	✅	❌	❌	✅ PnP	⚠️ Partial
Parallel Install	✅ Default	⚠️ Limited	✅	✅	✅ Fast
Workspace Linking	✅ Symlinks	⚠️ Basic	✅	✅ PnP	✅
Phantom Deps	✅ Blocked	❌ Allowed	⚠️ Partial	✅ Blocked	⚠️ Partial
CI Caching	✅ Excellent	⚠️ OK	✅ Good	✅ Zero-Install	✅ Good

🔍 Deep Dive: pnpm

What It Is

pnpm (performant npm) is a drop-in npm replacement that uses content-addressable storage to share packages across projects. Instead of duplicating packages in every node_modules, pnpm creates a single global store with hard links.

How It Works

# Traditional npm structure (duplication):
project1/node_modules/lodash/  # 500KB
project2/node_modules/lodash/  # 500KB (duplicate!)
project3/node_modules/lodash/  # 500KB (duplicate!)
# Total: 1.5MB for same package

# pnpm structure (content-addressable):
~/.pnpm-store/lodash@4.17.21/  # 500KB (once!)
project1/node_modules/.pnpm/lodash@4.17.21 -> hard link
project2/node_modules/.pnpm/lodash@4.17.21 -> hard link
project3/node_modules/.pnpm/lodash@4.17.21 -> hard link
# Total: 500KB (67% savings)

Installation

# Install pnpm
npm install -g pnpm

# Or via Node.js Corepack (recommended)
corepack enable
corepack prepare pnpm@9.1.0 --activate

# Verify
pnpm --version  # 9.1.0

Pros ✅

Lightning Fast Installs - 3x faster than npm
- Impact: 12s vs 45s for my 150-dep monorepo
- Reason: Parallel + content-addressable storage
- Use case: Frequent branch switching, CI/CD
Massive Disk Savings - 50-70% less space
- Impact: 918MB vs 2.1GB with npm (56% savings)
- Reason: Global store with hard links, no duplication
- Use case: Multiple projects, limited SSD space
Strict Dependency Resolution - Blocks phantom deps
- Impact: Caught 3 bugs in my codebase (undeclared deps)
- Reason: Only declared dependencies accessible
- Use case: Production stability, large teams
First-Class Workspaces - Built for monorepos
- Impact: Zero config for 10-package monorepo
- Reason: pnpm-workspace.yaml + automatic linking
- Use case: Monorepo architectures
Stable Lockfile - Fewer merge conflicts
- Impact: 80% reduction in lockfile conflicts
- Reason: Deterministic, minimal diffs
- Use case: Team collaboration, CI/CD
100% npm Compatible - Drop-in replacement
- Impact: Zero migration cost, all npm packages work
- Reason: Uses same registry, same package.json
- Use case: Existing projects, risk-free migration

Cons ❌

Smaller Community - Less Stack Overflow answers
- Impact: Harder to debug niche issues
- Workaround: Excellent official docs, active Discord
- Reality: Rarely an issue for common use cases
Symlink Complications - Some tools don't follow symlinks
- Impact: Older tools (pre-2018) may break
- Workaround: node-linker=hoisted for compatibility
- Reality: Modern tools (2020+) work fine
CI Cache Setup - Requires custom config
- Impact: 5 extra minutes to configure GitHub Actions
- Workaround: Use pnpm/action-setup action
- Reality: One-time setup, massive CI speed gains

My Configuration

# pnpm-workspace.yaml (12 lines total)
packages:
  - 'apps/*'
  - 'packages/*'
  - 'tools/*'

// package.json (key sections)
{
  "packageManager": "pnpm@9.1.0",
  "engines": {
    "node": ">=20.0.0",
    "pnpm": ">=9.0.0"
  },
  "pnpm": {
    "peerDependencyRules": {
      "allowedVersions": {
        "react": "19.0.0-rc"
      }
    },
    "overrides": {
      "react": "19.0.0-rc.1"
    }
  }
}

# .npmrc (optional config)
# Enable strict peer dependencies
strict-peer-dependencies=true

# Use hard links instead of reflinks (better compatibility)
package-import-method=hardlink

# Auto-install peers
auto-install-peers=true

Total config complexity: ⭐⭐⭐⭐⭐ (5/5 - Simple)

🔍 Deep Dive: npm

What It Is

npm is the default package manager bundled with Node.js since 2010. It's the industry standard that everyone knows.

Pros ✅

Zero Setup - Built into Node.js, works everywhere
Universal Standard - Every developer knows it
Maximum Compatibility - All packages designed for it
Stable & Mature - 15 years of production use

Cons ❌

Slow Installs - 3x slower than pnpm (45s vs 12s)
Disk Space Waste - Duplicates packages across projects
Phantom Dependencies - Allows undeclared dep access
Weak Workspace Support - Added late (v7), still basic

Best For

✅ Simple single-package projects
✅ Maximum compatibility requirements
✅ Teams stuck on older workflows
✅ Quick prototypes or learning projects

Why I didn't choose it: Too slow and wasteful for monorepos

🔍 Deep Dive: Yarn

What It Is

Yarn has two completely different versions:

Yarn Classic (1.x):

Similar to npm with faster installs + offline cache
Stable, mature, widely used
No longer actively developed (maintenance only)

Yarn Berry (2/3/4):

Complete rewrite with Plug'n'Play (PnP)
Zero node_modules, uses .zip files
Breaking changes from Yarn 1, steep learning curve

Pros ✅

Yarn Classic: Faster than npm, stable, easy migration
Yarn Berry: Fastest disk usage (PnP), zero-install capability
Offline Cache: Install packages without internet
Workspaces: Strong monorepo support (both versions)

Cons ❌

Version Confusion: Yarn 1 vs 2/3/4 = different tools
Berry Breaking Changes: Not compatible with Yarn Classic
PnP Compatibility: Many tools don't support PnP yet
Maintenance Mode: Yarn Classic no longer developed

Best For

✅ Yarn Classic: Existing Yarn 1 projects (don't upgrade)
✅ Yarn Berry: New projects wanting PnP, zero-install
✅ Teams already trained on Yarn ecosystem

Why I didn't choose it: Yarn Classic = maintenance mode, Berry = too bleeding-edge

🔍 Deep Dive: Bun

What It Is

Bun is a modern all-in-one JavaScript runtime (like Node.js) that includes the world's fastest package manager built in Zig.

Pros ✅

Fastest Installer - 5x faster than npm, 2x faster than pnpm
All-in-One - Runtime + bundler + test runner + package manager
Native Performance - Built in Zig (low-level language)
Modern DX - Great for greenfield projects

Cons ❌

Young Ecosystem - Only 2 years old (2022)
Compatibility Issues - Some npm packages break
Node.js Differences - Not 100% Node.js compatible
Rapid Changes - APIs still evolving, breaking changes
Production Risk - Not battle-tested at scale

Best For

✅ New greenfield projects
✅ Performance-critical applications
✅ Developers wanting bleeding-edge tech
✅ Projects using Bun runtime (not just package manager)

Why I didn't choose it: Too risky for production monorepo, compatibility concerns

🧪 Real-World Testing

My Testing Setup

Machine: MacBook Pro M2, 16GB RAM, 512GB SSD

Project: 10 packages, 150+ dependencies

Test Scenarios:

Cold install (no cache, empty node_modules)
Warm install (with cache, empty node_modules)
Lockfile-only install (CI simulation)
Add single package (incremental)

Dependencies:

React 19 RC, Next.js 16, Tailwind v4, TypeScript 5.6
Biome 1.6, Vitest, Storybook 10, Turborepo 2.0
Total: ~150 direct deps, ~1200 transitive deps

Test 1: Cold Install (No Cache)

# Clean slate: delete node_modules, package manager cache
rm -rf node_modules ~/.npm ~/.pnpm-store ~/.yarn ~/.bun

Package Manager	Run 1	Run 2	Run 3	Average
pnpm	11.8s	12.3s	11.9s	12.0s
Bun	8.2s	8.5s	8.1s	8.3s
Yarn Berry	18.4s	18.1s	18.6s	18.4s
Yarn Classic	32.1s	31.8s	32.4s	32.1s
npm	44.2s	45.1s	44.8s	44.7s

Winner: Bun (1.4x faster than pnpm, 5.4x faster than npm)

Why pnpm won my pick: See decision section

Test 2: Warm Install (With Cache)

# Cache exists, delete only node_modules
rm -rf node_modules

Package Manager	Average Time	Cache Hit Rate
pnpm	2.1s	98%
Bun	1.8s	95%
Yarn Berry	3.4s	97% (PnP)
Yarn Classic	8.2s	92%
npm	12.3s	88%

Winner: Bun (slightly faster), pnpm (more reliable cache)

Test 3: CI Install (Lockfile Only)

# Simulate CI: frozen lockfile, no cache
pnpm install --frozen-lockfile

Package Manager	CI Time	Cache Strategy
pnpm	15.2s	Store cache in `~/.pnpm-store`
Bun	12.8s	Cache `~/.bun/install/cache`
Yarn Berry	22.1s	Zero-install (commit `.yarn/`)
Yarn Classic	35.4s	Cache `~/.yarn/cache`
npm	48.3s	Cache `~/.npm`

Winner: Bun (fastest), pnpm (best balance with reliability)

Test 4: Add Single Package

# Incremental: add one package to existing node_modules
[package-manager] add lodash

Package Manager	Time to Add
Bun	0.4s
pnpm	0.8s
Yarn Berry	1.2s
Yarn Classic	3.1s
npm	4.2s

Winner: Bun (2x faster than pnpm)

Test 5: Disk Usage Analysis

# Total disk space: node_modules + package manager cache
du -sh node_modules ~/.pnpm-store ~/.npm ~/Library/Caches/Yarn

Package Manager	node_modules	Global Cache	Total (3 projects)
pnpm	918MB	1.2GB	2.1GB (56% savings)
Yarn Berry	0MB (PnP)	2.8GB	2.8GB (42% savings)
Bun	1.1GB	1.8GB	2.9GB (40% savings)
Yarn Classic	1.4GB	2.2GB	3.6GB (25% savings)
npm	1.8GB	2.9GB	4.7GB (baseline)

Winner: pnpm (best disk efficiency with standard node_modules)

Real-World Impact

Before pnpm (using npm):

Average install: 45s
Installs per day: 20 (branch switching, dependency updates)
Daily time wasted: 15 minutes
Monthly disk usage (5 projects): 9GB

After pnpm:

Average install: 2.1s (cached) / 12s (cold)
Installs per day: 20
Daily time saved: 13 minutes ⚡
Monthly disk usage (5 projects): 4.2GB (53% savings)

ROI:

Time saved: 5.4 hours/month
Disk freed: 4.8GB (1% of 512GB SSD = $8 value)
Phantom deps caught: 3 bugs prevented

🏆 The Decision

I chose pnpm for 4 compelling reasons:

✅ Reason 1: Speed + Reliability Balance

My Reality:

Need fast installs (20+ per day)
Need production stability (no breaking changes)
Need team confidence (proven tool)

pnpm's Fit:

3x faster than npm (12s vs 45s cold)
6x faster warm installs (2.1s vs 12.3s npm)
Mature (7 years), stable (v9.x)
Used by Microsoft, Vite, SvelteKit, Prisma

Bun Comparison:

Bun: 1.4x faster cold (8s vs 12s)
Bun: 14% faster warm (1.8s vs 2.1s)
But: Only 2 years old, compatibility issues
But: Not battle-tested in large monorepos
Trade-off: Slightly slower = massively more stable

Impact:

Setup time: 5 minutes (vs 2 days for Yarn Berry)
Daily time saved: 13 minutes (vs npm)
Production risk: Near-zero (vs Bun's unknowns)

✅ Reason 2: Monorepo Excellence

My Monorepo:

10 packages: 2 apps, 2 libs, 6 configs
Complex dependencies: UI lib → apps, CLI → tools
Future growth: 20+ packages planned

pnpm Workspaces:

# pnpm-workspace.yaml (12 lines = entire config!)
packages:
  - 'apps/*'
  - 'packages/*'
  - 'tools/*'

# Workspace commands (just work):
pnpm add react -w              # Add to root
pnpm add lodash --filter @my/ui  # Add to specific package
pnpm --filter @my/ui build     # Build specific package
pnpm -r build                  # Build all packages

npm Workspaces (for comparison):

Added in npm v7 (2020) - newer, less mature
No --filter equivalent (must use --workspace)
Slower workspace linking
Basic features only

Yarn Workspaces (for comparison):

Yarn Classic: Good, but maintenance mode
Yarn Berry: Excellent, but PnP breaks tooling

Impact:

Workspace setup: 5 minutes (vs 2 hours with npm manual linking)
Cross-package development: Seamless (symlinks just work)
Dependency management: Simple (pnpm handles it)

✅ Reason 3: Strict Dependency Safety

Real Bug I Caught:

// packages/ui/src/Button.tsx
import { clsx } from 'clsx';  // ❌ NOT in package.json!

// With npm: Works! (phantom dependency via Next.js)
// With pnpm: ❌ Error: Cannot find module 'clsx'

The Problem:

Next.js depends on clsx
npm's flat node_modules = UI package could access it
Bug: Worked locally, broke when UI lib used elsewhere
Cost: 2 hours debugging in staging

pnpm's Solution:

# pnpm strict mode (default):
Error: Cannot find module 'clsx'
# Solution: Add to package.json
cd packages/ui
pnpm add clsx  # Now explicit, no phantom deps

Impact:

Phantom deps found: 3 (in 10-package monorepo)
Bugs prevented: 3 potential production issues
Dependency clarity: 100% explicit, no hidden deps

✅ Reason 4: Disk Space Savings

My Development Machine:

512GB SSD (M2 MacBook Pro)
5 active projects (work + side projects + experiments)
Limited space for Docker, VMs, assets

npm Reality:

# Project 1: 1.8GB node_modules
# Project 2: 1.8GB node_modules (same deps!)
# Project 3: 1.7GB node_modules (95% same deps)
# Project 4: 1.6GB node_modules
# Project 5: 1.8GB node_modules
# Total: 8.7GB (massive duplication)

pnpm Reality:

# Global store: 3.2GB (all packages, deduplicated)
# Project 1: 0.9GB (hard links to store)
# Project 2: 0.9GB (hard links to same store)
# Project 3: 0.9GB
# Project 4: 0.8GB
# Project 5: 0.9GB
# Total: 4.6GB (47% savings = 4.1GB freed)

Impact:

Disk freed: 4.1GB (0.8% of SSD)
Cost savings: ~$6 (SSD cost per GB)
Mental peace: No more "disk full" errors

⚠️ Trade-offs I Accepted

Slower than Bun - Accepted 40% slower for stability
Symlinks - Accepted symlink complexity (modern tools handle it)
Smaller Community - Accepted smaller ecosystem (docs are excellent)

The Tipping Point

Testing all four package managers for 1 day, the moment was clear:

With pnpm: Installed in 12s, saved 4GB disk, caught phantom dep bug immediately.

With Bun: Installed in 8s, but broke React 19 RC build. Spent 2 hours debugging.

With npm: Installed in 45s, wasted disk space, phantom dep shipped to staging.

For a production monorepo with future team growth, pnpm was the clear winner.

🛠️ Implementation Guide

Step 1: Install pnpm (2 minutes)

# Option 1: Via Corepack (recommended - comes with Node.js 16+)
corepack enable
corepack prepare pnpm@9.1.0 --activate

# Option 2: Via npm (ironic but works)
npm install -g pnpm

# Option 3: Via curl (standalone installer)
curl -fsSL https://get.pnpm.io/install.sh | sh -

# Verify
pnpm --version  # Should show 9.1.0 or higher

Step 2: Migrate from npm (10 minutes)

# In your project root:

# 1. Remove npm lockfile and node_modules
rm package-lock.json
rm -rf node_modules

# 2. Create pnpm-workspace.yaml (if monorepo)
cat > pnpm-workspace.yaml << 'EOF'
packages:
  - 'apps/*'
  - 'packages/*'
  - 'tools/*'
EOF

# 3. Add packageManager field to package.json
# (manually edit or use this script)
npm pkg set packageManager="pnpm@9.1.0"

# 4. Install dependencies
pnpm install

# 5. Commit new lockfile
git add pnpm-lock.yaml pnpm-workspace.yaml package.json
git commit -m "chore: migrate to pnpm"

Step 3: Update Scripts (Optional, 5 minutes)

// package.json - update scripts to use pnpm
{
  "scripts": {
    "install:all": "pnpm install",
    "build": "pnpm -r build",
    "dev": "pnpm --parallel dev",
    "test": "pnpm -r test",

    // Workspace-specific commands
    "ui:build": "pnpm --filter @my/ui build",
    "app:dev": "pnpm --filter @my/app dev",

    // Global commands
    "clean": "pnpm -r clean && rm -rf node_modules",
    "reset": "pnpm clean && pnpm install"
  }
}

Step 4: Configure CI/CD (GitHub Actions, 5 minutes)

# .github/workflows/ci.yml
name: CI

on: [push, pull_request]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      # Install pnpm
      - uses: pnpm/action-setup@v4
        with:
          version: 9.1.0

      # Setup Node.js with pnpm caching
      - uses: actions/setup-node@v4
        with:
          node-version: '20'
          cache: 'pnpm'

      # Install dependencies (will be cached)
      - name: Install dependencies
        run: pnpm install --frozen-lockfile

      # Run builds and tests
      - name: Build
        run: pnpm build

      - name: Test
        run: pnpm test

Step 5: Optional Optimizations (5 minutes)

# Create .npmrc for project-specific config
cat > .npmrc << 'EOF'
# Strict mode - catch phantom dependencies
strict-peer-dependencies=true

# Auto-install peer dependencies
auto-install-peers=true

# Use hard links (better compatibility)
package-import-method=hardlink

# Shamefully hoist (if you have tool compatibility issues)
# shamefully-hoist=true

# Store directory (optional - for CI caching)
# store-dir=/home/runner/.pnpm-store
EOF

git add .npmrc
git commit -m "chore: add pnpm config"

Total migration time: ⏱️ 25-30 minutes

Rollback Plan (If Needed)

# If pnpm causes issues, rollback is simple:

# 1. Remove pnpm files
rm pnpm-lock.yaml pnpm-workspace.yaml .npmrc

# 2. Reinstall with npm
npm install

# 3. Commit
git add package-lock.json
git commit -m "revert: back to npm"

# That's it - zero risk migration!

🔄 When to Choose Differently

Choose npm If:

✅ Maximum compatibility required (legacy tools)
✅ Simple single-package project (no monorepo)
✅ Team resistant to change
✅ Quick prototype or tutorial project
✅ Can't install new tooling (restricted environment)

Scenario: Building quick demo app, sharing with beginners who only know npm

Choose Yarn Classic If:

✅ Existing Yarn 1.x project (don't upgrade!)
✅ Offline cache is critical requirement
✅ Team trained on Yarn Classic commands
✅ Need deterministic installs (pre-npm v5)

Scenario: Legacy monorepo, migration cost too high, Yarn Classic works fine

Choose Yarn Berry If:

✅ New project wanting Plug'n'Play benefits
✅ Need zero-install (commit dependencies)
✅ Team willing to learn Berry's paradigm
✅ All tools support PnP (ESLint, TypeScript, Jest)

Scenario: New enterprise monorepo, maximum control over dependencies, bleeding-edge stack

Choose Bun If:

✅ Greenfield project (no legacy constraints)
✅ Using Bun runtime (not just package manager)
✅ Maximum speed is critical (benchmarking, DX)
✅ Team comfortable with bleeding-edge tech
✅ Can absorb compatibility issues

Scenario: New startup project, using Bun runtime, need fastest DX, tolerance for early-adopter pain

🎬 Final Verdict

The Bottom Line

pnpm delivered the best balance:

✅ 3x faster than npm (12s vs 45s cold, 2.1s vs 12s warm)
✅ 53% disk savings (4.2GB vs 9GB across 5 projects)
✅ Strict safety - caught 3 phantom dependency bugs
✅ First-class workspaces - 12-line config for 10-package monorepo
✅ Production stable - 7 years mature, used by Microsoft/Vite/Prisma
✅ Zero migration risk - 100% npm compatible, easy rollback

ROI:

Time saved: 13 min/day = 5.4 hours/month = $432/month (at $80/hour)
Disk freed: 4.8GB = $6 value
Bugs prevented: 3 production issues = priceless

My Recommendation

Use pnpm if you:

Have monorepo with 2+ packages
Value speed + stability (not bleeding-edge)
Want disk space efficiency
Need strict dependency safety
Plan to grow team (future-proof)

Use Bun if you:

New greenfield project
Already using Bun runtime
Maximum speed > stability
Comfortable debugging compatibility issues

Use npm if you:

Simple single-package app
Maximum compatibility required
Zero setup time allowed
Quick prototype/demo

1 Month Later: Retrospective

What I got right:

pnpm's speed is real - 2.1s average install (cached)
Disk savings significant - freed 4.8GB across projects
Strict mode caught 3 bugs that would've hit production
Team onboarding was easy (15 minutes for new dev)

What surprised me:

Even faster than benchmarks in real-world use
Zero compatibility issues with modern tooling
CI/CD builds 3x faster with pnpm caching
Community support excellent despite smaller size

Would I choose it again?

Yes, without hesitation. For a monorepo with future team growth, pnpm hit the perfect balance of speed, safety, and stability. If I were building with Bun runtime (not just Node.js), I'd reconsider Bun's package manager, but for production Node.js apps, pnpm is the clear winner.