npm/Yarn Package Download Bandwidth

npm Package Download Bandwidth

The npm install command can download hundreds of megabytes of packages, especially for large projects. Understanding these transfer sizes helps with CI/CD planning and developer onboarding.

Typical node_modules Download Sizes

Project Type	Packages	Download Size	Installed Size
Minimal API	50-100	20-50 MB	50-150 MB
React App (CRA)	800-1200	150-250 MB	300-500 MB
Next.js App	500-800	100-200 MB	200-400 MB
Enterprise Monorepo	2000-5000	300-800 MB	1-3 GB

Transfer Time Calculation

Installing a Next.js project (~150 MB download) over different connections:

3G (5 Mbps):     150 * 8 / 5 = 240 seconds = 4 minutes
4G (50 Mbps):    150 * 8 / 50 = 24 seconds
WiFi (100 Mbps): 150 * 8 / 100 = 12 seconds
Fiber (1 Gbps):  150 * 8 / 1000 = 1.2 seconds

npm Registry Performance

The npm registry serves packages from a CDN (Cloudflare):

• Average latency: 50-200 ms per request
• Throughput: Typically 50-200 Mbps per client
• Rate limits: 500 requests per minute (unauthenticated)
• Package tarball download: Limited by CDN and client bandwidth

Reducing Install Bandwidth

1. Package lockfiles: package-lock.json or yarn.lock ensure reproducible installs
2. pnpm: Content-addressable storage saves ~60% disk and network
3. Caching: CI caches save re-downloading unchanged dependencies
4. Verdaccio/Artifactory: Private registry proxy caches packages locally
5. npm ci: Faster than npm install for CI (skips resolution)

Monorepo Considerations

For monorepos with shared dependencies:

Without hoisting: 5 packages * 200 MB = 1 GB total
With hoisting: Shared deps + unique = ~300 MB total
Savings: ~70%

Tools like pnpm, Yarn workspaces, and Turborepo optimize this automatically.