Why npm Is Slow on VPN

The npm registry (registry.npmjs.org) uses a global CDN optimized for fast downloads. But when you're on VPN, every request takes a detour through your corporate server first.

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  Added latency per request

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  Bandwidth throttling on VPN connection

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  Hundreds of packages = hundreds of slow requests

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  Each small package multiplies the overhead

How Slow Are We Talking?

The difference is dramatic:

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  Normal npm install: 30 seconds

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  On VPN: 5-10 minutes (or more)

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  Large projects with deep node_modules: Even worse

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  Fresh installs after clearing cache: Painful

Quick Test

# Time an install off VPN
time npm install lodash

# Connect VPN, clear cache
npm cache clean --force

# Time again
time npm install lodash

Compare the times. The VPN overhead becomes obvious.

Fix 1: Use npm Cache

# Prefer offline packages when available
npm install --prefer-offline

This helps for repeat installs of the same packages. But your first install is still slow.

Fix 2: Use yarn or pnpm

These package managers have better caching and parallel downloads:

# pnpm is especially fast
npm install -g pnpm
pnpm install

Still affected by VPN, but the parallelization helps.

Fix 3: Route Terminal Direct (Best)

The most effective fix: route your Terminal outside the VPN tunnel.

Other Package Managers That Benefit

Route Terminal direct and all these speed up:

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  npm / yarn / pnpm (Node.js)

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  pip (Python)

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  gem (Ruby)

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  cargo (Rust)

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  go get (Go)

• •

  composer (PHP)

Any package manager downloading from public registries benefits from direct routing.

Private npm Registries

If your company uses a private npm registry that requires VPN access, you have options:

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  Keep Terminal on VPN when installing private packages

• •

  Route Terminal direct for public package installs

• •

  Switch routing based on what you're working on

SplitTunnel makes it easy to toggle Terminal's routing as needed.

Verifying the Speed Improvement

After setting up SplitTunnel with Terminal routed direct:

# Clear cache for clean test
npm cache clean --force

# Connect VPN

# Time a fresh install
time npm install express

# Should match non-VPN speeds