Difference Between npm Global and Local Install

When working with Node.js, understanding how to manage package dependencies is crucial for maintaining a clean and efficient development environment. This article explains the key differences between global and local npm installations, detailing where packages are stored, how they are accessed, and when to use each method to optimize your workflow.

Local Installation

A local installation is the default behavior when you run the npm install command. It is designed to manage dependencies for a specific project.

Storage Location: Packages are installed inside the node_modules directory of the project where the command is run. They are also added to the project’s package.json file under dependencies or devDependencies.
Access: These packages can only be imported and used within that specific project via require() or import statements. They are not accessible globally from the command line unless run via an npm script or npx.
Best Used For: Frameworks, libraries, and utilities that your project’s code directly relies on to run (e.g., React, Express, Lodash, or Jest).
Command: npm install <package-name>

Global Installation

A global installation makes a package available system-wide, allowing you to run its commands directly from your terminal regardless of your current directory.

Storage Location: Packages are stored in a single, centralized system directory (such as /usr/local/lib/node_modules on macOS/Linux or %AppData%\npm\node_modules on Windows). They are not added to any project’s package.json file.
Access: The executable binaries of these packages are added to your system’s PATH, making them executable from any command-line interface (CLI) window. They cannot be easily imported into your local project files using require() or import.
Best Used For: CLI tools, generators, and development utilities that you use across multiple projects (e.g., nodemon, aws-cli, or typescript).
Command: npm install -g <package-name>

Key Differences Summary

Feature	Local Installation	Global Installation
Command	`npm install <package-name>`	`npm install -g <package-name>`
Storage Location	Project-specific `node_modules/` folder	System-wide node directory
Project Dependency	Listed in `package.json`	Not listed in `package.json`
Usage	Imported into project code (`require`/`import`)	Run as commands in the terminal
Scope	Restricted to the project directory	Accessible across the entire system
Version Control	Locked per project, ensuring consistency	Shares one version across all projects

A Modern Alternative: npx

For CLI tools that you only need to run occasionally, you can avoid global installations entirely by using npx. Running npx <package-name> downloads and executes the tool temporarily without permanently installing it globally on your system. This ensures you always use the latest version and keeps your global space clutter-free.