How does a local install differ from a global one?

A local install puts a package inside a specific project, in the node_modules folder next to package.json.

A global install puts a package at the system level, so it is available from any project as a CLI tool.

bash

npm install <package>

The package is stored in ./node_modules
An entry is added to dependencies or devDependencies
Available only inside this project
Used for libraries the application needs at runtime or build time (React, Webpack, Axios, etc.)

bash

npm install -g <package>

The package is installed into npm's system directory
Not available as a project dependency
Can be invoked as a terminal command from any directory
Usually used for CLI utilities (for example: nodemon, npm-check, create-react-app)

Trait	Local	Global
Where it installs	Into the project (`node_modules`)	Into the system
Visibility	Only in the project	For all projects
Entry in package.json	Yes	No
What it suits	Project libraries	CLI tools

Short summary: a local install is for project dependencies, a global install is for tools you need to run from anywhere on the system.

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