Glossary · Web Development

npm (Node Package Manager)

npm is the default package manager for Node.js and the largest public registry of JavaScript packages, used to install and manage project dependencies.

Updated October 6, 2026

npm (Node Package Manager) is a command-line tool and public registry for downloading, publishing and managing JavaScript packages. A project lists its dependencies in package.json and installs them into a node_modules folder.

Why it matters

Almost every modern web project depends on dozens or hundreds of packages, directly or through other packages. That speeds up development and introduces supply-chain risk, because a compromised or abandoned package affects your build. A lock file records exact versions so every install is reproducible. Pinning versions and reviewing updates keeps a surprise dependency change from taking your build or site down.

Example

$ npm install express
$ npm run build

The first command adds express to dependencies in package.json and updates package-lock.json. The second runs the script named build defined in the same file.

Common mistakes

  • Not committing the lock file, so builds differ between machines.
  • Running npm audit fix --force blindly, which can introduce breaking upgrades.
  • Committing the node_modules folder to version control.

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