Dev Dependency
A dev dependency (development dependency) is a package or library in software development that is only needed during the development, testing, or building of an application, not in its production runtime. It typically includes tools like linters, testing frameworks, build systems, and transpilers. These dependencies are managed separately from production dependencies to keep the final deployment lightweight and focused on runtime essentials.
Developers should use dev dependencies to streamline development workflows, enforce code quality, and automate tasks without bloating the production environment. For example, tools like ESLint for JavaScript linting, Jest for testing, or Webpack for bundling are essential during development but unnecessary in a deployed application. This separation improves deployment efficiency, security, and performance by excluding non-essential code.