gulp is an open-source JavaScript toolkit created by Eric Schoffstall[4] used as a streaming build system (similar to a more package-focussed Make) in front-end web development.

It is a task runner built on Node.js and npm, used for automation of time-consuming and repetitive tasks involved in web development like minification, concatenation, cache busting, unit testing, linting, optimization, etc.[5]

gulp uses a code-over-configuration approach to define its tasks and relies on its small, single-purpose plugins to carry them out. The gulp ecosystem includes more than 3500 such plugins.[6]

Wiki Source: https://en.wikipedia.org/wiki/Gulp.js