It's primarily a bundle maker a la browserify. The main difference is that it stretches the definition of module beyond just javascript. It can seem like a buil

It's primarily a bundle maker a la browserify. The main difference is that it stretches the definition of module beyond just javascript. It can seem like a build system because you can set up rules to run a particular filter on a matching set of files. An example: run files ending with .sass through sassc. The difference is that webpack always starts at an entry point and only walks the dependency graph. If you want to include a sass file, you need to `require('foo.sass')` (without assigning it to anything) from your foo.js. It will then inline the resulting CSS into the single output bundle.js file and you'll have to split out the CSS with another plugin if you want it in a different file. If you're just using grunt/gulp to build assets then using webpack will save you effort/maintenance but if you also need to copy files around, ping servers, kick of CI, or some other side effect then you'll need some shell script or build runner in addition.