A service that takes code with a DLL manifest and produces a server side bundling process
Webpackbin requires this service to operate. The way it works is that Webpackbin makes a post request to the sandbox holding the files, packages and loaders. Webpack-sandbox will create a cookie, held in memory, with some information about the user. Depending on the session state it will create a webpack compiler with the passed in details and also a middleware for the session where the bundle can be requested.
When Webpackbin points to the webpak-sandbox service in its iframe the cookie identifies which bundle to grab. Any changes to files, packages and/or loaders are posted to the sandbox again and the iframe can be refreshed. This is how it communicates.
When packages are passed in to the sandbox it will make a request to webpack-dll. Webpack-dll makes a request for a manifest.json file which holds pointers to where import statements should do their lookups in the separate dll.js file. The manifest is returned and webpack-sandbox bundles up your bin code and injects a script tag which points to the dll.js file. That means when webpackbin loads the iFrame it will load the dll file as well.