Reading the SPFx documentation I find it difficult to understand which service/tool/framework handles requests as a web server. From documentation both Node and Gulp can be used as a web server during development.
Node is a runtime which makes me think it's close to CLR on Windows machines. Gulp on the other hand is a task runner which makes me think it's an IIS website or its application pool. If I start
gulp serve I can access my webpart in localhost. If I stop it, I can't.
Does Node or Gulp act as webserver during webpart development?