Silex: It's the biggest microframework you'll ever use. Or maybe the most lightweight framework you'll ever use. Or it's just Symfony Junior. So what is it? Silex is, simply, a ready-made request/response pipeline built on the Symfony components, ready for you to build... whatever. Unlike fullstack frameworks it doesn't imply a certain model or approach, and lets you define your own architecture, for better or worse. In this session we will, before your very eyes, build up a small but functional Silex application from nothing but a composer.json file to a fully capable REST service. Along the way we'll show how to keep you system decoupled and testable, without falling into the “anonymous callbacks are so easy; wait, now I can't test anything” trap. And best of all, it will offer a direction for people who want to do more than “hello world” but don't know where to start without the pre-build scaffolding that a fullstack framework would provide.