You’re on a train to work and you open up the Guardian app on your phone. A tunnel surrounds you, but the app still works in very much the same way as it usually would—despite your lack of internet connection, you still get the full experience, only the content shown will be stale. If you tried the same for the Guardian website, however, it wouldn’t load at all. Native apps have long had the tools to deal with these situations, in order to deliver rich user experiences whatever the user’s situation may be. With service workers, the web is catching up. In this talk Olly will demonstrate how he built an offline page for http://theguardian.com, and discuss potential future use cases. There have been lots of talks about service workers in recent times, but rarely have people used them in production and lived to tell the tale. I hope this talk will inspire people to start using them in production, and educate them on the various caveats they might come across.