On release, Wunderlist was a smash success. It quickly reached millions of adoring users.
Wunderlist 2 was even more successful. Not only did we reach millions more users, but our new and existing users became even more active. We released native clients on Mac, Windows, iOS, Android, and the Web. We were featured in every important app store, were among the first featured Chrome OS applications on the market and ended the year being chosen as Apple's 2013 App of the Year.
After such a successful year, it may strike you as odd that we decided to rewrite almost everything from scratch.
This talk will describe the motivation behind the technical re-architecture of Wunderlist 3 and walk through lessons learned in scaling a cross-platform, multi-client, collaborative synchronization system.