This was a social networking application I created in my free time using iOS and Firebase. It allowed for friends to chat anonymously with each other within an iOS client app. I discontinued this, but all the client code is open source. This 'real' project taught me the importance of having a well architected app!
It was a great learning experience, and was the first time that I had used any of the Firebase suite of products, which I continue to use today. When working on this project, the Firebase Realtime Database was still very new and very cool that it was so easy to implement realtime features.