I have a group of friends who have, since 2018, gathered online every Monday night to play Super Smash Bros. Ultimate, a Nintendo game. We love the game, its personality, and its environment, but there is a distinct lack of online features, such as the ability to set up casual tournaments with friends. Several years ago I set out to correct this by creating a Node.JS app which we could use for football-style drafts, tracking wins over periods longer than a single night, and various other features that my group and I brainstormed together.
Since its inception features have been added, half-forgotten, redesigned, and torn down and rebuilt. At first it was strictly a Twig-based Node.JS app that utilized websockets via socket.io on an express.js framework, but I later gave it a complete makeover in React (still using sockets and express) which is how it's currently living.
Mobile-wise, it works! This is how half of my testbase interacts with it, but "it works" is a very low bar, which I only allow for personal projects.
You can take a peek at the app (assuming it hasn't crashed) over at smashcrowd.jeffwayde.com. Assuming I haven't implemented logins and usernames yet, feel free to take control of a player and see what happens.