District 10
Game mechanics on top of a server network I also run — including an in-house CDN and a streaming engine for in-game live video and calls.
Full-stack in the literal sense: game mechanics at one end, the machines they run on at the other. Server network administration sits in the middle, which is where most of the interesting problems are.
The delivery layer is built in-house rather than bought — a CDN and caching tier of my own, because the traffic shape of a live game world is not the traffic shape a general-purpose CDN is priced and tuned for.
On top of that, a streaming engine that carries live video inside the game world, including face-to-face calling between players. Real-time video is the part of this that has no forgiving failure mode: it either arrives in time or it is not a call.