Sloth Jam is a free cozy party game that runs in the browser at slothjam.com : 64 one-minute party games, a five-track kart race, and a whole island to explore. I make it on my own. The audience is families, which means the device in the room is often an old tablet or a hand-me-down Android phone, not a gaming PC.

This post covers the stack and the handful of tricks that keep it playable on those devices.

The stack

TypeScript + Three.js (r186) for the client, bundled with Vite .

No engine and no model files. There isn't a single glTF or FBX in the repo. Every sloth, tree, kart and building is built in TypeScript from simple shapes with vertex colors.

A shared rules package ( @party/rules ) in a monorepo, imported by both the client and the server, so match scoring and game rules are written once.

A small Node server using ws for the online town.…