Full-stack take-home: multiplayer bingo in realtime with Express, React and Socket.io. In-memory room state, no MongoDB — built to prove Node and WebSocket mastery in a hiring process.
0
DB dependency for match state
1
Process: HTTP + sockets + SPA
Socket.io
Realtime transport
Deliver a credible realtime product under take-home constraints: multiple clients must share one authoritative match clock, handle late joins and disconnects, and stay correct without a database or a heavy REST surface. Polling would break the sync contract; the architecture had to show intentional Socket.io design.
I co-located Express and Socket.io in one Node process: HTTP for the React build and card generation (`/get_board`), sockets for the entire match lifecycle. Socket rooms separate lobby, in-progress and results; the host controls start/end; balls broadcast as events; line/bingo and abandon paths keep the room consistent. In-memory state was an intentional trade-off — right for short shared-link sessions and a clear demo of server-authoritative realtime design.
A production-deployed demo (Render) where a recruiter opens two tabs and immediately sees synchronized lobby → match → results. It shows I can own the realtime path: protocol design, room lifecycle, React UI phases and ops — not just wire up a library.
Match status and the shared drum live on the Node process; clients render phases from socket game state, not from ad-hoc HTTP polling.
Isolated lobby / playing / results rooms, host lifecycle, late-join rejection and mid-game abandon without collapsing the match.
One service ships API, sockets and SPA; Webpack build served by Express. No MongoDB where it would not add value.
Share one URL, open two tabs: two players, live ball sync and win flow — technical depth visible in under a minute.
Tell me what you are trying to build and I will tell you honestly what it takes to ship it.
