#HuntTheMouse is Singapore's largest online-to-offline cash hunt — a perpetual, location-based game that runs throughout the year across many campaigns. Close to a million players roam the real world hunting virtual coins, with each season offering a prize pool north of a million dollars. At that scale the map has to track GPS and stream event-driven coin spawns in real time without buckling under load, while the platform must keep adapting to new brands, themes, and markets without rebuilding the game for every campaign.
I owned the frontend end to end, and the live map is the game. Players’ GPS positions and event-driven coin spawns stream in over the socket, so the world updates in real time as silver coins surface and get claimed. Around that core I built the toolkit that keeps the hunt tense: a metal detector that homes in on nearby coins, a coin sonar, placeable beacons, plus missions, stamp cards, an offerwall, and merchant integrations.
The silver coins are the heartbeat of the loop — smaller cash prizes that drop onto the map in real time for players to race toward. Landing on one turns the hunt tactical: a shrink power-up tightens the search circle to pinpoint the exact spot, while a countdown keeps the pressure on — hesitate and the coin is forfeited to the next hunter. Winning kicks off a guided, multi-step KYC and winner-verification flow so a real cash prize can actually be paid out.
The golden coin is the grand prize, and it plays out as a hint-driven treasure hunt I designed the economy for. Players collect and buy rarity-tiered text and photo hints — from common all the way up to SSSR — and spend eliminate-grid hints that black out whole geohash zones, shrinking the search area tile by tile until the map closes in on a single spot. Pricing reacts to where a player is standing and how much they buy, with beacon discounts and free-hint rules, all painted live as geohash overlays.
To keep it maintainable I pulled the two hardest pieces into open-source packages the product now runs on: vue3-maplibre-gl for the interactive MapLibre + Deck.GL layers, and vue-micro-router for the app-like navigation of page stacks, dialogs, and HUD.
What made it hard was never a single feature — it was keeping all of them fast at once. With close to a million players on the same map, every spawn, pickup, and hint purchase had to land instantly, so I leaned on optimistic updates for a zero-latency feel and debounced, layered rendering to hold the map fluid while thousands of markers churned in real time. That discipline is what let the game stay smooth on a mid-range phone in the middle of a live hunt.
The platform scaled to roughly a million users and over a million dollars in prizes, and shipped across multiple brands — partner editions plus merchant tie-ins with DBS, Agoda, AXS, CMC, ShopBack, Longbridge, SPF, Happy Dot, Suntec, Sentosa, Capitaland and Sqkii Vouchers — relaunched through a campaign workflow rather than rebuilt each time.