Mobile Game · Filed · Comprehensive technical report
Number Strike Baseball
Competitive number guessing with real-time matchmaking and ranked play.
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I. Product Thesis
The classic number baseball game (Bulls & Cows) deserves a social, competitive layer. Real-time PvP transforms a simple logic puzzle into a fast-paced daily habit—matches are quick enough to play between tasks, and the 8-tier ranked system keeps players coming back to climb. With AI fallback matchmaking, there’s always an opponent ready within 5 seconds.
Launch the app and land in the lobby. Pick a match format—Single, Best of 3, or Best of 5—and spend credits to enter. The matchmaker searches for a same-tier human opponent; if none is found within 5 seconds, an AI bot matched to your tier steps in. Each round, both players set a secret 3-digit number, then take turns guessing within a 12-second timer. Each guess returns Strike (correct digit, correct position), Ball (correct digit, wrong position), or Out (not in the secret). Crack the code for a home run. Win the match to earn ELO and climb the 8-tier ladder from Ball Boy to Hall of Fame. After the match, add your opponent as a friend or queue up again instantly.
II. Built Surface — Shipped Features
Real-time PvP matchmaking with per-mode ELO and 8-tier progression from Ball Boy to Hall of Fame
AI bots matched by tier for instant play when no human opponent is available
Server-authoritative game state validation via Cloud Functions to prevent cheating
Friends system with direct match invites, online presence tracking, and deep-link referrals
Three match formats — Single, Best of 3, Best of 5 — with credit-based entry and hourly refills
Multi-language support (EN, KO, JA, ZH, ES) with push notifications for match invites
III. Engineering — How the System Holds Together
Flutter handles the cross-platform UI with Firebase as the entire backend. Matchmaking uses Firestore slot documents per format and tier—when a player queues, the client checks adjacent-tier slots for a live opponent (heartbeat within 60 seconds), and falls back to a tier-matched AI bot after 5 seconds. Game state lives in a single Firestore document per match, with real-time listeners keeping both players in sync. Secrets stay in client memory only—never written to Firestore—while guess validation happens on the defender’s client, which writes results to a turns subcollection. Cloud Functions handle post-game settlement: ELO calculation, credit refunds, match history, and referral rewards, all idempotent via a ratingAppliedAt guard.
“The classic number baseball game (Bulls & Cows) deserves a social, competitive layer.”
IV. Key Editorial Decisions
Server-side game settlement via Cloud Functions to guarantee ELO and credit integrity—adds latency but fairness in ranked play is non-negotiable.
Firestore real-time listeners over WebSockets for game sync—simpler infrastructure at the cost of slightly higher read costs.
Secrets stored only in client memory, never in Firestore—eliminates the possibility of reading opponent secrets from the database.
AI bot fallback after 5 seconds instead of longer queue times—player retention matters more than guaranteed human opponents.
Technical Specifications — Complete Dossier
Status
FILED
Category
Mobile Game
Bureau
Los Angeles
Technologies
Flutter, Firebase, Cloud Functions, Claude Opus 4.6, Gemini AI, Eleven Lab
THE JK JUNG TIMES · End of Full Report · All the code that's fit to ship.