CoinDuel
A competitive fantasy crypto trading app that turns real-time market data into fast, head-to-head or league strategy games anyone can play. Draft coins. Manage. Compete.
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Scope:
01 — The Problem
real Trading is Risky. Paper Trading Is Lonely.
Learning to trade crypto means either practicing alone on a simulator, or risking real money you can't afford to lose.
02 — The Solution
make it Social, Competitive, and driven by Strategy and Ego.
CoinDuel turns crypto into a multiplayer game. Draft coins, build a portfolio, and go head-to-head with friends or strangers using real market data.
03 — Market Positioning
Fantasy sports, gamified for crypto.
Existing crypto apps focus on solo trading simulations with no social layer. CoinDuel applies the fantasy sports model — competitive, social, retention-driven. Monetized through a freemium credit system and ad revenue.
04 — Gameplay & Systems
Draft. Manage. Compete.
How the game works under the hood.
How You Play
Players start with 100 credits. Buy and sell coins using real-time market data. Apply boost multipliers to amplify gains at the cost of credits.
How You Win
Scored by real-time price movement weighted by position size and boosts. Different coins, different risk. Adapt your strategy as the contest plays out.
Token-Based Draft
Random draft balanced by a 6-10 token budget. Token cost is determined by market cap. Range of 3-5 coins per draft hand.
ELO Ranking
Every contest result adjusts a player's ELO. Drives matchmaking and leaderboard placement.
Game Modes & Formats
Head-to-head, leagues (6-20 players). Daily and weekly contests. Same core mechanics, different duration and strategy.
Credits & Points
Players start with 100 credits. 1 credit = $100 in simulated buying power. Profits convert to points at the end of each contest.
05 — Monetization Design
Free to Play but More Fun on Premium.
Paying does not give you an advantage, it gives you a better experience.
Freemium Tier
Core gameplay is free. Top 50 coins from different market caps to play. Integrated AdMob placements — non-intrusive, never mid-gameplay.
Premium Tier
Top 200 coins from different market caps to play. Expanded in-game features. Ad-free experience. Private leagues.
06 — Design System & IA
Consistent, Scalable, Intentional.
A system of reusable components and clear navigation patterns built for speed and consistency across every screen.
07 — Technical Architecture
Built to ship cross-platform from day one with a lightweight, scalable backend.
Backend
Supabase handles authentication, player profiles, ELO ratings, and score tracking.
Frontend
React Native with Expo. Single codebase for iOS and Android.
Real-Time Contest Engine
Real-time database syncs contest state across players instantly — score updates, position changes, and timer countdowns all happen live without manual refreshing.
Automated Scoring
A scoring engine continuously recalculates portfolio performance as prices update. Point values, multiplier effects, and win/loss states are all computed server-side.
Payments
Stripe for premium plan subscriptions.
08 — Data & API Integration
Real Data. Real-Time.
Live market data and monetization services integrated into the core experience.
Market Data
CoinMarketCap API delivers real-time price data for 50+ coins across five timeframes. Caching and rate-limit handling ensure the app stays fast even during high-traffic market events.
Player Data
Profiles, scores, ELO ratings, and contest history all sync across devices through Supabase in real time.
09 — AI-Assisted Development
Thorough product design and strategy upfront meant less back and forth during development. Clear references, correct semantics, and well-defined requirements allowed Claude Code to build features with minimal engineering revisions. A solo build shipped in 2 months — possible because the design thinking was done before a single line of code was written.
10 — Outcomes & Next Steps
Almost there… 90% Complete.
Remaining work includes finalizing the live market data API, testing 1v1 and league play end-to-end, testing on Expo and AdMob, and refining UX copy and simplicity before launch.
