3balance

3balance is an onchain mini app where players pick a crypto character, fight in a fast 1v1 arena, and record the result on Base.

The core idea is simple: every new match starts with an onchain action. Gameplay is offchain and instant, while entry analytics stay transparent onchain.

What It Does

• Sends an onchain enterMatch(characterId, won) transaction after battle resolution.
• Uses Base Account + OnchainKit MiniKit inside Base App.
• Supports sponsored gas flow through Coinbase Paymaster when available.
• Shows player profile from MiniKit context (displayName, username, avatar).
• Runs battle gameplay with character selection, lives, coin control, AI behavior, and win/lose states.
• Supports result sharing to feed via composeCast, with browser fallback (navigator.share or copy link).

Game Flow

1. Open app.
2. Pick fighter.
3. Fight opponent in arena.
4. Sign the onchain result transaction on Base.
5. Share result.

Tech Stack

• React 19 + Vite 7
• wagmi + viem
• @coinbase/onchainkit
• Base Mainnet
• Solidity (entry contract)

Smart Contract

Contract source: contracts/BattleArenaV2.sol

Main entry function:

function enterMatch(string calldata characterId, bool won) external payable

The contract stores:

• Total entries
• Unique players
• Entries per player and per character
• Wins, losses, and current win streak per player
• Last entry timestamp per player
• ERC721 reward mint when a player reaches a 3-win streak

Environment Variables

Create .env.local and set:

VITE_PUBLIC_ONCHAINKIT_API_KEY=your_onchainkit_api_key
VITE_BATTLE_ENTRY_CONTRACT=0xYourBattleArenaEntryContract
VITE_APP_URL=https://3balances.vercel.app

Notes:

• VITE_BATTLE_ENTRY_CONTRACT has a default fallback in src/App.jsx if env is missing.
• Paymaster RPC URL is currently configured directly in src/App.jsx.
• Current Base mainnet deployment: 0x09C1FaD72f10c0Dd4C083A28990Faa8A7C8F0580

Local Development

pnpm install
pnpm dev

Build and checks:

pnpm lint
pnpm build
pnpm preview

Mini App Metadata

Metadata files:

• public/.well-known/farcaster.json
• index.html (fc:miniapp tag)

Screenshots and cover assets:

• public/cover-1200x630.png
• public/screenshots/screenshot-1.png
• public/screenshots/screenshot-2.png
• public/screenshots/screenshot-3.png

Assets

Character images:

• public/battle/characters/

Coin icons:

• public/battle/coins/

Project Structure

• src/App.jsx - app shell, wallet/profile, entry tx, share logic, navigation
• src/BattleArena.jsx - game screen and mechanics
• src/main.jsx - OnchainKit provider bootstrap
• contracts/BattleArenaV2.sol - onchain match entry and streak reward contract

Current Status

• Main gameplay and onchain result recording flow are live.
• Browser fallback is enabled if MiniKit is unavailable.
• UI is optimized for mobile mini app usage.

License

MIT