Chain11

A fully decentralized fantasy sports platform built for EVM with Chainlink Functions for trustless score oracle and settlement.

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🏏 Features

• Create Contests — Anyone can create a fantasy contest for any cricket match
• Join & Submit Teams — Pick 11 players, captain (2×), vice-captain (1.5×)
• Automatic Settlement — Chainlink fetches scores and calculates winners off-chain
• Decentralized Prizes — Top 3 or Top 10 winners split the pool
• Gas Optimized — Batch operations, compressed contracts, <24KB each
• Scalable — Handles 600+ participants per contest

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🏗️ Architecture

┌──────────────────────────────────────────────────┐
│              Chain11.sol (22KB)                  │
│  • Contest management                            │
│  • Team validation (batched)                     │
│  • Prize distribution                            │
└───────────────────┬──────────────────────────────┘
                    │
                    ▼ calls
┌──────────────────────────────────────────────────┐
│            Chain11Oracle.sol (19KB)              │
│  • Chainlink Functions integration               │
│  • Match initialization (squad data)             │
│  • Score fetching (fantasy points)               │
│  • Settlement calculation (off-chain)            │
└───────────────────┬──────────────────────────────┘
                    │
                    ▼ requests
┌──────────────────────────────────────────────────┐
│              Chainlink DON                       │
│  • Fetches match data from Cricket API           │
│  • Fetches final scores                          │
│  • Calculates winners (batched RPC calls)        │
│  • Returns top K winners                         │
└──────────────────────────────────────────────────┘

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📦 Installation

Prerequisites

node >= 18.0.0
npm >= 9.0.0

Setup

# Clone repository
git clone https://github.com/DaevMithran/chain11.git
cd chain11

# Install dependencies
npm install

# Copy environment template
cp .env.example .env

Environment Variables

# .env
PRIVATE_KEY=                              # Deployer wallet private key
BASE_RPC_URL=https://mainnet.base.org     # Base mainnet RPC
BASESCAN_API_KEY=                         # For contract verification

# Chainlink Functions
CHAINLINK_ROUTER_ADDRESS=0xf9B8fc078197181C841c296C876945aaa425B278
CHAINLINK_DON_ID=0x66756e2d626173652d6d61696e6e65742d310000000000000000000000000000
CHAINLINK_SUBSCRIPTION_ID=                # Your Chainlink subscription ID

# Contract addresses (set after deployment)
ORACLE_ADDRESS=
CORE_ADDRESS=

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🚀 Quick Start

1. Compile Contracts

npx hardhat compile

2. Run Tests

# All tests
npx hardhat test

# With gas reporting
REPORT_GAS=true npx hardhat test

3. Deploy to Testnet (Base Sepolia)

# Create Chainlink subscription first:
# https://functions.chain.link (Base Sepolia)

# Deploy Oracle
npx hardhat run scripts/deploy-oracle.ts --network base-sepolia

# Deploy Core
export ORACLE_ADDRESS=0x...
npx hardhat run scripts/deploy-core.ts --network base-sepolia

# Link contracts
export CORE_ADDRESS=0x...
npx hardhat run scripts/link-contracts.ts --network base-sepolia

4. Verify Contracts

npx hardhat verify --network base-sepolia $ORACLE_ADDRESS \
  $CHAINLINK_ROUTER_ADDRESS \
  $CHAINLINK_DON_ID \
  $CHAINLINK_SUBSCRIPTION_ID

npx hardhat verify --network base-sepolia $CORE_ADDRESS \
  $ORACLE_ADDRESS

Expected gas costs:

• Create contest: 200k gas ($0.04)
• Join & submit team: 59k gas ($0.01) — optimized with batch validation
• Settlement: 300k gas ($0.06) — constant, regardless of participants

💰 Tokenomics

Fees

Contest creation: 0.01 ETH
Team entry:       0.01 ETH
Platform fee:     10% of all entries

Prize Distribution

3-9 participants (Top 3):

1st: 50% | 2nd: 30% | 3rd: 20%

10+ participants (Top 10):

1st: 30% | 2nd: 15% | 3rd: 10% | Ranks 4-10: 5% each

Chainlink Costs (per contest)

Match initialization: ~0.3 LINK  (~$1.50)
Score fetching:       ~0.3 LINK  (~$1.50)
Settlement:           ~0.3 LINK  (~$1.50)
Total:                ~0.9 LINK  (~$4.50)

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🛠️ Tools & Technologies Used

Category	Tool	Version	Purpose
Language	Solidity	0.8.28	Smart contracts
Framework	Hardhat	2.22+	Development environment
Library	Viem	2.x	Contract interactions
Oracle	Chainlink Functions	1.0.0	Off-chain data & compute
Build	Terser	Latest	JS minification
Optimizer	Via IR	Built-in	Code optimization

📝 License

MIT License - see LICENSE for details.

🗺️ Roadmap

• Core contract implementation
• Chainlink Functions integration
• Test suite
• Frontend dApp (React)
• Mobile app (React Native)
• Multi-sport support

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