POAPs Denver Quest

A cross-chain solution for POAP verification and prize distribution using Celo and Avalanche networks.

Contract Addresses

Contract	Network	Address
POAPVerifier	Celo Mainnet	0x3449afc2fCF3D51DC892658f0c69E47286B078d4
Raffle	Avalanche C-Chain	0x2e3b71cF183657582F03c44F35fECF235677C1ED

Project Overview

This project implements a cross-chain solution for verifying POAP ownership and conducting a raffle:

1. POAP Registration: Users mint POAPs on the Celo network, generating unique tokenIds for each participant
2. Verification Process: The POAPVerifier contract validates POAP ownership
3. Cross-Chain Raffle: Validated participants enter a Chainlink VRF-powered raffle on Avalanche

Setup Guide

Installation

# Install dependencies
npm i

# Set up environment variables
cp .env-example .env
# Edit the .env file with your private keys and API endpoints

Development Workflow

Testnet Deployment

POAP System

# Deploy Mock POAP contract
npm run testnet:deploy:mockpoap

# Deploy POAP Verifier contract
npm run testnet:deploy:poapverifier

# Mint test POAPs
npm run testnet:mint:poaps

Raffle Setup on Testnet

1. Using the Coordinator contract, execute createSuscription() and get subscriptionId from logs
2. Set environment variables for the Raffle contract in your .env file
3. Deploy raffle contract: npm run testnet:deploy:raffle
4. In Coordinator contract, execute addConsumer(subId, raffleAddress)
5. Fund the subscription with LINK tokens: execute transferAndCall(coordinatorAddress, 1000000000000000000, abi.encode(subId)) from the LINK token contract
6. On the Raffle contract, execute electWinners() to randomly select winners

Contract Verification

# Verify Mock POAP contract
npx hardhat verify --network alfajores <MOCK-POAP-ADDRESS>

# Verify POAP Verifier contract
npx hardhat verify --network alfajores --constructor-args poapVerifierArgs.js <POAP-VERIFIER-ADDRESS>

# Verify Raffle contract
npx hardhat verify --network fuji --constructor-args raffleArgs.js <RAFFLE-ADDRESS>

Mainnet Deployment

POAPVerifier Deployment

# Deploy POAP Verifier contract to Celo mainnet
npm run mainnet:deploy:poapverifier

# Verify the contract
npx hardhat verify --network celo --constructor-args poapVerifierArgs.js <POAP-VERIFIER-ADDRESS>

Raffle Setup on Mainnet (Avalanche)

1. On Chainlink Coordinator contract: execute createSuscription() and get subscriptionId from logs
   • Coordinator Contract
2. Set environment variables for the Raffle contract
3. Deploy raffle contract: npm run mainnet:deploy:raffle
4. In Coordinator contract, execute addConsumer(subId, raffleAddress)
5. Fund the subscription with LINK tokens: execute transferAndCall(coordinatorAddress, 1000000000000000000, abi.encode(subId)) from the LINK token contract
   • LINK Token Contract
6. On the Raffle contract, execute electWinners() to randomly select winners

# Verify Raffle contract
npx hardhat verify --network avalanche --constructor-args raffleArgs.js <RAFFLE-ADDRESS>

Project Workflow

1. POAP Registration and Collection

As users participated in the Denver Quest, they minted POAPs on the Celo network. Each minted POAP generated a unique tokenId associated with the participant's address.

2. Generating Participant List from POAP Events

After the POAP minting period, we extracted the events to create a list of all participants:

# Script to fetch events and compile list of participants
node events/index.js

# Generate token IDs and tokenId-owner pairs
node events/getIdsFromParticipants.js

This process generated:

• tokenIds.json: An array of all valid token IDs
• tokenIdOwnerPairs.json: An array of objects matching each tokenId to its owner

3. Verification and Registration Closure

The registration period ended on March 16th. We finalized the process by:

1. Submitting all tokenIds to the POAPVerifier contract for validation
2. The verification transaction can be viewed here: Verification Transaction
3. All registered users can be verified in this transaction: Registered Users

4. Cross-Chain Raffle

The final list of verified participants was then:

1. Extracted from the POAPVerifier contract on Celo
2. Imported into the Raffle contract on Avalanche C-Chain
3. The Raffle contract used Chainlink VRF 2.5 to randomly and fairly select winners

The winner selection process was completed with the following transactions:

• Initial electWinners() execution: Transaction Hash
• Chainlink VRF fulfillment (internal transaction): VRF Transaction Hash

Technical Architecture

• POAPVerifier (Celo): Validates POAP ownership and maintains the official list of participants
• Raffle Contract (Avalanche): Manages the selection of winners using Chainlink VRF for verifiable randomness
• Cross-Chain Integration: Manual transfer of verified participant list from Celo to Avalanche

Additional Resources

For technical questions or contributions, please open an issue in this repository.