🎟️ FairPass – NFT-based Event Ticketing

Demo Video link : https://youtu.be/c5NRRpHysRg

Transparent · Secure · Fair

FairPass is a blockchain-powered ticketing platform built on the Sonic Blockchain, utilizing NFTs to bring fairness, transparency, and security to event ticketing.

• ✅ No Fraud → Tickets are unique NFTs
• ✅ Fair Resale → Ownership is transparent on-chain
• ✅ Privacy at Check-in → Uses Zero-Knowledge Proofs (ZKPs) so users prove ticket validity without exposing their wallet
• ✅ Sonic FeeM → On Sonic Mainnet, 90% of gas fees are refunded back to the smart contract owner, creating a sustainable revenue model that rewards both the platform and organizers without overcharging users. (FeeM is not available on testnet)

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🚨 The Problem

🎫 Web2 ticketing is broken:

• Fake/scalped tickets → fans get cheated.
• Organizers lose resale revenue.
• Users expose personal info at check-in.

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💡 Our Solution

FairPass turns every ticket into an NFT with built-in ZK privacy:

• Tickets can’t be faked (NFTs are unique).
• Resale rules are enforced on-chain.
• At check-in, you prove ownership via ZK proof → without revealing wallet.
• Sonic’s FeeM refunds 90% of gas → organizers earn more, users pay less.

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📑 Table of Contents

1. Tech Stack
2. Core Smart Contracts
   • EventImplementation.sol
   • EventTicket.sol
   • EventManager.sol
3. Fee & Incentive Model
4. Ticket Lifecycle
5. Example Flow

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🛠 Tech Stack

• Blockchain: Sonic
• Smart Contracts: Solidity, Foundry
• Tickets (NFTs): ERC-721
• Privacy: Zero-Knowledge Proofs (semaphore.js)
• Frontend: React
• Backend: Node.js, Express
• Wallet Integration: Rainbow-Kit

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🔑 Core Smart Contracts

1. EventImplementation.sol

Handles event-specific logic:

• constructor() → Initializes event (name, type, price, organizer, platform)
• buyTicket(string metadataURI) → Users purchase tickets, NFT minted
• mintForUser(address user, string metadataURI) → Organizer batch/lazy mints tickets
• checkIn(uint256 tokenId, ZKProof proof) → Validates ZK proof & burns ticket after check-in
• ownerOfNFT(uint256 tokenId) → Returns NFT owner
• registerMe() → Organizer registration
• Ownership management → owner(), transferOwnership(), renounceOwnership()

✅ ZK Integration → Prevents fraud (e.g., screenshot reuse of tickets)

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2. EventTicket.sol

ERC-721 contract for tickets:

• mint(address to, string metadataURI) → Mints NFT ticket
• burn(uint256 tokenId) → Burns ticket (used after check-in)
• ownerOf(uint256 tokenId) → Returns ticket owner
• tokenURI(uint256 tokenId) → Metadata (IPFS link)
• Standard ERC-721 transfers → transferFrom, safeTransferFrom

✅ ZK Context → Tickets verified without exposing wallet

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3. EventManager.sol (0x9016F1b7DA5C91d6479aAF99A8765Cb4ED0668bE)

Deploys and manages multiple events:

• createEvent(...) → Deploys new EventImplementation contract
• getAllEvents() → Returns list of deployed events
• getEventDetails(eventAddress) → Fetch event details

✅ ZK Enforced → All events require ZK proof at check-in

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💰 Fee & Incentive Model

FairPass leverages the Sonic blockchain’s fee-sharing model and mainnet token rewards:

Revenue Source	Organizer	Platform (FairPass)
Ticket Sales	100%	0%
Resale Fees	Shared	Shared
Gas Refunds (Sonic)	Shared	Shared (90% of fees returned)
Mainnet Token Rewards	✅ Earn tokens per transaction	❌

👉 This creates a sustainable revenue stream while ensuring fair costs for users.

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🔄 Ticket Lifecycle

1. Mint/Buy → NFT ticket minted to user
2. Resell/Transfer → Allowed with enforced platform fee
3. Check-In (ZK proof) → Proof generated → verified on-chain → ticket burned
4. Completion → Ticket cannot be reused

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🧩 Example Flow

1. Organizer creates event via EventManager
2. User buys ticket through EventImplementation
3. Ticket minted in EventTicket contract
4. At venue:
   • User generates ZK proof
   • Calls checkIn(tokenId, proof)
   • Proof verified → ticket burned
5. If resold, resale fees distributed to platform + organizer

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🌍 Why Sonic + Hackathon Fit

1. FeeM gas refund → sustainable incentive model

2. ZK privacy → innovative check-in UX

3. NFT tickets → transparent + fair resale

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📂 Project Structure

backend/   → Node.js + ZKP service  
frontend/  → React dApp (UI, wallet integration)  
web3/      → Solidity contracts (EventManager, EventImplementation, EventTicket)

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Contributors

1. Fabio Mughilan
2. Siddarth

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