Flowchart of project
Landing page
Login Page
Company Dashboard page
Create Campaign page
Funding the Campaign
Download Qr Codes
User Dashboard
Browse Offers
Claiming Prize

WinScan – Scan. Verify. Win.

A Web3-powered QR reward system built to make promotions trustless, transparent, and tamper-proof.

Inspiration

"The real turning point began with the infamous McDonald’s Monopoly scam."

Over 12 years, insiders rigged McDonald’s promotional campaigns and embezzled $24M worth of rewards. It exposed a critical flaw: no transparency, no accountability, no public trust.

Even today, offers like "Scan to Win ₹5 Lakhs" are met with skepticism. Most people assume it's just another scam.

That’s when it struck me — what if trust was no longer needed at all?
What if the system was verifiable by design?

Inspired by this , I envisioned a platform powered by blockchain that guarantees:

Immutable reward logic
On-chain verification
No human interference

What is WinScan?

WinScan is a Web3-based QR reward platform where verified companies launch promotional campaigns using Ethereum smart contracts.

Companies lock ETH as prize funds
QR codes are generated and distributed
Users scan via camera or image upload
If eligible, users receive rewards directly from the smart contract

No middlemen
No manipulation
Fully traceable & verifiable rewards

How We Built It

Frontend:

Built with React.js & Tailwind CSS
Integrated camera/image-based QR scanning using qr-scanner
Used Bolt AI for rapid UI prototyping and design iterations

Backend:

Developed using Node.js + Express
Stored campaign & user data in MongoDB
Implemented JWT + cookies for secure authentication

Smart Contract Layer:

Written in Solidity
Deployed on Ethereum Sepolia Testnet
Managed contract interactions using Ethers.js & Web3.js
ETH locked & distributed directly via smart contract logic

Challenges We Faced

Gas Optimization
- Ensuring cost-effective yet secure reward logic without loopholes.
Mobile Wallet Integration
- Mobile MetaMask support was tricky due to browser limitations.
QR Code Abuse Prevention
- Implemented hybrid validation: on-chain checks + backend QR status tracking.
User Onboarding
- Educating users unfamiliar with blockchain via tooltips and real-time transaction feedback.

Accomplishments We’re Proud Of

Fully functional testnet demo with live ETH rewards
Designed an AI-generated responsive UI using Bolt AI
Achieved full QR traceability with smart contract + backend sync
Successfully implemented one-time QR usage enforcement
Separated flows for B2B (brands) and B2C (users)
Submitted for Solidity smart contract patent

What We Learned

Code is Law — Smart contracts are powerful, but unforgiving.
UX is Everything — People won’t trust what they don’t understand.
Transparency = Trust — Showing users their Etherscan transaction hash boosted confidence like never before.

What’s Next?

Launch on Ethereum Mainnet with real brands (Pepsi, Lays, D2C startups)
Integrate Chainlink VRF for provably fair prize randomness
Release mobile app with offline QR scan support
Launch company analytics dashboards with heatmaps, engagement tracking, and claim stats