CleanChain

welcome page
map page
community gallery
user dashboard
user dashboard

Inspiration

While cities spend millions on sanitation, everyday litter often goes unnoticed. We were inspired to build a solution that directly incentivizes citizens to take action. By combining Web3 and community trust, we wanted to create a decentralized system where people are rewarded for cleaning public spaces — without relying on centralized authorities.

What it does

CleanChain-V2 is a decentralized application (dApp) that verifies and rewards real-world cleanups using a community-driven voting system and on-chain token incentives. Users upload geotagged “before” and “after” photos of cleaned areas. Other users then vote to validate the effort. Once a threshold is met, the cleanup is verified and rewarded with ECO tokens via smart contract. The system includes:

Wallet-based authentication (Metamask)
Geolocation + photo uploads
Voting system for verification
ERC-20 token rewards
Admin dashboard & user profiles

How we built it

We used a full-stack Web3 architecture:

Frontend: React (Vite) + TailwindCSS for UI
Backend: Node.js + Express.js for API routing
Database: Firebase Firestore for user/location/vote storage
Blockchain: Solidity smart contracts deployed using Hardhat
Wallet integration: Ethers.js for blockchain interaction
Smart Contract: Custom ERC-20 ECO token with reward transfer logic

We followed a modular folder structure with routes for auth, voting, uploads, and smart contract interaction.

Challenges we ran into

Designing a trustless verification mechanism without oracles or AI
Preventing abuse (e.g., self-voting or duplicate cleanups)
Getting Firebase and smart contract logic to sync without race conditions
Managing environment variables securely for backend deployment
Time constraints in building an entire reward flow from scratch (upload → vote → token transfer)

Accomplishments that we're proud of

Built and deployed a working token economy with real-time reward flow
Created a clean and intuitive UI for wallet-based interactions
Integrated Web2 (Firebase) and Web3 (Solidity) smoothly
Designed a project that solves a real-world sustainability problem
Learned how to make something that feels like a real Web3 product, not just a demo

What we learned

Deepened our understanding of smart contract development and deployment
How to build secure Web3 APIs while managing off-chain data
Balancing decentralization with usability — especially in voting and validation mechanisms
The importance of thoughtful UX in Web3 projects
How to debug complex systems with multiple moving parts (DB, wallet, blockchain)