Celo

RockPaperScissors is a decentralized, trustless version of the classic Rock–Paper–Scissors game — built entirely on the Ethereum blockchain using Solidity. This contract ensures fairness by using a commit–reveal mechanism, preventing cheating or front-running during gameplay. Players commit to a hashed move first (without revealing it), and later reveal the move with their secret to determine the winner on-chain. https://github.com/swastika02-git/Swastika

Oreo is a blockchain-based record system designed for schools and universities to securely store and verify student results. Instead of keeping grades or certificates in centralized databases, Oreo stores cryptographic proofs (hashes) of those results on-chain — ensuring that they cannot be tampered with or forged. It’s a simple, transparent, and beginner-friendly implementation built using Solidity and deployable on EVM-compatible chains such as Ethereum, Polygon, or…

SimpleAuction is a beginner-friendly smart contract that demonstrates the fundamentals of building a decentralized auction system on Ethereum. It allows users to place bids in ETH, tracks the highest bidder, manages refunds for overbid participants, and automatically ends after a set duration. This project is ideal for developers who want to understand: > ETH transactions within smart contracts > Safe fund withdrawal patterns > Event-driven design in Solidity

ChainLotto is a tiny, easy-to-read Solidity project that demonstrates how to: 1. accept ETH payments from users (lottery tickets), 2. store participants on-chain, 3. generate a (simple, insecure) pseudo-random winner selection using on-chain block data, 4. transfer the accumulated prize to a winner, and reset the game for the next round. The goal is educational: to show core Solidity patterns (storage, payable functions, events, modifiers) in a compact, readable…

**EduQuiz** demonstrates how blockchain can make learning decentralized, transparent, and rewarding. The contract allows a quiz creator (teacher) to add questions with correct answers, while students (players) can participate by submitting their responses. Each correct answer earns the student points that are securely stored on-chain. This project is ideal for beginners who want to learn: How smart contracts work in Solidity How to use structs, arrays, and mappings Ownership control using…

Doodle Trivia is a blockchain-based quiz application that leverages the immutability and transparency of smart contracts to create a fair and permanent trivia game. Built with Solidity, this dApp ensures that all quiz questions and player scores are stored on-chain, making them tamper-proof and verifiable by anyone. Perfect for developers learning Web3, educators creating decentralized learning platforms, or anyone interested in blockchain gaming! Github…

A decentralized smart contract built on Celo Sepolia Testnet, designed to collect and preserve public opinions permanently on the blockchain. This project demonstrates how blockchain immutability can be used for transparency, trust, and open participation. Project Github link : https://github.com/jayendra08/jayendra

KindChain allows anyone to log their good deeds — whether helping someone, donating, or spreading positivity — so that each act is stored permanently on the blockchain. It shows how blockchain can be used for good causes and community transparency. [Github link ](https://github.com/Rounak-webdev/Cello_Web3)

A simple Solidity smart contract that enables manufacturers to register product warranties on the blockchain and allows users to verify or transfer those warranties easily and transparently. The Smart Warranty Registration & Validation System is a blockchain-based solution for securely recording and verifying product warranties. It replaces traditional paper or centralized warranty systems with a decentralized ledger that ensures transparency, security, and trust between manufacturers and…

AuctionFi is a blockchain-based auction system designed for transparency, fairness, and simplicity. The smart contract allows users to bid using Ether, automatically handle refunds for losing bids, and ensure no further bids are accepted after the auction time ends. It’s perfect for beginners who want to learn how decentralized auctions work on Ethereum! github: https://github.com/adityabanerjee510-bit/web3-workshop.git

The Transparent On-Chain Polling System is a blockchain-based voting platform that ensures secure, transparent, and tamper-proof polling. Using smart contracts, the system handles poll creation, voter registration, vote casting, and automatic result calculation. Every vote is stored on the blockchain as an immutable record, preventing fraud or manipulation. The system maintains voter anonymity while allowing anyone to verify the results, making it a reliable and decentralized solution for…

HealthwithChain is a simple decentralized health record management system built using Solidity. It allows patients to securely store, update, and share their medical records on the Ethereum blockchain, ensuring transparency, security, and immutability. This project is beginner-friendly and serves as a great starting point for learning how to handle access control, data privacy, and smart contract design in Solidity. Github link : https://github.com/NIRBANMANNA/healthchain