Celo

BlockdareBasic is a lightweight, on-chain challenge logging system built using Solidity. It enables anyone to record a verifiable challenge entry—containing the challenger’s address, a brief description, and a timestamp—directly onto the blockchain. Designed for fairness and transparency, every entry is permanent and publicly accessible, making it ideal for competitions, gaming communities, and audit-friendly environments. With a compact structure and event-based updates, the contract ensures…

ChainHealth is a simple verifiable medical data ledger for individuals. It allows users to register themselves and store verifiable hashes of medical records on-chain for audit and verification — without exposing private data. Built using Solidity (compiled to Solana via Solang), it provides a privacy-preserving, tamper-proof registry for patient health record hashes.

The On-Chain Quiz System is a blockchain-powered quiz application where questions, answers, and user scores are stored on the blockchain to ensure transparency, trust, and tamper-proof results. This project demonstrates how smart contracts can be used for education, certification, and fair evaluation by removing the possibility of cheating or data manipulation. Github link :https://github.com/ankit79600/Quizchain

ProofCert is a beginner-friendly Solidity smart contract that enables users to store and verify their earned credentials immutably on the blockchain. It’s designed to make academic and professional certificates permanent, verifiable, and tamper-proof, removing the need for centralized verification systems.

⚡ Simple Flash Loan Provider (Solidity) A beginner-friendly Flash Loan Provider smart contract built with Solidity (v0.8.19). This project demonstrates the core mechanics of flash loans — instant, no-collateral loans that must be repaid within the same blockchain transaction. 🧠 Project Description This project is a simplified educational example of how a flash loan works under the hood. Flash loans are commonly used in DeFi (Decentralized Finance) protocols for arbitrage, liquidation, and…

WORDFI is a blockchain-based word guessing game built with Solidity. Players try to guess a secret word within a limited number of attempts, and the smart contract automatically verifies the correct word once the game ends. https://github.com/aryan1gupta-ux/wordfi.sol

Traditional event ticketing systems often suffer from problems like counterfeiting, hidden fees, and centralized control. EventFi solves these issues by providing a trustless, transparent, and tamper-proof platform for managing event tickets. With EventFi, event organizers can: Create and manage their events on-chain. Sell tickets directly to users for a set price. Withdraw funds safely after ticket sales. And users can: Buy tickets securely using cryptocurrency (ETH). Own verifiable,…

Traditional book lending systems rely on centralized databases that can be edited, deleted, or lost. Biblioblock solves this by using blockchain technology to create an immutable ledger of book transactions. Every book addition, lending, and return is permanently recorded on-chain — forever traceable and verifiable. github link:- https://github.com/nathanpaul28/Biblioblock

HalloApp is a beginner-friendly Solidity smart contract that allows users to save Ether, withdraw funds, and view their transaction history — directly on the blockchain. Think of it as your decentralized savings account, where you’re your own bank.

The Library Management System (LMS) is a Solidity-based smart contract deployed on the Ethereum blockchain that enables a decentralized and transparent way to manage library operations. The contract allows the librarian, acting as the system owner, to add, update, and remove books from the catalog, while readers can securely borrow and return books. Every action—such as adding a book or borrowing one—is permanently stored on the blockchain, ensuring full transparency, accountability, and an…

NumSum is a decentralized blockchain-based guessing game where players bet small amounts of ETH and try to guess the sum of two random numbers. If the guess is correct, the player instantly wins 2× their bet through an automated smart-contract payout.

MatchRecords is a beginner-friendly Solidity project designed to store and display sports match results on the Ethereum blockchain. It demonstrates how structured data—like team names, scores, and timestamps—can be stored immutably on-chain, ensuring results cannot be altered after publication. GitHub Repository: https://github.com/swapnilsantra2-bit/records-match-results-transparently