Implementation of Smart Contracts with Blockchain Technology in Building a Web 3.0-Based Decentralized Finance Crowdfunding System on the Ethereum Network

Crowdfunding is a widely used method for raising funds, yet existing platforms often suffer from transparency issues, security vulnerabilities, and centralized control. This study proposes a decentralized crowdfunding system built on the Ethereum blockchain, utilizing smart contracts to enhance trust and automate transactions. The system incorporates a simple majority voting mechanism, in which at least $50 \%+1$ of donors must approve any fund withdrawal, thereby improving accountability and reducing fraud potential. Developed using the Scrum methodology, the system was tested through black-box validation and successfully executed core features including campaign creation, contribution, voting, and withdrawal. The results confirm that the implementation ensures transaction immutability, accurate donor verification, and transparent fund management, demonstrating the potential of blockchain-based crowdfunding to overcome the limitations of traditional platforms.