Decentralized applications (DApps) in Web3 not only change the way we use the internet but also lead a technological revolution. Traditional applications rely on centralized servers and third-party institutions to store and manage data, while DApps use blockchain technology to store all data on a decentralized network, making it tamper-proof. This decentralized structure brings unprecedented trust and transparency. Since the execution of smart contracts is automated, DApps reduce the possibility of human interference, ensuring fairness in the system. In the financial sector, DeFi (decentralized finance) is based on this form of decentralized applications, offering financial services without intermediaries through smart contracts. As the technology continues to evolve, DApps will become more diverse, covering multiple fields from entertainment to governance.