The rapid growth of e-commerce has placed considerable strain on traditional logistics systems, prompting a need for innovative solutions to optimize delivery processes and enhance customer satisfaction. This research paper presents a decentralized crowdsourced delivery application that leverages blockchain technology and smart contracts to address the challenges faced by centralized logistics models. The proposed system allows e-commerce companies to outsource product deliveries to carriers from a diverse pool, offering greater flexibility and cost-effectiveness while also enhancing transparency and trust among all parties involved. Built on the Ethereum blockchain, the application manages both the delivery and return processes, generating verifiable proofs of delivery (PoD) and proofs of return (PoR) for each transaction. The paper provides a comprehensive analysis of the system architecture and the implementation of the application using smart contracts. Furthermore, it explores the potential impact of the proposed system on e-commerce companies, carriers, and customers, and identifies challenges and future directions for research and development in this field. The findings of this study contribute to the ongoing discourse on the transformative potential of blockchain technology and crowdsourcing in the e-commerce logistics industry, offering valuable insights into the design and real-world application of a decentralized delivery system.