Dive into the fourth installment of a comprehensive video series on Python Web3 development, focusing on connecting the frontend and backend of a decentralized application. Learn how to finish the backend, set up the frontend, integrate Metamask, create challenges, implement cryptography and hashing, send inputs, and test the application. Explore the Cartesi library, which enables Web3 development in various programming languages beyond Python. Gain insights into app-specific rollups, modular scaling solutions, and the broader design space for DApp developers. Access valuable resources, including setup guides for different operating systems, GitHub repositories, and opportunities for seed grants in Cartesi development.