Cross-chain decentralized applications (dApps) and multi-chain dApps represent two evolving concepts in the Web3 ecosystem, driven by the increasing demand for blockspace across numerous blockchains and layer-2 networks. Multi-chain dApps exist as isolated instances of smart contracts deployed across various networks, which can lead to fragmented liquidity and decreased capital efficiency, but offer benefits such as reduced risks from cross-chain bridge vulnerabilities. Cross-chain dApps, on the other hand, allow developers to create unified applications that operate across multiple blockchains, leveraging the unique advantages of each network to enhance interoperability and capital efficiency. This cross-chain functionality is crucial for a more interconnected Web3 ecosystem, exemplified by protocols like the Cross-Chain Interoperability Protocol (CCIP) and the Chainlink Network, which facilitate communication and token transfers across different blockchains. These advancements aim to create a seamless user experience akin to Web2, while maintaining the core principles of blockchain technology such as immutability and trust-minimization.