Building Multi-Chain Apps

Multi-chain development requires new patterns: deploy contracts on multiple chains, handle cross-chain messages, and manage state consistency. Frameworks like Hyperlane and Wormhole provide SDKs for cross-chain messaging. Key considerations: which chain for which function (compute-heavy on an L2, settlement on Ethereum), handling message failures and retries, managing cross-chain security (the weakest link determines overall security), and user experience (abstracting chain selection from users via chain abstraction protocols like Socket).