Introduction to Cross-Chain Bridges

Blockchains are isolated by design. Ethereum cannot natively read Solana balances, and Arbitrum does not automatically know what happened on Base. That isolation is a security feature — each network enforces its own rules without trusting foreign validators — but it also fragments liquidity and users.

Bridges power multichain DeFi, NFT portability, and governance across ecosystems. They are also among the largest honeypots in crypto — billions in locked value sitting behind complex validation logic that attackers probe constantly.

This course walks through how bridges work, where they fail, and how to use them without treating speed as a substitute for security.