A blockchain bridge is a protocol that enables the transfer of assets or data between two separate blockchain networks that would otherwise be unable to communicate. Because blockchains like Bitcoin, Ethereum, Solana, and BNB Chain each operate on their own isolated ledger with their own rules, bridges are essential infrastructure for the multi-chain crypto ecosystem — allowing users and liquidity to move freely between networks rather than being locked to a single chain.
How bridges work: most bridges use a lock-and-mint mechanism — tokens are locked in a smart contract on the source chain, and a wrapped equivalent is minted on the destination chain (e.g. Wrapped Bitcoin / WBTC on Ethereum represents BTC locked by a custodian). Burn-and-mint bridges destroy tokens on the source chain and mint new ones on the destination. Liquidity bridges (like Stargate, built on LayerZero) use pools on both sides for native-to-native transfers without wrapping. Bridges are simultaneously critical infrastructure and crypto’s biggest security risk: bridge hacks have resulted in some of the largest losses in crypto history. The Ronin Bridge (Axie Infinity) lost $625M in 2022; the Wormhole bridge lost $320M. Security best practices: use only audited, battle-tested bridges; minimise time spent in bridge transit; prefer native bridging where available over third-party bridges.
Example: A user wants to use their ETH holdings in a Solana DeFi protocol. They use a bridge to transfer ETH to Solana, receiving wETH (wrapped ETH on Solana), which they can then deploy in Solana-based lending protocols.
Learn more: Ethereum.org — Blockchain Bridges
