A protocol that connects different blockchain networks, enabling cross-chain transfers.
Detailed Explanation
A blockchain bridge is a protocol or platform that enables the transfer of assets and data between two otherwise incompatible blockchain networks. Bridges solve the interoperability problem — blockchains are typically isolated systems that can't communicate with each other natively. When you use a bridge, your assets on the source chain are typically locked in a smart contract while equivalent wrapped tokens are minted on the destination chain. Bridges can be trusted (centralized, relying on a specific entity) or trustless (decentralized, relying on smart contracts and cryptographic proofs).
Why It Matters
As the crypto ecosystem expands across multiple blockchains, bridges are essential infrastructure for moving value between networks. They allow users to access DeFi opportunities on different chains, reduce fragmentation of liquidity, and enable a multi-chain future. However, bridges have been major targets for exploits, making security a critical consideration.
Real-World Example
If you hold ETH on Ethereum but want to use a DeFi protocol on Polygon, you would use a bridge like the Polygon PoS Bridge. You deposit your ETH into the bridge contract on Ethereum, and an equivalent amount of wrapped ETH appears in your wallet on Polygon, typically within a few minutes.