Bridge

A bridge is a connection that lets you move tokens or NFTs to another blockchain. This is necessary because blockchains normally don't communicate directly with each other.

What is a bridge?

A blockchain is a digital network that keeps track of transactions. Each network has its own rules and tokens. That's why you can't simply use tokens from Ethereum on Polygon or Solana.

A bridge helps move tokens between networks. Often, your original tokens are first locked on one blockchain. Then you receive a wrapped version on the other blockchain. It represents the value of the original token.

Bridges can be managed by a centralized party or operate using smart contracts and validators. Smart contracts are programs that automatically carry out agreements. In some systems, validators check whether the transfer is valid.

An example of a bridge

Say you have tokens on Ethereum and want to use them on Polygon. You send the tokens to Polygon through a bridge. The bridge locks the original tokens on Ethereum and usually gives you a wrapped version on Polygon.

Want to move them back to Ethereum? The wrapped version is destroyed, and then your original tokens are released. You pay transaction fees for these steps, often called gas fees.

Why are bridges important in crypto?

Bridges give you access to applications on different blockchains. For example, they can help you use tokens on a network with different fees or features. That's why a bridge may come up in news about new blockchain projects, DeFi, or NFTs.

Bridges are also a key security concern. A lot of tokens may be locked in a bridge. Vulnerabilities in smart contracts or poorly secured multisig systems can therefore make bridges attractive targets for hackers.

Using a bridge doesn't always mean you have the exact same token on the new network. Often, you use a wrapped token there. Also, always check that you've chosen the right bridge and destination network, because bridge transactions can be technically complicated.