What is a blockchain bridge? A cross-chain transfer example

A blockchain bridge enables assets or messages to move between separate blockchains. An action on the source network is verified through the bridge’s mechanism before a corresponding action occurs on the destination. Switching the network displayed in a wallet does not move a balance.

Does the original token move?

That depends on the design. Lock-and-mint systems hold an asset in a source contract and issue a representation on the destination. Burn-and-mint systems remove source tokens from circulation before issuing destination tokens. Other arrangements pay users from liquidity already available on the receiving chain. Ethereum’s bridge documentation covers messages and contract calls as well as asset transfers.

Example

Alex holds 100 tokens on network A. In a hypothetical bridge, 100 tokens are locked on A and 100 representative tokens are issued on B, with fees excluded for clarity. If locking succeeds but the destination message has not executed, Alex may still have a zero balance on B. A successful source transaction alone does not establish delivery.

A representative token can share a familiar name while using a different network and contract address. Redemption depends on the relevant bridge’s release or delivery rules. Assess both networks, the bridge contracts and message verification together; a canonical label is not a guarantee against losses.

A destination asset may be a wrapped token without sharing the source asset’s contract. The crypto bridge guide explains how to match networks and token addresses before transferring.