Blockchain bridge
A blockchain bridge is a service that moves tokens from one network to another, usually by locking them on the source chain and issuing an equivalent on the destination chain.
How it works
Blockchains cannot see each other directly. The most common design is lock and mint: you send, say, USDC to the bridge contract on chain A, and you receive the same amount of tokens on chain B. Going back burns them on B and releases the original on A. Some bridges use liquidity pools instead and simply pay you from a reserve on the other chain.
Bridges let you use apps and lower fees on other networks, for example moving from Ethereum to a layer 2. A transfer can take anything from a minute to several days, depending on how the bridge works.
Bridges are among the most hacked parts of crypto because their contracts hold huge sums. In 2022 several bridge hacks cost hundreds of millions of dollars each. If a bridge is hacked, the tokens it issued can lose their value.
You bridge 500 USDC from Ethereum to a layer 2. Ethereum gas is $4 and the bridge fee is 0.05% ($0.25). You receive ~499.75 USDC on the new network, where each transaction then costs cents. Withdrawing back through the layer 2's official bridge can take up to 7 days.
A common mistake is finding a bridge through a search ad and landing on a phishing site that asks you to approve all your tokens. Use only official links from the network's documentation, check which network and token you will receive, and send a small test amount first.
Questions and answers
What is a bridge in crypto in simple terms?
It is a way to move tokens from one blockchain to another. Usually the original is locked and you get an equivalent on the new network.
Are crypto bridges safe?
They are a high-risk area: big balances make them frequent hacking targets. Use well-known official bridges and do not hold large amounts of bridged tokens for long.
What if my tokens did not arrive after bridging?
Check the transaction in the block explorers of both networks and the status on the bridge's official site. Some transfers take a long time or need a separate claim step on the destination chain.
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Updated: 2026-10-19