Crypto Definitions

What Is a Crypto Bridge and How Do Token Bridges Work?

By Ben Simpson, Founder of Collective Shift. Reviewed by Matt Willemsen, Director of Research. Updated 5 November 2026.

Collective Shift guide cover: What is a crypto bridge?

Short answer: A crypto bridge is a tool that moves tokens or data from one blockchain to another, such as from Ethereum to a layer 2 network. Most bridges lock your tokens on the first chain and issue matching tokens on the second. Bridges are useful but have suffered some of the largest hacks in crypto, so design matters.

Key points

Bridges connect blockchains that cannot talk to each other directly.
Lock and mint bridges hold the original tokens and issue wrapped versions.
Liquidity bridges swap your tokens for native tokens already on the other chain.
Bridge contracts hold large pools of funds, which makes them a frequent hack target.

How a token bridge works

In a lock and mint bridge, you send tokens to a contract on the source chain, and the bridge mints the same amount of a wrapped token on the destination chain. Moving back burns the wrapped token and releases the original. Official layer 2 bridges work this way, with withdrawals back to Ethereum sometimes taking days on some networks.

Types of bridges

Type	How it works	Main trade off
Lock and mint	Locks tokens, mints wrapped copies	Backing pool is a large target
Liquidity network	Swaps for native tokens on the other chain	Depends on pool depth and fees
Native rollup bridge	Built into a layer 2 and secured by Ethereum	Slower withdrawals on some networks
Trusted or custodial	A company or group of signers controls funds	Relies on those signers

Why bridges get hacked

A bridge contract can end up holding a large share of a token’s supply, and the security of the whole system rests on its code and the people or software that approve transfers. Attacks on bridges such as Ronin and Wormhole in 2022 were among the largest in crypto history.

Safer bridging habits

Use the official bridge for a network where one exists.
Type the address yourself or use bookmarks, as fake bridge sites are common.
Send a small test amount first.
Check that the token you receive is the one the network’s apps use.

Our step by step bridging tutorial walks through the process.

Bridges vs centralised exchanges

Another way to move value between networks is to deposit on a centralised exchange and withdraw on a different network. This avoids bridge contracts but adds exchange custody and identity checks. Each route suits different needs, as covered in our crypto exchange definition.

Frequently asked questions

Is bridging crypto safe?

It carries real risk. Official and well established bridges reduce it, but no bridge is risk free.

Why does bridging back to Ethereum take so long?

Some layer 2 networks use a challenge period of about a week before withdrawals finalise, which protects against fraud.

What is an ETH bridge?

It is a bridge that moves ether between Ethereum and another chain, often a layer 2 network.

Do bridges charge fees?

Yes. You pay gas on both chains and often a bridge fee or spread.

This guide is general education only and is not personal financial advice. Collective Shift Pty Ltd, ABN 78 650 977 325.

Written by Ben Simpson, Founder of Collective Shift, and reviewed by Matt Willemsen, Director of Research. Published 5 November 2026. Updated 5 November 2026.