Multichain: What is a Bridge in Crypto? Bridging Explained

You have just bought some Ethereum and it is sitting in your wallet. Then you spot a new decentralised finance (DeFi) app or a blockchain game that everyone is using.

There is a catch. The new app runs on a different blockchain, such as Solana or Arbitrum. Because each blockchain is its own network with its own set of rules, your Ethereum cannot simply jump across. It is stuck on its home chain.

To use that new app, you need a way to move the value of your Ethereum across the gap. That is what a crypto bridge is designed to do.

What is a blockchain bridge?

It can help to imagine blockchains as separate islands. The Bitcoin island has its own currency, rules and economy. The Ethereum island is another place with a different currency and coding language.

For years, these islands could not talk to each other. A boat leaving Bitcoin island had nowhere to dock on Ethereum island.

A blockchain bridge acts like a ferry or a tunnel between islands. It creates a communication channel so users can transfer tokens, data and even smart contract instructions from one chain to another.

Without bridges, the crypto world would stay broken into small, separate pools of liquidity. You would need to sell your Bitcoin for cash, then spend that cash to buy Ethereum every time you wanted to change networks. Bridges make this smoother and keep value inside the crypto system rather than bouncing through your bank account.

How bridges work in practice

Behind the scenes, bridge technology is complicated. From a user point of view, though, things have improved a lot. As of 2026, most people use simple, intent-based interfaces and do not need to manage multi-step transactions themselves.

Under the hood, most bridges still rely on three main models to move value.

1. The Lock and Mint model

The most traditional approach is called the Lock and Mint model. When you send a token across this type of bridge, the actual coin does not move to the other chain.

• Locking: You deposit your asset (for example, Bitcoin) into a smart contract on the source chain. This works like a secure vault.
• Verifying: The bridge protocol checks that the funds are locked and cannot be spent anywhere else.
• Minting: The bridge then mints an equal amount of a “wrapped” token on the destination chain.

If you deposited Bitcoin, you might receive Wrapped Bitcoin (wBTC) on Ethereum. This wrapped token is basically an IOU. It represents a claim on the original Bitcoin sitting in the vault.

If you want to go back, the wrapped token is burned (destroyed) and your original Bitcoin is released from the smart contract.

Note: While wBTC is a well-known example of this model, it specifically relies on centralised custodians to manage the locked Bitcoin, which adds an additional trust layer. Not all Lock and Mint bridges use this centralised approach. Some use decentralised smart contracts or validator networks instead.

2. The Burn and Mint model

A newer and generally safer approach, used heavily by stablecoin issuers such as Circle, is the Burn and Mint model.

Here, funds are not parked in a central vault. Instead, the token on the source chain is permanently burned. Then the issuer automatically mints a brand new, native token on the destination chain.

Because there is no giant pool of locked assets, this model reduces the “honeypot” value for hackers. There is less incentive and less opportunity for a single, huge exploit.

3. Intent-based bridges (the modern standard)

The most important shift in bridge technology in recent years is intent-based architecture. Instead of asking users to build complex multi-chain transactions, intent-based bridges let you simply state the result you want. Some bridge aggregators now incorporate intent-based routing automatically.

For example, you might tell the protocol: “Send 100 USDC from Ethereum to Arbitrum.”

Behind the scenes, a network of specialised agents called solvers competes to fill your request. These solvers use their own capital to send funds to you on the destination chain straight away, often within seconds. They are reimbursed later by the protocol once everything is reconciled on-chain.

This approach is usually faster and cheaper than older methods, and it feels far more like a normal transfer.

Why use a bridge?

Bridges are not only about shifting money from A to B. They are mainly about getting access to better tools, cheaper fees and different apps on other networks.

Most people bridge for three main reasons.

Lower transaction fees

Some major blockchains, including Ethereum, can be expensive when they are busy. Gas fees can spike during popular NFT mints, token launches or trading rushes.

To avoid this, users often bridge their assets to Layer 2 networks or alternative chains where fees are much lower. This matters for smaller trades, regular DeFi activity or anyone who does not want to pay $20 just to move a token.

Speed

Traders often bridge to high-speed networks so they can enter and exit positions quickly. The same applies to derivatives and on-chain arbitrage.

Gamers do something similar. They bridge to networks that can handle thousands of in-game actions without delays, so gameplay feels closer to using a normal online game rather than waiting for slow confirmations.

Access to exclusive apps

Many decentralised applications (dApps) only run on one or two blockchains. Some can be on a single Layer 2 or side-chain for cost and performance reasons.

If you want to play a game that only exists on a specific side-chain, or you want to use a lending platform built on Avalanche, you need to get your assets onto that network. A bridge is the tool that gets you there.

Real-life examples

Here are some common bridge-related projects and ideas you are likely to see.

Wrapped Bitcoin (wBTC)

Wrapped Bitcoin is a textbook Lock and Mint example. The Bitcoin network does not natively support complex smart contracts, so it is hard to use BTC directly in most DeFi apps.

By bridging Bitcoin to Ethereum, users receive wBTC, which is an ERC‑20 token that works smoothly with Ethereum’s DeFi ecosystem. This lets people use their Bitcoin holdings in Ethereum-based lending platforms, decentralised exchanges and yield protocols.

Circle’s Cross-Chain Transfer Protocol (CCTP)

Circle’s Cross-Chain Transfer Protocol (CCTP) uses the Burn and Mint model to move USDC, a US dollar stablecoin, between blockchains.

Instead of receiving a wrapped version of USDC, the user receives native USDC on the destination chain. The original tokens are burned on the source chain, and the new ones are minted on the other side.

The launch of CCTP V2 in 2025 added a feature called “Hooks”. This lets users transfer funds and trigger another action, such as a swap or a deposit into a DeFi pool, all in a single step.

Bridge aggregators

Choosing a single bridge manually can be confusing, especially with dozens of options and networks.

To simplify this, many people now use bridge aggregators such as Li.Fi, Bungee or Jumper. These platforms compare routes across many bridges at once. They then choose the option that best balances speed, cost and security for your specific transfer.

Think of them like travel comparison sites. Instead of you checking every airline and every route, the aggregator does the searching and shows you a simple result.

Risks and red flags

Bridges can be very useful, but they also come with extra risk. In fact, bridge-related hacks have made up a large share of total crypto losses in past years. In terms of crypto hacks, Q1 2025 was unfortunately the worst quarter on record. with Immunefi estimating US$1.64 billion lost.

Before you move significant funds, it pays to understand what can go wrong.

The honeypot risk

In the Lock and Mint model, the bridge smart contract can hold a large pool of cryptocurrency. This creates a single point of failure.

If an attacker finds a bug in the contract and drains the vault, the wrapped tokens on the other chain become worthless. There is no longer any real asset backing them. Even if you still hold the wrapped tokens in your wallet, there is nothing left to redeem.

De-pegging

Wrapped tokens, or any pegged asset, are designed to track the value of the original at a 1:1 rate. One wBTC should always be worth one BTC. One bridged USDC should equal one native USDC.

If a bridge loses user trust or suffers a security event, the market may start valuing the wrapped token at less than the original. This is called “de-pegging”. In a serious crisis, the discount can be large, and those losses may never fully recover.

Smart contract vulnerabilities

Bridges are entirely controlled by code. Deposits, withdrawals and cross-chain messages all rely on smart contracts and off-chain relayers.

If the code that manages these actions has a flaw, users can lose funds. Bugs can lead to stuck transfers, partial losses or complete drains.

Before using a bridge, it is sensible to check a few things:

• Has the protocol been audited by well-known security firms?
• How long has it been live without major incidents?
• Is the team public and responsive to issues?
• Does it have bug bounties or formal security programs?

No audit is a guarantee, but a lack of audits and a short track record should be a clear warning sign.

The future of multichain

The crypto industry is steadily moving towards a future where “bridging” disappears into the background. This idea is often called chain abstraction.

In a fully abstracted world, you would simply open an app and use it. Your wallet or the protocol would handle any required cross-chain transfers in the background. You would not need to know, or care, which blockchain you are on, in the same way you do not think about which data centre is holding your email.

Developments like intent-based architecture and advanced bridge aggregators are important steps in that direction. They reduce friction and hide complexity without removing user choice.

Until we get to that point, understanding how bridges work, and what risks they carry, remains an important part of using crypto safely. Especially if you are moving larger amounts or using newer networks, a basic grasp of bridge mechanics can help you avoid nasty surprises.