Bridge vs swap: which one do you need? Same coin, new chain, or a different coin altogether. And what each one asks you to trust.

01Bridge or swap: the one-line difference

A bridge changes the chain and keeps the asset. A swap changes the asset, and can change the chain too.

Why do bridges exist at all? Because blockchains "cannot natively communicate, and tokens cannot move freely between blockchains". Something has to carry the value across.

• ETH on Ethereum to ETH on Arbitrum: either works.
• ETH on Ethereum to SOL on Solana: a swap, or a bridge and then a swap.
• BTC to use in Ethereum apps: a bridge or a wrap gives you a wrapped copy; a swap gives you ETH or a token instead, like converting BTC to ETH in one order.

The main guide on how to swap crypto covers the rest of the trip.

02How a bridge works: lock, burn, or swap with a pool

ethereum.org names three ways to move value between chains:

1. Lock and mint. "Lock assets on the source chain and mint assets on the destination chain."
2. Burn and mint. Burn on the source chain, mint on the destination chain.
3. Swap with another party. "Swap assets on the source chain for assets on the destination chain with another party."

The third one is, in plain words, a swap: you get the other chain's real asset from someone who holds it. The oldest version is the atomic swap, where two people exchange coins "without having to trust a third party".

03Wrapped vs native: what you actually hold afterwards

Lock and mint leaves you holding a copy. That copy has a name: a wrapped token.

ethereum.org is blunt about WBTC: "it's an Ethereum version of Bitcoin and not the original asset on the Bitcoin blockchain". On 3 November 2026, Etherscan showed 116,132 WBTC in supply. That many bitcoin sit with whoever backs the token.

Even wrapped ether comes in versions. Besides the main one, ethereum.org warns that other wrapped ETH tokens "may behave differently or have different security properties".

Bottom line: a wrapped coin is a receipt. It's worth what the vault behind it still holds.

04What each route asks you to trust

Every route asks you to trust someone. The real question is who, and for how long.

ethereum.org splits bridges in two. Trusted bridges "are externally verified" by a group of signers or an oracle network. Trustless bridges "do not add new trust assumptions (in addition to the blockchains)", though they still run on code. And it lists four risks:

• Smart contract risk: "the risk of a bug in the code that can cause user funds to be lost".
• Custodial risk: "bridge operators can collude to steal the users' funds".
• Censorship risk: operators can stop your transfer.
• Technology risk: bugs, human error and attacks can disrupt it.

Here's the line most guides miss. Use a bridge once and keep the wrapped coin, and you trust its vault for as long as you hold it. A swap that pays the chain's own coin asks you to trust the service from your deposit to your payout, and then it's over.

05What has gone wrong: four bridge hacks, from the record

ethereum.org says it outright: "Bridges account for the top three biggest hacks in DeFi". Here are four, from government and research records.

1. Ronin, March 2022. An FBI affidavit filed with the DOJ says "over $600 million in Ether was stolen", and that the FBI found the Lazarus Group responsible.
2. Wormhole. ethereum.org records "120k wETH ($325 million USD)" stolen.
3. Nomad, August 2022. The attacker "stole around $190 million worth of tokens". One man now faces charges over his alleged share: four exploit transactions taking WBTC and WETH worth about $2.89 million.
4. Harmony's Horizon bridge. The same FBI affidavit records "over $100 million of virtual assets" stolen, also attributed to Lazarus.

In the first seven months of 2022 alone, bridge attacks cost $2 billion, 69% of all DeFi attack losses in that period. Research on 2023 found bridges "remain vulnerable to various attacks".

Notice the pattern: every target was the pool of locked coins, the exact thing a wrapped token is a claim on.

06Fees and time: what a cross-chain move costs

A bridge sends you more than one bill. A swap shows one number.

With a bridge you pay gas on the sending chain, the bridge's fee, and often gas on the new chain, which means holding a coin there you may not have yet. Here's what our own desk quoted for the same coin across chains, every fee inside:

300 USDC on Ethereum landed as 296.82 USDC on Solana. 0.2 ETH on Ethereum landed as 0.1980 ETH on Arbitrum. Why the Tron routes cost more is in TRC-20 vs ERC-20.

Time has one big exception. Leaving an optimistic rollup through its own bridge means waiting for the challenge period, "lasting roughly seven days". ethereum.org's way around it: a liquidity provider who pays you now "in exchange for a fee". That's a swap, too. And any quoted amount can move a little before your trade, as crypto slippage explains.

07Bridge or swap? Four questions

Three taps, and the answer comes with what you'd be trusting:

1. What do you hold, on which network?
2. What do you want, on which network? A different coin means a swap.
3. Do you need the chain's own coin? For gas, or for an exchange that only takes the native one, a swap pays exactly that.
4. How long will you hold it? The longer you keep a wrapped copy, the longer you trust its vault.

08What our desk does

Same coin on a new network? Try USDT on Tron to USDT on Ethereum. A new coin on a new chain? SOL to ETH is one order. If the coin you receive needs a memo, our guide to crypto memos has every rule. Start on our swap with no ID.