What Is a Bridge and When Do You Need One

Different blockchains are separate systems. A bridge moves value between them.

How it works

The most common design locks your asset on the source chain and issues a representation of it on the destination chain.

The representation is backed by the locked original. Returning it burns the representation and releases the original.

Other designs use liquidity pools on both sides, where you deposit into one and withdraw from the other.

Why bridges have been dangerous

Bridges hold large balances and combine several trust assumptions at once. They have been the single most exploited category of infrastructure in crypto, with individual incidents costing hundreds of millions.

The reason is structural: a bridge is a large pot of assets secured by a mechanism that is newer and less battle-tested than the chains it connects.

The alternative most people should use

Withdraw to an exchange that supports both networks, then withdraw from the exchange to the destination.

Cost: two withdrawal fees, published in advance.

Time: usually minutes.

Bridge risk: none, because no bridge is involved.

For most amounts this is both cheaper and safer than any bridge, and it is the route almost nobody considers because the bridge interface is what appears when you search for how to move between chains.

Venues publishing which networks they support per asset, such as exchanges that support direct bank transfer, make this straightforward to price before moving anything.

When you actually need a bridge

The asset is not listed on any venue you can use.

You need to stay in self-custody throughout for a specific reason.

The amount is small enough that two fixed withdrawal fees exceed the bridge cost.

If you do use one

Prefer the network’s own canonical bridge over a third party. Slower and considerably more trust-minimised.

Check what you receive. Some bridges deliver a wrapped version that trades below the native asset, which is a cost that appears later.

Compare the amount received, not the quoted fee. Bridges price differently and only the final number is comparable.

Send a test amount first if the route is unfamiliar.

The summary for a beginner

You probably do not need a bridge.

If you are buying, holding, and occasionally moving between a venue and your own wallet, the exchange handles the network choice and no bridging is involved.

Bridges become relevant when you start using applications on multiple chains, and by then the trade-offs above are worth reading properly rather than accepting whatever the interface suggests.