Module 4 · Lesson 29 of 45

Bridges & moving tokens across chains

⏱ 6 min read ● Intermediate Module 4 · Advanced concepts

A common beginner expectation: "I'll just swap my Ethereum token for a Solana token on this DEX." You can't — at least not on a single ordinary DEX. Understanding why introduces bridges.

Why one DEX can't go cross-chain

A DEX and its pools live on a single blockchain. Your Ethereum wallet and a Solana DEX don't share a ledger, so no pool holds both. To move value between chains you need separate infrastructure: a bridge.

Lock-and-mint, in plain terms

The classic bridge design works like a coat check:

  1. You lock your token in the bridge's contract on the source chain.
  2. The bridge mints an equivalent wrapped token on the destination chain.
  3. To return, you burn the wrapped token and the bridge releases your original.

The wrapped token is a stand-in, redeemable 1:1 for the real asset locked on the other side.

How to bridge safely

  • Use an official, reputable bridge — reach it via a verified link, never an ad or DM.
  • Send a small test amount first, confirm it arrives, then bridge the rest.
  • Double-check the destination network and address — cross-chain mistakes are unforgiving.
  • Bring gas — you'll need the destination chain's native coin to do anything once you arrive (Lesson 10).
  • Consider a cross-chain aggregator, which finds a route and often abstracts the steps.

An honest warning

Bridges are powerful, but they've also been the site of some of the largest hacks in crypto history. That risk is serious enough to deserve its own lesson — which is exactly what comes next.

Key terms
BridgeInfrastructure that moves value between two blockchains.
Lock-and-mintLocking an asset on one chain and minting a wrapped version on another.
Wrapped tokenA stand-in token redeemable 1:1 for the asset locked on the source chain.
Cross-chain aggregatorA tool that finds and abstracts a multi-step bridging route.
!Common mistakes
  • Expecting a single DEX to swap a token from one chain for a token on another.
  • Bridging a large amount without a small test transfer first.
  • Arriving on a new chain with no native coin for gas, leaving the bridged funds stuck.
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