What Are Cross-Chain Bridges?

Learn the fundamentals of cross-chain bridges, how they work, and why they're essential for DeFi.

Bridge Basics5 min readBeginner

What Are Cross-Chain Bridges?

Learn the fundamentals of cross-chain bridges, how they work, and why they're essential for DeFi.

What is a Bridge?

When looking for cross-chain bridges, A cross-chain bridge is a protocol that allows you to transfer cryptocurrency tokens from one blockchain to another. Think of it as a secure tunnel between different blockchain networks.

For example, if you have USDC on Ethereum but want to use it on Polygon for lower fees, you'd use a bridge to move your USDC from Ethereum to Polygon.

Bridge Visualization

Bridge Visualization

⛓️
ethereum
🌉
⛓️
polygon
🌉
⛓️
arbitrum
Supported Tokens:
USDCETHWBTC

How Bridges Work

When looking for cross-chain bridges, Bridges work by locking your tokens on the source chain and minting equivalent tokens on the destination chain. Here's the basic process:

  1. **Lock**: You send tokens to the bridge contract on the source chain
  2. **Verify**: The bridge verifies your transaction
  3. **Mint**: The bridge mints equivalent tokens on the destination chain
  4. **Receive**: You receive the tokens in your wallet on the new chain
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    Types of Bridges

    Types of Bridges

    Bridge / FeatureAdvantagesDisadvantagesExamples

    Lock & Mint Bridges

    Lock tokens on source chain, mint on destination

    Simple to understandWidely supported
    Requires trust in bridgeCentralization risk
    MultichainPortal Bridge

    Liquidity Bridges

    Use liquidity pools on both chains for instant swaps

    Fast transfersNo minting required
    Limited by liquiditySlippage possible
    Hop ProtocolAcross

    Optimistic Bridges

    Assume transactions are valid, challenge if not

    More decentralizedLower costs
    Longer withdrawal timesComplex disputes
    Arbitrum BridgeOptimism Bridge
    By Bridge Optimizer Team
    Last updated: 1/15/2024
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