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Bridge (Cross Chain Liquidity Between EVM Networks)

A bridge lets users move liquidity between independent blockchains that do not share native state. In practice, bridges are the interoperability layer that allows assets, collateral, and trading capital to move to ecosystems with better liquidity, lower fees, or different DeFi opportunities. Without bridges, users often rely on centralized exchanges and repeated off-ramp/on-ramp steps each time they switch networks. This page introduces bridge mechanics in general, then focuses examples on Ethereum and Avalanche so users can clearly follow how funds move and what gets locked, minted, burned, and unlocked.

Why this matters​

Liquidity is fragmented across chains. If your funds are on one network, you cannot directly use them on another without bridging first. A bridge moves value while preserving supply accounting.

At a high level:

  • Source side: assets are locked or burned
  • Destination side: equivalent value is minted or released

What to set up before bridging​

Use this checklist before your first transfer.

  1. Wallet
    • MetaMask (or another EVM wallet)
  2. Networks in wallet
    • Ethereum Mainnet
    • Avalanche C-Chain
  3. Gas on both sides
    • ETH for Ethereum transactions
    • AVAX for Avalanche transactions
  4. Bridge interface
  5. Token details
    • Confirm token contract and expected destination representation
    • Add destination token to wallet if balance does not auto-display

How the bridge functions (Ethereum to Avalanche)​

This direction is common when users want lower fees and Avalanche DeFi access.

User transaction sequence​

  1. Connect wallet to the bridge UI.
  2. Set source as Ethereum and destination as Avalanche C-Chain.
  3. Select token and amount (example: USDC).
  4. Approve token allowance (ERC-20 approve transaction).
  5. Submit bridge transfer (bridge transaction).
  6. Wait for finality and switch wallet to Avalanche to view funds.

Protocol-level flow​

  1. Your token is sent to a bridge vault or contract on Ethereum.
  2. That source-side amount is locked and no longer spendable by you.
  3. Bridge validators or relayers attest to the event.
  4. Destination bridge logic on Avalanche mints or releases equivalent value.

What is locked and what is received​

  • Locked on Ethereum: original source asset
  • Received on Avalanche: bridged representation or equivalent value
  • Supply rule: destination issued amount is backed by source locked amount

End-to-end example: 1,000 USDC round trip​

Stage 1: Initial state​

  • Ethereum wallet: 1,000 USDC
  • Avalanche wallet: 0 bridged USDC

Stage 2: Bridge to Avalanche​

  • Approve 1,000 USDC spend on Ethereum
  • Submit bridge transfer for 1,000 USDC
  • 1,000 USDC is locked in Ethereum bridge vault
  • Equivalent bridged USDC appears on Avalanche

Stage 3: Use liquidity on Avalanche​

  • Trade, provide LP, lend, or use as collateral in Avalanche protocols
  • Keep AVAX for gas for all Avalanche-side actions

Stage 4: Bridge back to Ethereum​

  • Submit return transfer from Avalanche
  • Bridged USDC on Avalanche is burned or locked
  • Original USDC is unlocked from Ethereum vault and returned

Fees, timing, and practical behavior​

Users should expect:

  • Two source-side transactions for ERC-20 routes (approve then bridge)
  • Gas costs across both ecosystems over the full cycle
  • Bridge or relayer fee depending on route
  • Finality delay before destination funds are spendable

For first-time routes, send a small test amount before large transfers.

Common failure points to avoid​

  • Wrong network selected in wallet
  • Wrong token contract or symbol on destination
  • Insufficient ETH or AVAX for gas
  • Using unofficial bridge URLs
  • Assuming similarly named assets are equivalent

Bridge vs ICTT on Watr​

This page explains Ethereum to Avalanche bridge mechanics for liquidity movement.

For Watr-specific transfer between Fuji and Watr testnet, use Interchain Token Transfer (ICTT).

References​