Migrating assets between Layer 2 networks shouldn’t come with surprise costs. A custom migration fee lets you control exactly what users pay instead of relying on volatile gas estimates.
Start in your bridge or rollup contract: add a
setMigrationFee(uint256 _fee)
function guarded by
onlyOwner
. Store the value in a public state variable and call it in your migration logic, adding
the fee to the transfer amount or deducting it from the bridged token.
Test on a testnet first, then verify the fee on-chain before mainnet. A fixed, transparent fee builds trust — users know the cost before they bridge.