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Bridge Kit lets you collect a transfer fee from your end users. You can set this fee globally for the kit or on each bridge call. Per-call fees override the global fee. You can set a flat or dynamic fee based on the parameters.
Note: If you use this feature, Circle keeps 10% of the transfer fee you collect from your end users.

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Set fee per bridge call

This example configures your bridge call to collect a fee of 1.50 USDC for a specific bridge transfer:
TypeScript
// Transfer 1 USDC
const result = await kit.bridge({
  from: { adapter, chain: "Ethereum" },
  to: { adapter, chain: "Base" },
  amount: "1.00",
  // Collect a fee of 1.50 USDC on this transfer and override the global fee, if set
  config: {
    customFee: {
      value: "1.50",
      recipientAddress: "YOUR_WALLET_ADDRESS",
    },
  },
});

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Set fee globally

This example configures your global setup to collect a fee of 1 USDC on transfers from Ethereum and 1.50 USDC on transfers from other blockchains:
TypeScript
import { Blockchain } from "@circle-fin/bridge-kit";
const kit = new BridgeKit();

kit.setCustomFeePolicy({
  calculateFee: (params) => {
    // Charge 1 USDC if the source chain is Ethereum and 1.50 USDC on other blockchains
    return params.source.chain.chain == Blockchain.Ethereum ? "1.00" : "1.50";
  },
  resolveFeeRecipientAddress: (feePayoutChain, params) => {
    // Change the recipient address if the source chain is Ethereum
    return params.source.chain.chain == Blockchain.Ethereum
      ? "YOUR_WALLET_ADDRESS"
      : "YOUR_OTHER_WALLET_ADDRESS";
  },
});