Skip to main content

​
Overview

The PolygonBridgeFacet enables bridging of ETH and ERC20 tokens from Ethereum mainnet to Polygon PoS (Proof of Stake) using the official Polygon bridge infrastructure.

​
Contract Interface

​
Functions

​
startBridgeTokensViaPolygonBridge

Bridges tokens from Ethereum to Polygon PoS. 
function startBridgeTokensViaPolygonBridge(
  BridgeData _bridgeData
) external payable
​
_bridgeData
BridgeData
Standard bridge data containing transaction details

​
swapAndStartBridgeTokensViaPolygonBridge

Performs a token swap on Ethereum before bridging to Polygon. 
function swapAndStartBridgeTokensViaPolygonBridge(
  BridgeData _bridgeData,
  SwapData[] _swapData
) external payable
​
_bridgeData
BridgeData
Standard bridge data
​
_swapData
SwapData[]
Array of swap operations to execute before bridging

​
Usage Example

​
Bridging ETH to Polygon

import { PolygonBridgeFacet } from '@lifi/contract-types';

const polygonFacet = PolygonBridgeFacet__factory.connect(facetAddress, signer);

const bridgeData = {
  transactionId: ethers.utils.randomBytes(32),
  bridge: 'polygon',
  integrator: 'my-dapp',
  referrer: '0x0000000000000000000000000000000000000000',
  sendingAssetId: '0x0000000000000000000000000000000000000000', // Native ETH
  receiver: await signer.getAddress(),
  minAmount: ethers.utils.parseEther('1'),
  destinationChainId: 137, // Polygon PoS
  hasSourceSwaps: false,
  hasDestinationCall: false
};

const tx = await polygonFacet.startBridgeTokensViaPolygonBridge(
  bridgeData,
  { value: bridgeData.minAmount }
);

await tx.wait();

console.log('Bridging initiated. Tokens will arrive on Polygon in ~7-8 minutes.');

​
Bridging ERC20 Tokens

const bridgeData = {
  transactionId: ethers.utils.randomBytes(32),
  bridge: 'polygon',
  integrator: 'my-dapp',
  referrer: '0x0000000000000000000000000000000000000000',
  sendingAssetId: '0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48', // USDC on Ethereum
  receiver: await signer.getAddress(),
  minAmount: ethers.utils.parseUnits('1000', 6),
  destinationChainId: 137,
  hasSourceSwaps: false,
  hasDestinationCall: false
};

// Approve USDC first
const usdc = new ethers.Contract(
  bridgeData.sendingAssetId,
  ['function approve(address spender, uint256 amount) returns (bool)'],
  signer
);

await usdc.approve(polygonFacet.address, bridgeData.minAmount);

// Bridge tokens
const tx = await polygonFacet.startBridgeTokensViaPolygonBridge(
  bridgeData,
  { value: 0 }
);

await tx.wait();

​
Swap and Bridge

const swapData = [{
  callTo: uniswapRouter,
  approveTo: uniswapRouter,
  sendingAssetId: daiAddress,
  receivingAssetId: usdcAddress,
  fromAmount: ethers.utils.parseUnits('1000', 18),
  callData: swapCalldata,
  requiresDeposit: true
}];

const bridgeData = {
  transactionId: ethers.utils.randomBytes(32),
  bridge: 'polygon',
  integrator: 'my-dapp',
  referrer: '0x0000000000000000000000000000000000000000',
  sendingAssetId: usdcAddress, // Will receive USDC after swap
  receiver: await signer.getAddress(),
  minAmount: ethers.utils.parseUnits('990', 6), // Min USDC expected
  destinationChainId: 137,
  hasSourceSwaps: true,
  hasDestinationCall: false
};

const tx = await polygonFacet.swapAndStartBridgeTokensViaPolygonBridge(
  bridgeData,
  swapData,
  { value: 0 }
);

await tx.wait();

​
Events

  • LiFiTransferStarted(BridgeData bridgeData) - Emitted when bridge transfer is initiated
  • LiFiTransferCompleted - Emitted when transfer completes
  • AssetSwapped - Emitted when using swapAndStart variant

​
Notes

  • This facet only supports bridging FROM Ethereum mainnet TO Polygon PoS
  • Bridging typically takes 7-8 minutes for checkpoint finality
  • The bridge uses the Plasma bridge by default for faster finality
  • For native ETH, the amount is sent as msg.value
  • For ERC20 tokens, approve the facet contract before calling
  • Token addresses on Polygon will be different from Ethereum (mapped tokens)

​
Bridge Times

  • Ethereum → Polygon: ~7-8 minutes (PoS bridge)
  • Polygon → Ethereum: ~3 hours (withdrawal requires checkpoint)

​
See Also

Build docs developers (and LLMs) love

Get started for freeTalk to us