Ethereum Integration

This guide covers Ethereum integration with SwapKit, including wallet connections, token transfers, cross-chain swaps, and EVM-specific features.

Overview

Ethereum is the leading smart contract blockchain and the foundation of DeFi. SwapKit provides comprehensive Ethereum support through:

Ethereum Toolbox: Core blockchain operations (transfers, contract calls, gas estimation)
EVM Plugin: Enhanced features for decentralized exchanges and cross-chain operations
ERC-20 Support: Full support for Ethereum’s token standard
Multi-Wallet Support: Compatible with MetaMask, WalletConnect, Coinbase Wallet, and hardware wallets
Gas Optimization: EIP-1559 support with dynamic fee estimation

Getting Started

Installation

# Full SDK (recommended)
bun add @swapkit/sdk

# Individual packages for smaller bundles
bun add @swapkit/toolboxes @swapkit/plugins

// @noErrorValidation
import { createSwapKit, Chain } from '@swapkit/sdk';

const swapKit = createSwapKit();

const ethWallet = await swapKit.getWallet(Chain.Ethereum);

// @noErrorValidation
import { getEthereumToolbox } from '@swapkit/toolboxes/evm';


const ethToolbox = await getEthereumToolbox({
  phrase: "your twelve word mnemonic phrase here",

  derivationPath: [44, 60, 0, 0, 0]
});


const ethToolbox = await getEthereumToolbox({
  signer: customEthereumSigner,
  provider: customProvider
});

Ethereum Toolbox

Wallet Connection

Connect to Ethereum using various wallet types:

// @noErrorValidation
import { Chain, FeeOption } from "@swapkit/sdk";

await swapKit.connectKeystore([Chain.Ethereum], "your mnemonic phrase");

await swapKit.connectBrowserWallet(Chain.Ethereum);

await swapKit.connectWalletConnect([Chain.Ethereum]);

await swapKit.connectLedger([Chain.Ethereum]);

Native ETH Transfers

// @noErrorValidation
import { AssetValue } from "@swapkit/sdk";

const txHash = await swapKit.transfer({
  recipient: "0x742c4B4F3e0b5b069F5DCF8A65Eaf8d3E888a3E7",
  assetValue: AssetValue.from({
    chain: Chain.Ethereum,
    value: "0.1",
  }),
  feeOptionKey: FeeOption.Fast,
});

console.log(`Transaction hash: ${txHash}`);

ERC-20 Token Transfers

// @noErrorValidation

const usdcTransfer = await swapKit.transfer({
  recipient: "0x742c4B4F3e0b5b069F5DCF8A65Eaf8d3E888a3E7",
  assetValue: AssetValue.from({
    chain: Chain.Ethereum,
    symbol: "USDC",
    address: "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
    value: "100",
  }),
  feeOptionKey: FeeOption.Average,
});

const toolbox = await getEthereumToolbox({ phrase: "..." });

const balance = await toolbox.getBalance(
  "0x742c4B4F3e0b5b069F5DCF8A65Eaf8d3E888a3E7",
  "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48"
);

const tokenInfo = await toolbox.getTokenInfo(
  "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48"
);
console.log(tokenInfo);

Smart Contract Interactions

The Ethereum toolbox provides multiple ways to interact with smart contracts:

// @noErrorValidation

const result = await toolbox.call({
  contractAddress: "0x...",
  abi: contractABI,
  funcName: "balanceOf",
  funcParams: ["0x742c4B4F3e0b5b069F5DCF8A65Eaf8d3E888a3E7"],
});

const txHash = await toolbox.call({
  contractAddress: "0x...",
  abi: contractABI,
  funcName: "transfer",
  funcParams: ["0x742c4B4F3e0b5b069F5DCF8A65Eaf8d3E888a3E7", "1000000"],
  txOverrides: {
    gasLimit: "100000",
    value: "0",
  },
});

const gasEstimate = await toolbox.estimateCall({
  contractAddress: "0x...",
  abi: contractABI,
  funcName: "complexOperation",
  funcParams: [
    /* ... */
  ],
});

Token Approvals

ERC-20 tokens require approvals before they can be spent by contracts:

// @noErrorValidation

const isApproved = await toolbox.isApproved({
  contractAddress: "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
  spenderAddress: "0x...",
  amount: "1000000000",
});

if (!isApproved) {
  const approveTx = await toolbox.approve({
    contractAddress: "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
    spenderAddress: "0x...",
    amount: "1000000000",
  });

  console.log(`Approval transaction: ${approveTx}`);

  await toolbox.waitForTransaction(approveTx);
}

Gas Management

Ethereum supports both legacy and EIP-1559 fee structures:

// @noErrorValidation

const txParams = await toolbox.buildTransaction({
  recipient: "0x742c4B4F3e0b5b069F5DCF8A65Eaf8d3E888a3E7",
  amount: AssetValue.from({ chain: Chain.Ethereum, value: "0.1" }),
  feeOptionKey: FeeOption.Fast,

  maxFeePerGas: "20000000000",
  maxPriorityFeePerGas: "2000000000",
});

const legacyTx = await toolbox.buildTransaction({
  recipient: "0x742c4B4F3e0b5b069F5DCF8A65Eaf8d3E888a3E7",
  amount: AssetValue.from({ chain: Chain.Ethereum, value: "0.1" }),
  feeOptionKey: FeeOption.Fast,
  gasPrice: "20000000000",
});

const gasInfo = await toolbox.getGasPrices();
console.log({
  slow: gasInfo.average,
  standard: gasInfo.fast,
  fast: gasInfo.fastest,
});

Cross-Chain Swaps

Use Ethereum as source or destination for cross-chain swaps via THORChain:

// @noErrorValidation

const ethToBtcQuote = await swapKit.getQuote({
  sellAsset: "ETH.ETH",
  sellAmount: "1",
  buyAsset: "BTC.BTC",
  senderAddress: swapKit.getAddress(Chain.Ethereum),
  recipientAddress: swapKit.getAddress(Chain.Bitcoin),
});

const swapTx = await swapKit.swap({
  route: ethToBtcQuote.routes[0],
  feeOptionKey: FeeOption.Fast,
});

const usdcToRuneQuote = await swapKit.getQuote({
  sellAsset: "ETH.USDC-0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
  sellAmount: "1000",
  buyAsset: "THOR.RUNE",
  senderAddress: swapKit.getAddress(Chain.Ethereum),
  recipientAddress: swapKit.getAddress(Chain.THORChain),
});

const swapResult = await swapKit.swap({
  route: usdcToRuneQuote.routes[0],
  feeOptionKey: FeeOption.Average,
});

DEX Integration

SwapKit supports major Ethereum DEXs through integrated routing:

// @noErrorValidation

const uniswapQuote = await swapKit.getQuote({
  sellAsset: "ETH.ETH",
  sellAmount: "1",
  buyAsset: "ETH.USDC-0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
  senderAddress: swapKit.getAddress(Chain.Ethereum),
  recipientAddress: swapKit.getAddress(Chain.Ethereum),
  providers: ["UNISWAPV3"],
});

const oneinchQuote = await swapKit.getQuote({
  sellAsset: "ETH.DAI-0x6B175474E89094C44Da98b954EedeAC495271d0F",
  sellAmount: "1000",
  buyAsset: "ETH.WBTC-0x2260FAC5E5542a773Aa44fBCfeDf7C193bc2C599",
  senderAddress: swapKit.getAddress(Chain.Ethereum),
  recipientAddress: swapKit.getAddress(Chain.Ethereum),
  providers: ["ONEINCH"],
});

const dexSwap = await swapKit.swap({
  route: oneinchQuote.routes[0],
  feeOptionKey: FeeOption.Fast,
});

Address Validation

// @noErrorValidation
import { validateEthereumAddress } from "@swapkit/toolboxes/evm";

const isValidAddress = validateEthereumAddress(
  "0x742c4B4F3e0b5b069F5DCF8A65Eaf8d3E888a3E7"
);
console.log(isValidAddress);

import { getAddress } from "ethers";

try {
  const checksumAddress = getAddress(
    "0x742c4b4f3e0b5b069f5dcf8a65eaf8d3e888a3e7"
  );
  console.log(checksumAddress);
} catch (error) {
  console.error("Invalid address");
}

Fee Rate Configuration

Configure gas fees based on network conditions:

// @noErrorValidation
import { FeeOption } from "@swapkit/sdk";

const feeOptions = {
  [FeeOption.Average]: 1.0,
  [FeeOption.Fast]: 1.5,
  [FeeOption.Fastest]: 2.0,
};

const customTx = await swapKit.transfer({
  recipient: "0x742c4B4F3e0b5b069F5DCF8A65Eaf8d3E888a3E7",
  assetValue: AssetValue.from({ chain: Chain.Ethereum, value: "0.1" }),
  gasLimit: "21000",
  maxFeePerGas: "30000000000",
  maxPriorityFeePerGas: "2000000000",
});

Error Handling

Handle Ethereum-specific errors appropriately:

// @noErrorValidation
import { SwapKitError } from "@swapkit/sdk";

try {
  await swapKit.transfer({
    /* ... */
  });
} catch (error) {
  if (error instanceof SwapKitError) {
    switch (error.code) {
      case "toolbox_evm_insufficient_funds":
        console.error("Insufficient ETH for transaction");
        break;
      case "toolbox_evm_gas_estimation_failed":
        console.error("Could not estimate gas");
        break;
      case "toolbox_evm_transaction_failed":
        console.error("Transaction failed:", error.cause);
        break;
      case "toolbox_evm_invalid_address":
        console.error("Invalid Ethereum address");
        break;
      case "toolbox_evm_token_not_approved":
        console.error("Token approval required");
        break;
      default:
        console.error("Unknown error:", error);
    }
  }
}

Advanced Features

Custom Provider Configuration

// @noErrorValidation
import { JsonRpcProvider } from 'ethers';


const customProvider = new JsonRpcProvider("https:

const toolbox = await getEthereumToolbox({
  phrase: "your mnemonic",
  provider: customProvider
});


import { SKConfig } from '@swapkit/sdk';

SKConfig.setRpcUrl(Chain.Ethereum, [
  "https:
  "https:
  "https:
]);

Working with Test Networks

// @noErrorValidation

SKConfig.setRpcUrl(Chain.Ethereum, "https:
SKConfig.setEnv('isMainnet', false);


const testToolbox = await getEthereumToolbox({ phrase: "..." });

Transaction Monitoring

// @noErrorValidation

const txHash = await swapKit.transfer({
  /* ... */
});

const receipt = await toolbox.waitForTransaction(txHash);
console.log(`Confirmed in block ${receipt.blockNumber}`);

const status = await toolbox.getTransactionStatus(txHash);
console.log(status);

const txDetails = await toolbox.getTransaction(txHash);
console.log({
  blockNumber: txDetails.blockNumber,
  gasUsed: txDetails.gasUsed,
  status: txDetails.status,
});

Best Practices

Always validate addresses before sending transactions:

import { isAddress } from "ethers";

if (!isAddress(recipient)) {
  throw new Error("Invalid Ethereum address");
}

Check balances before transactions:

const balance = await toolbox.getBalance(senderAddress);
const requiredAmount = AssetValue.from({
  chain: Chain.Ethereum,
  value: "0.1",
});

if (balance.lt(requiredAmount.add(estimatedGas))) {
  throw new Error("Insufficient balance");
}

Use appropriate gas limits for different operations:

const gasLimits = {
  ethTransfer: "21000",
  erc20Transfer: "65000",
  contractCall: "100000-500000",
  complexDeFi: "500000+",
};

Handle network congestion:

const gasInfo = await toolbox.getGasPrices();

if (gasInfo.fast > 50000000000) {
  console.warn("Network is congested, consider waiting");
}

Batch operations when possible:

const multicallResults = await toolbox.multicall([
  { target: "0x...", callData: "0x..." },
  { target: "0x...", callData: "0x..." },
]);

Chain-Specific Features

ENS (Ethereum Name Service)

// @noErrorValidation

const address = await toolbox.resolveName("vitalik.eth");
console.log(address);

const ensName = await toolbox.lookupAddress(
  "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"
);
console.log(ensName);

MEV Protection

// @noErrorValidation

const protectedProvider = new JsonRpcProvider("https:


const privateTx = await toolbox.sendPrivateTransaction({
  /* transaction parameters */
});

Troubleshooting

Common Issues

“Insufficient funds for gas”
- Ensure you have enough ETH to cover transaction gas costs
- Check gas price isn’t set too high
“Transaction underpriced”
- Increase gas price or use EIP-1559 with higher maxFeePerGas
- Use FeeOption.Fast or FeeOption.Fastest
“Nonce too low”
- Transaction nonce conflicts with pending transaction
- Wait for previous transactions to confirm
Token transfer fails
- Check token approval status
- Verify token contract address is correct
- Ensure recipient address can receive tokens

Debug Mode

// @noErrorValidation

import { SKConfig } from "@swapkit/sdk";

SKConfig.setEnv("debug", true);

const txParams = await toolbox.buildTransaction({
  recipient: "0x...",
  amount: AssetValue.from({ chain: Chain.Ethereum, value: "0.1" }),
});

console.log("Transaction parameters:", txParams);

API Reference Summary

Core Methods

getBalance() - Get ETH or token balance
transfer() - Send ETH or tokens
buildTransaction() - Construct transaction parameters
call() - Execute smart contract functions
estimateCall() - Estimate gas for contract calls

Token Methods

approve() - Approve token spending
isApproved() - Check approval status
getTokenInfo() - Get token metadata

Utility Methods

getGasPrices() - Get current gas prices
waitForTransaction() - Wait for confirmation
getTransaction() - Get transaction details
validateAddress() - Validate address format

🌐 Other EVM Chains

Leverage the same patterns on other EVM-compatible networks. - Arbitrum - Layer 2 scaling with lower fees - Polygon - Faster transactions and DeFi ecosystem - Avalanche - High-throughput smart contracts - BNB Smart Chain - BSC DeFi ecosystem

🔄 Cross-Chain Operations

Use Ethereum in cross-chain swaps and DeFi strategies. - Cross-Chain Swaps - ETH ↔ BTC, ETH ↔ THOR - THORChain Features - Native liquidity access - Advanced Features - Synthetic assets and more

💳 Wallet Integration

Connect Ethereum wallets across different types and providers. - MetaMask - Most popular browser wallet - WalletConnect - Mobile wallet connections - Hardware Wallets - Secure hardware signing

📋 Production Deployment

Optimize your Ethereum integration for production use. - Production Best Practices - Deployment guidelines - Security Guidelines - Protect user funds and data - Performance Tips - Optimize gas and speed

New to SwapKit? Start with Getting Started to learn the basics.

Building multi-chain apps? Explore Bitcoin and Cosmos integrations.

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