3️⃣3️⃣ Request Route & Execute Swap

Before making a swap, you need to request the best route from the SwapKit API.

To request possible routes, follow the instructions below.

Step 1: Build a QuoteParams object

The QuoteParams object describes a swap to/from any of the supported blockchains and contains all information necessary to determine the best routes. It is defined by the following interface:

interface QuoteParams {
    affiliateBasisPoints?: string;
    buyAsset: string;
    recipientAddress?: string;
    sellAmount: string;
    sellAsset: string;
    senderAddress?: string;
    slippage: string;
}

The buyAsset & sellAsset must be of the format 'chain.ticker' For example, BTC.BTC.

The recipientAddress must be a valid address for the buyAsset blockchain. Similarly the senderAddress must be a valid address for the sellAsset.

Step 2. Call getQuote from SwapKitApi package

After creating the quoteParams object, you can pass it to the getQuote function of the SwapKitApi class.

// or directly from @swapkit/api
import { SwapKitApi } from '@swapkit/sdk'

const quoteParams = {
    sellAsset: 'BTC.BTC',
    sellAmount: '1',
    buyAsset: 'ETH.ETH',
    senderAddress: '...', // A valid Ethereum address
    recipientAddress: '...', // A valid Bitcoin address
    slippage: '3',
};

const { routes } = await SwapKitApi.getQuote(quoteParams);

Step 3: Choose fee option multiplier, route & execute swap

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

const bestRoute = routes.find(({ optimal }) => optimal)

const txHash = await skClient.swap({
    route: bestRoute,
    recipient: '...',
    feeOptionKey: FeeOption.Fast
    // FeeOption multiplies current base fee by:
    // Average => 1.2 
    // Fast => 1.5
    // Fastest => 2
});

// Returns explorer url like etherscan, viewblock, etc.
const explorerUrl = skClient.getExplorerTxUrl(inputChain, txHash)

The skClient used above assumes a wallet has been connected as described in Set up the SDK.

Executing ERC20 Swaps with tokens on EVM chains need approval spending. Check if asset has been approved with built in methods.

import { AmountWithBaseDenom, AssetEntity } from '@swapkit/sdk'

const isApproved = skClient.isAssetApprovedForContract(
  asset, // AssetEntity
  contractAddress: selectedRoute.contract
  amount, // AmountWithBaseDenom => amount to check that's possible to spent, default MaxInt256
)

const approveTx = skClient.approveAssetForContract(
  asset, // AssetEntity
  contractAddress: selectedRoute.contract
  amount, // AmountWithBaseDenom => amount approved to spent, default MaxInt256
)