Defi Your App

When businesses and individuals make financial transactions, it often includes swapping assets and then storing eligible assets in a yield generating strategy. This guide will show you how to quickly add these features to your app with pre-built React components from OnchainKit.

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Ready-to-use components

• <Swap />: Swap assets directly within your app.
• <Earn />: Generate yield directly within your app.
• <FundCard />: Fund their wallets with fiat (via USDC, Apple Pay, or debit card) without leaving your app.
• <Buy />: Purchase tokens directly within your app.

By embedding the Swap and Earn components, your users don’t need to leave your app to execute these common actions. For users who lack onchain funds, the Fund and Buy components offer an integrated fiat-to-crypto onramp.

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Swap Component Integration

The Swap component lets users exchange one token for another directly in your application. It fetches live quotes, builds transactions, and executes swaps—abstracting the underlying complexity.

Lets add the Swap component to your app.

npm create onchain@latest

 import { SwapDefault } from '@coinbase/onchainkit/swap'; 
 import type { Token } from '@coinbase/onchainkit/token';

 const eth: Token = {
 name: 'ETH',
 address: '',
 symbol: 'ETH',
 decimals: 18,
 image:
     'https://wallet-api-production.s3.amazonaws.com/uploads/tokens/eth_288.png',
 chainId: 8453,
 };

 const usdc: Token = {
 name: 'USDC',
 address: '0x833589fcd6edb6e08f4c7c32d4f71b54bda02913',
 symbol: 'USDC',
 decimals: 6,
 image:
     'https://d3r81g40ycuhqg.cloudfront.net/wallet/wais/44/2b/442b80bd16af0c0d9b22e03a16753823fe826e5bfd457292b55fa0ba8c1ba213-ZWUzYjJmZGUtMDYxNy00NDcyLTg0NjQtMWI4OGEwYjBiODE2',
 chainId: 8453,
 };

 <SwapDefault
 from={[eth]} 
 to={[usdc]} 
 /> 

You should now see the following swap component in your app:

The Swap component uses Uniswap V3 as the default router, but you can also use the 0x Aggregator by setting the experimental.useAggregator prop to true.

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Swap Settings

The Swap component comes preconfigured but is highly customizable. Just a couple of the settings you can customize:

• Swap settings
• bidirectional or unidirectional swaps
• Gasless swaps with paymasters

To learn more about how to customize the Swap component, check out the Swap docs.

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Earn Component Integration

The Earn component enables users to deposit assets into yield-generating vaults and withdraw them later—all within your app. The Earn component currently supports Morpho vaults on Base.

// @noErrors: 2307
import { Earn } from '@coinbase/onchainkit/earn'; 

<Earn vaultAddress="0x7BfA7C4f149E7415b73bdeDfe609237e29CBF34A" />

Just like that, you’ve added a yield-generating vault to your app.

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Advanced Customizations

Similar to the Swap component, the Earn component is highly customizable. Lets customize our component to include custom deposit buttons for a streamlined user experience.

• useEarnContext to access the component’s context values, EarnDeposit and EarnDetails
• DepositButton to render custom deposit buttons

// @noErrors: 2307
import { Earn, useEarnContext } from '@coinbase/onchainkit/earn';
import { CustomDepositButtons } from '@/custom-deposit-buttons';

  <Earn vaultAddress="0x7BfA7C4f149E7415b73bdeDfe609237e29CBF34A">
      <CustomDepositButtons />
  </Earn>

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Onboarding Users in DeFi

In order to leverage the <FundCard/> and <Buy /> components, users need to have funds in their wallet. If user’s don’t have funds, they’ll need to onramp fiat or buy tokens in order to transact. We’ll explore two out-of-the-box solutions from OnchainKit below.

The Fund component (via <FundCard />) offers a complete fiat onramp experience, allowing users to add funds to their wallet directly in your app. It provides:

• Amount input with fiat/crypto switching
• Payment method selection (Coinbase, Apple Pay, Debit Card)
• Automatic exchange rate updates
• Smart handling of payment method restrictions (based on country and subdivision)

import { FundCard } from '@coinbase/onchainkit/fund';

<FundCard
  assetSymbol="ETH"
  country="US"
  currency="USD"
/>;

To learn more about the FundCard component and its features, check out the FundCard docs.

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The Buy Component

The Buy components provide a comprehensive interface for users to purchase Tokens.

The Buy component supports token swaps from USDC and ETH by default with the option to provide an additional token of choice using the fromToken prop. Users are able to purchase tokens using their Coinbase account, Apple Pay, or debit card.

import { Buy } from '@coinbase/onchainkit/buy'; 
import type { Token } from '@coinbase/onchainkit/token';

export default function BuyComponents() { 
  const degenToken: Token = {
    name: 'DEGEN',
    address: '0x4ed4e862860bed51a9570b96d89af5e1b0efefed',
    symbol: 'DEGEN',
    decimals: 18,
    image:
    'https://d3r81g40ycuhqg.cloudfront.net/wallet/wais/3b/bf/3bbf118b5e6dc2f9e7fc607a6e7526647b4ba8f0bea87125f971446d57b296d2-MDNmNjY0MmEtNGFiZi00N2I0LWIwMTItMDUyMzg2ZDZhMWNm',
    chainId: 8453,
  };

  return ( 
    <Buy toToken={degenToken} />
  ) 
}

By combining Swap, Earn, Fund, and Buy with these additional tools, you can quickly build a robust in-app DeFi experience with minimal development overhead. This lets you focus on building your unique value proposition.

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Next Steps

If you’re using these components, its likely you’ll benefit from the following components:

• <Transaction/>: Provides a high-level transaction interface for executing custom onchain transactions.

• <TokenChip/>: Offers utilities for token selection and display, ideal for building wallet-like interfaces.

• <WalletIsland/>: An advanced, draggable wallet widget that consolidates wallet management (QR code, buy options, swap, portfolio view) in one interface.

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Go Gasless

For the <Buy /> and <Swap/> components, you can enable gasless transactions by setting the isSponsored prop to true.