> ## Documentation Index
> Fetch the complete documentation index at: https://sequence-0fb8d9e6-api_docs.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Checkout Modal

> The Checkout Modal provides developers with an easy way to implement cryptocurrency payments.

Sequence Checkout allows users to easily purchase an ERC721 or ERC1155 token with a primary or secondary sales contract such as a marketplace, with the following payment options:

* Purchase with any cryptocurrency in the wallet.
* Receive funds from another wallet to a Sequence wallet and purchase.
* Pay using a credit or debit card which will intelligently detect the correct provider for each region, chain and currency.
* Pay with another cryptocurrency in a wallet by doing an automated swap and purchase.

We have an integrated checkout flow that you can leverage by installing the dedicated library `@0xsequence/checkout` and using it in conjunction with `@0xsequence/connect`.

<Frame>
  <img src="https://mintcdn.com/sequence-0fb8d9e6-api_docs/lXs6FR-1Jpmoy0_f/images/kit/checkout-modal.png?fit=max&auto=format&n=lXs6FR-1Jpmoy0_f&q=85&s=29c58e213f2842dd1c886f92a760d439" alt="" width="427" height="812" data-path="images/kit/checkout-modal.png" />
</Frame>

<Note>
  In order to enable credit card payments for checkout, please get in touch with the Sequence team as your contract address will need to be allowlisted and go through a KYB process for your organization. Credit card payments only work on various networks mainnets
</Note>

# Installation and Setup

To integrate the checkout feature, follow these steps:

<Steps>
  <Step title="Install the `@0xsequence/checkout` library:">
    ```bash theme={null}
    npm install @0xsequence/checkout
    # or
    pnpm install @0xsequence/checkout
    # or
    yarn add @0xsequence/checkout
    ```
  </Step>

  <Step title="Place the `SequenceCheckoutProvider` below the SequenceConnect Provider in your App:">
    ```jsx theme={null}
    import { SequenceCheckoutProvider } from '@0xsequence/checkout'
    import { SequenceConnect } from '@0xsequence/connect'
    import { config } from './config'

    const App = () => {
      return (
        <SequenceConnect config={config}>
          <SequenceCheckoutProvider>
            <Page />
          </SequenceCheckoutProvider>
        </SequenceConnect>
      )
    }
    ```
  </Step>
</Steps>

Now we have the setup done, let's see how to use the checkout modal for different use cases.

## Custom Contract

We instantiate the `useSelectPaymentModal` hook to open the checkout modal and pass a settings object. In addition, for custom contracts, you can specify a contract ABI along with encoding the call data, in this case we are using `ethers` and `viem`'s `encodeFunctionData` utility.

```tsx theme={null}
import { useAccount } from 'wagmi'
import { useSelectPaymentModal, type SelectPaymentSettings } from '@0xsequence/checkout'
import { toHex } from 'viem'
import { encodeFunctionData } from 'viem'

const MyComponent = () => {
    const { address } = useAccount()
    const { openSelectPaymentModal } = useSelectPaymentModal()

    const onClick = () => {
        if (!address) {
            return
        }

        const currencyAddress = '0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359'
        const salesContractAddress = '0xe65b75eb7c58ffc0bf0e671d64d0e1c6cd0d3e5b'
        const collectionAddress = '0xdeb398f41ccd290ee5114df7e498cf04fac916cb'
        const price = '20000'

        const chainId = 137

        const erc1155SalesContractAbi = [
            {
                type: 'function',
                name: 'mint',
                inputs: [
                    { name: 'to', type: 'address', internalType: 'address' },
                    { name: 'tokenIds', type: 'uint256[]', internalType: 'uint256[]' },
                    { name: 'amounts', type: 'uint256[]', internalType: 'uint256[]' },
                    { name: 'data', type: 'bytes', internalType: 'bytes' },
                    { name: 'expectedPaymentToken', type: 'address', internalType: 'address' },
                    { name: 'maxTotal', type: 'uint256', internalType: 'uint256' },
                    { name: 'proof', type: 'bytes32[]', internalType: 'bytes32[]' }
                ],
                outputs: [],
                stateMutability: 'payable'
            }
        ]

        const collectibles = [
            {
                tokenId: '1',
                quantity: '1'
            }
        ]

        const purchaseTransactionData = encodeFunctionData({
            abi: erc1155SalesContractAbi,
            functionName: 'mint',
            args: [
                address,
                collectibles.map(c => BigInt(c.tokenId)),
                collectibles.map(c => BigInt(c.quantity)),
                toHex(0),
                currencyAddress,
                price,
                [toHex(0, { size: 32 })]
            ]
        })

        const selectPaymentModalSettings: SelectPaymentSettings = {
            collectibles: [
                {
                    tokenId: '1',
                    quantity: '1'
                }
            ],
            chain: chainId,
            price,
            targetContractAddress: salesContractAddress,
            recipientAddress: address,
            currencyAddress,
            collectionAddress,
            creditCardProviders: ['transak'],
            copyrightText: 'ⓒ2024 Sequence',
            onSuccess: (txnHash: string) => {
                console.log('success!', txnHash)
            },
            onError: (error: Error) => {
                console.error(error)
            },
            txData: purchaseTransactionData,
        }

        openSelectPaymentModal(selectPaymentModalSettings)
    }

    return <button onClick={onClick}>Buy ERC-1155 collectble!</button>
}
```

Congratulations! You’ve just learned how to use the Checkout Modal with Web SDK.