Credit Purchase Integration: USDC Settled Directly to BYO Wallet (EVM)

This page is for advanced / cryptocurrency-native companies. If that’s not you, head back to the Quickstart for the standard flows.

Summary

This implementation guide outlines how Merchants on EVM chains can accept pay-ins and settle to a Merchant’s EVM wallet.

Setup

Complete account setup first

This integration assumes you’ve completed the Account Setup prerequisites — sandbox merchant account, API key, team access, and any product-specific configuration (settlement location, chargeback protection, or wallet funding).

Developer Resources

Quick Links:

Authorization Headers:

Authorization — Your API key from the merchant dashboard.
x-coinflow-auth-user-id — A unique customer ID from your own systems identifying the payer or payee.
x-coinflow-auth-session-key — A JWT that authorizes the payer. Valid for 24 hours; refresh after expiry.

Checkout Implementation

React SDK

Share payer events with Coinflow Sharing major events that a payer makes throughout their lifecycle on your website prior to them making a purchase will allow us to collect more information about them and improve your approval rates.

SignUpEvent

1 curl --request POST \
2      --url https://api-sandbox.coinflow.cash/api/events \
3      --header 'Authorization: <YOUR_API_KEY>' \
4      --header 'content-type: application/json' \
5      --data '
6 {
7   "eventType": "SignUp",
8   "customerId": "user-123-abc",
9   "country": "US",
10   "username": "therock72",
11   "email": "dwaynejohnson@gmail.com",
12   "firstName": "Dwayne",
13   "lastName": "Johnson"
14 }
15 '

SignInEvent

1 curl --request POST \
2      --url https://api-sandbox.coinflow.cash/api/events \
3      --header 'Authorization: <YOUR_API_KEY>' \
4      --header 'content-type: application/json' \
5      --data '
6 {
7   "eventType": "SignIn",
8   "customerId": "user-123-abc",
9   "country": "US",
10   "email": "dwaynejohnson@gmail.com"
11 }
12 '

SignInFailureEvent

1 curl --request POST \
2      --url https://api-sandbox.coinflow.cash/api/events \
3      --header 'Authorization: <YOUR_API_KEY>' \
4      --header 'content-type: application/json' \
5      --data '
6 {
7   "eventType": "SignInFailure",
8   "customerId": "user-123-abc",
9   "country": "US",
10   "email": "dwaynejohnson@gmail.com",
11   "failureReason": "Password Failed"
12 }
13 '

BuyerChallengeEvent

1 curl --request POST \
2      --url https://api-sandbox.coinflow.cash/api/events \
3      --header 'Authorization: <YOUR_API_KEY>' \
4      --header 'content-type: application/json' \
5      --data '
6 {
7   "eventType": "BuyerChallenge",
8   "type": "thirdPartyKyc",
9   "status": "successfullyFulfilled",
10   "customerId": "user-123-abc",
11   "country": "US",
12   "email": "dwaynejohnson@gmail.com"
13 }
14 '

For full descriptions and timing guidance for each event, see Sending Payer Events.

Install Coinflow package

npm i @coinflowlabs/react

Tokenize the checkout parameters. This encrypts the checkout parameters so bad actors cannot tamper with the checkout args.

Request

1 curl --location 'https://api-sandbox.coinflow.cash/api/checkout/jwt-token' \
2 --header 'Authorization: YOUR_API_KEY' \
3 --header 'accept: application/json' \
4 --header 'content-type: application/json' \
5 --data-raw '
6 {
7   "webhookInfo": {
8     "example": "{\"nftId\":\"123abc\"}"
9   },
10   "subtotal": {
11     "currency": "USD",
12     "cents": 100
13   },
14   "transactionData": {
15     "destination": "0x...", // Whitelisted merchant wallet address
16     "type": "token"
17   },
18   "email": "payer@gmail.com",
19   "blockchain": "base",
20   "chargebackProtectionData": [
21     {
22       "productName": "My Product",
23       "quantity": 1,
24       "rawProductData": {
25         "example": "{\"description\":\"description of nft\"}"
26       },
27       "productType": "inGameProduct" // This will change on prod
28     }
29   ],
30   "deviceId": "123456789"
31 	"settlementType": "Credits"
32 }
33 '

Response

 {
     "checkoutJwtToken": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJkYXRhIjoi456C4oKW26LXguCjgOKYgueAleiAnN2j5IGM4LGn46CD5oOb4LCF44CQ7Iqy4YCF6KSz4KCI7KaczLDGkOuhgNqE44iA7rWwybDgp6DHgOCumeawgOSQqeSio0LgsJ3njaPmoYXItOa1ku6AjOyFieKmlOiTke67iOWCguWxiOmroOSNuO65suOou-mUremsreWZqOSytueBrOeBpOGgqOSZiOaxrOKhiOiRpOmitOGxiOG7vuuYnOeDmOeBjOChhuCglOuTiOunuOyYlOawmOqXtuujvuSyuuuSnOy7mOqglOSZqOahpOeVrOiwmOShsOKglOaphuGhjOuXjeiRhuaStOSZjFx1ZGQxY-K7k-uQlFx1ZDg2NO-kqOmUq-qHg-6Xqu-pmuySoeGxhuSVhueDquqYiOmHlOShmuGzmOKgnOaikeSuuFx1ZGExOOebvuKisuuguOiSqdOD4LCy4Y6B7IqZ5LO045Cb6qeM4o2D6Iyc7KOR4ZKt4ZyC6I2h6oCy44SMzZPSheyHmeixmOOyhsyE5IWC7oCo5LCO46uJ0rfvg6Dos6jMmOWqguiMi-qSjOu4nOqdkuivsuerpeWljOGmlemCi-6ZmeyFsOuItOCouuKDpeqCoeuAnOiImeGciuyNqeaIiuSxseWkrtek64S4XHVkODRi4YiN6LqnwqDngLjojJrhnIzsrYLpm43rqI3jjKbotoztmJjigYLlkoTihILoloXpi5HtkafijJHolZTogYLosoHnlZvmmonohYDnhbHooLTrjIXcr-mWou2GsOSwsuGchOm6g-qrmOGBmeieoOyfoemhiOWBsOGSqeWohOyzkO6rm-yhmeOQrOaAq-STqeGnpuSxteCoquWSgO6JkuqwnuGBmtys6Yax4rGQ5JS46rSH6ICF74iAIiwibWVyY2hhbnRJZCI6InRlc3R0ZXN0IiwiaWRlbXBvdGVuY3lLZXkiOiJJSzVlZWE3YzI3LWEyMjgtNDcyMC1iYTVkLWI1ZDA0ZDUzMzA3MCIsInN1YnRvdGFsIjp7ImN1cnJlbmN5IjoiVVNEIiwiY2VudHMiOjUwMH0sImlhdCI6MTc0Mjg1NTY3OCwiZXhwIjoxNzQyOTQyMDc4fQ.2dGfWnazfyHaz_uEWKM9RU-jh-tXUSMPFZJdNvmMPwo"
   }

Implement CoinflowPurchase component

1 <CoinflowPurchase
2   wallet={{
3     address: string;
4     sendTransaction: (transaction) => Promise<{hash: string}>; // This isn't technically needed as the end user's wallet is never sending a transaction
5     signMessage: (message: string) => Promise;
6   }}
7   merchantId={'YOUR_MERCHANT_ID'} // Replace with your merchant ID
8   env={'sandbox || prod'}
9   onSuccess={(...args) => console.log('Purchase Success', args)}
10   blockchain={'base'}
11   subtotal={{cents: 100, currency: Currency.USD}} // Purchase amount in usdc
12 jwtToken = {'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJkYXRhIjoi456C4oKW26LXguCjgOKYgueAleiAnN2j5IGM4LGn46CD5oOb4LCF44CQ7Iqy4YCF6KSz4KCI7KaczLDGkOuhgNqE44iA7rWwybDgp6DHgOCumeawgOSQqeSio0LgsJ3njaPmoYXItOa1ku6AjOyFieKmlOiTke67iOWCguWxiOmroOSNuO65suOou-mUremsreWZqOSytueBrOeBpOGgqOSZiOaxrOKhiOiRpOmitOGxiOG7vuuYnOeDmOeBjOChhuCglOuTiOunuOyYlOawmOqXtuujvuSyuuuSnOy7mOqglOSZqOahpOeVrOiwmOShsOKglOaphuGhjOuXjeiRhuaStOSZjFx1ZGQxY-K7k-uQlFx1ZDg2NO-kqOmUq-qHg-6Xqu-pmuySoeGxhuSVhueDquqYiOmHlOShmuGzmOKgnOaikeSuuFx1ZGExOOebvuKisuuguOiSqdOD4LCy4Y6B7IqZ5LO045Cb6qeM4o2D6Iyc7KOR4ZKt4ZyC6I2h6oCy44SMzZPSheyHmeixmOOyhsyE5IWC7oCo5LCO46uJ0rfvg6Dos6jMmOWqguiMi-qSjOu4nOqdkuivsuerpeWljOGmlemCi-6ZmeyFsOuItOCouuKDpeqCoeuAnOiImeGciuyNqeaIiuSxseWkrtek64S4XHVkODRi4YiN6LqnwqDngLjojJrhnIzsrYLpm43rqI3jjKbotoztmJjigYLlkoTihILoloXpi5HtkafijJHolZTogYLosoHnlZvmmonohYDnhbHooLTrjIXcr-mWou2GsOSwsuGchOm6g-qrmOGBmeieoOyfoemhiOWBsOGSqeWohOyzkO6rm-yhmeOQrOaAq-STqeGnpuSxteCoquWSgO6JkuqwnuGBmtys6Yax4rGQ5JS46rSH6ICF74iAIiwibWVyY2hhbnRJZCI6InRlc3R0ZXN0IiwiaWRlbXBvdGVuY3lLZXkiOiJJSzVlZWE3YzI3LWEyMjgtNDcyMC1iYTVkLWI1ZDA0ZDUzMzA3MCIsInN1YnRvdGFsIjp7ImN1cnJlbmN5IjoiVVNEIiwiY2VudHMiOjUwMH0sImlhdCI6MTc0Mjg1NTY3OCwiZXhwIjoxNzQyOTQyMDc4fQ.2dGfWnazfyHaz_uEWKM9RU-jh-tXUSMPFZJdNvmMPwo'}
13 />

Customize the UI on your dashboard
Whitelist your url By whitelisting your domain, checkout can only be completed on your domain. This protects against bad actors trying to take your checkout link and injecting it onto their site.

API Implementation

SignUpEvent

1 curl --request POST \
2      --url https://api-sandbox.coinflow.cash/api/events \
3      --header 'Authorization: <YOUR_API_KEY>' \
4      --header 'content-type: application/json' \
5      --data '
6 {
7   "eventType": "SignUp",
8   "customerId": "user-123-abc",
9   "country": "US",
10   "username": "therock72",
11   "email": "dwaynejohnson@gmail.com",
12   "firstName": "Dwayne",
13   "lastName": "Johnson"
14 }
15 '

SignInEvent

1 curl --request POST \
2      --url https://api-sandbox.coinflow.cash/api/events \
3      --header 'Authorization: <YOUR_API_KEY>' \
4      --header 'content-type: application/json' \
5      --data '
6 {
7   "eventType": "SignIn",
8   "customerId": "user-123-abc",
9   "country": "US",
10   "email": "dwaynejohnson@gmail.com"
11 }
12 '

SignInFailureEvent

1 curl --request POST \
2      --url https://api-sandbox.coinflow.cash/api/events \
3      --header 'Authorization: <YOUR_API_KEY>' \
4      --header 'content-type: application/json' \
5      --data '
6 {
7   "eventType": "SignInFailure",
8   "customerId": "user-123-abc",
9   "country": "US",
10   "email": "dwaynejohnson@gmail.com",
11   "failureReason": "Password Failed"
12 }
13 '

BuyerChallengeEvent

1 curl --request POST \
2      --url https://api-sandbox.coinflow.cash/api/events \
3      --header 'Authorization: <YOUR_API_KEY>' \
4      --header 'content-type: application/json' \
5      --data '
6 {
7   "eventType": "BuyerChallenge",
8   "type": "thirdPartyKyc",
9   "status": "successfullyFulfilled",
10   "customerId": "user-123-abc",
11   "country": "US",
12   "email": "dwaynejohnson@gmail.com"
13 }
14 '

For full descriptions and timing guidance for each event, see Sending Payer Events.

Fetch a session key This creates a JWT token for the customer, and authorizes the user to call these endpoints. You will pass the returned session key as x-coinflow-auth-session-key header.

Request

1 curl --request GET \
2      --url https://api-sandbox.coinflow.cash/api/auth/session-key \
3      --header 'Authorization: YOUR_API_KEY' \
4      --header 'accept: application/json' \
5      --header 'x-coinflow-auth-user-id: customer123'

Response

{
  "key": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJjdXN0b21lcklkIjoiY3VzdG9tZXIxMjMiLCJtZXJjaGFudElkIjoidHlsZWUiLCJpYXQiOjE3MzQzNjY4NDksImV4cCI6MTczNDQ1MzI0OX0.rxyzFgSZNtIR7KguHyb7MFq2xeDNKH2-3NA49eHH-7Y"
}

Get the Totals for the checkout to show the customer a quote inclusive of all fees.

Request

1 curl --request POST \
2      --url https://api-sandbox.coinflow.cash/api/checkout/totals/merchantId \
3      --header 'accept: application/json' \
4      --header 'content-type: application/json' \
5      --header 'x-coinflow-auth-session-key: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJjdXN0b21lcklkIjoiY3VzdG9tZXIxMjMiLCJtZXJjaGFudElkIjoidHlsZWUiLCJpYXQiOjE3MzQzNjY4NDksImV4cCI6MTczNDQ1MzI0OX0.rxyzFgSZNtIR7KguHyb7MFq2xeDNKH2-3NA49eHH-7Y' \
6      --data '
7 {
8   "subtotal": {
9     "cents": 100
10   },
11   "settlementType": "USDC"
12 }
13 '

Response

{
  "card": {
    "subtotal": {
      "cents": 100
    },
    "creditCardFees": {
      "cents": 40
    },
    "chargebackProtectionFees": {
      "cents": 0
    },
    "gasFees": {
      "cents": 0
    },
    "total": {
      "cents": 140
    }
  },
  "ach": {
    "subtotal": {
      "cents": 100
    },
    "creditCardFees": {
      "cents": 100
    },
    "chargebackProtectionFees": {
      "cents": 0
    },
    "gasFees": {
      "cents": 0
    },
    "total": {
      "cents": 200
    }
  }
}

Tokenize the Credit Card Number. See tab: Tokenize New Card

Tokenize the checkout parameters. This encrypts the checkout parameters so bad actors cannot tamper with the checkout args.

Request

1 curl --request POST \
2      --url https://api-sandbox.coinflow.cash/api/checkout/jwt-token \
3      --header 'Authorization: YOUR_API_KEY' \
4      --header 'accept: application/json' \
5      --header 'content-type: application/json' \
6      --data '
7 {
8   "subtotal": {
9     "currency": "USD",
10     "cents": 500
11   },
12   "blockchain": "base",
13   "settlementType": "Credits"
14 }
15 '

Response

{
  "checkoutJwtToken": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJkYXRhIjoi456C4oKW26LXguC7gOSMgueAheiEieWIgOyCg-GglO2cgOSwg-aFiOiEmOSgiOyBljjJo-iBpuKyluSsgOyxiVx1MDAxYeGDuMea7oCE7oCT7ICD6ICX57GEwojimpDomIjis7nhrafqiYHjq7zls6Dll4HkrpflqYnvgpDuvp_IouuToeqer-aTjeGbtOuloOqLgeK0lu2RkeGiuO6xkOuDoOmEve6nqOKgqeqkme6lsOWBqO-BkeqjoOijkuKzoOykmOWlqeeGqOunseqjouKgnOWng-GiieK3suWAqeGhiu2KiOGKkeOUmOKhke-JteeAsOmBouSnmO6SuOKxkOmiieykmeeGsuiiq-qgke-HquWkmOSAgeeygCIsIm1lcmNoYW50SWQiOiJtZWxsbyIsImlkZW1wb3RlbmN5S2V5IjoiSUtiYmRkMWI1NS1iZWE3LTRkMzMtOWRkMi0wNGZhZDEwNzFiZDciLCJzdWJ0b3RhbCI6eyJjdXJyZW5jeSI6IlVTRCIsImNlbnRzIjo1MDB9LCJpYXQiOjE3NTI2MTgwOTEsImV4cCI6MTc1MjYxOTg5MX0.tBsJpIMVe0tyeLcu5xfWDKtodFoi44bQKqAckVXq5DI"
}

Enable a New Card Checkout This endpoint will enable a new user who has never made a purchase to complete their purchase with a credit card. Below is an example of how you’d call the card checkout endpoint:

Request

1 curl --location 'https://api-sandbox.coinflow.cash/api/checkout/card/mello' \
2 --header 'accept: application/json' \
3 --header 'content-type: application/json' \
4 --header 'user-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.0.0 Safari/537.36' \
5 --header 'x-coinflow-auth-session-key: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ3YWxsZXQiOiIweGQxMWNjMUQwMzdCNDkwOTgxMzBCRGVCNTkyZDQ2OEUzZmUxMzEyNDAiLCJibG9ja2NoYWluIjoicG9seWdvbiIsIm1lcmNoYW50SWQiOiJtZWxsbyIsImlhdCI6MTc1MjYxODE5MSwiZXhwIjoxNzUyNzA0NTkxfQ.TVQX91Pq-xTimiSxZ6_HZP_G-TVrTmtf93cqZY34nuU' \
6 --header 'x-coinflow-client-ip: 64.227.3.71' \
7 --header 'x-device-id: 123456789' \
8 --data-raw '
9 {
10   "subtotal": {
11     "currency": "USD",
12     "cents": 500
13   },
14   "card": {
15     "cardToken": "230377JSUM3F0275",
16     "expYear": "30",
17     "expMonth": "10",
18     "email": "iamapayer@gmail.com",
19     "firstName": "Dwayne",
20     "lastName": "Johnson",
21     "address1": "380 Prospect Ave",
22     "city": "Brooklyn",
23     "zip": "11215",
24     "state": "NY",
25     "country": "US"
26   },
27   "jwtToken": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJkYXRhIjoi456C4oKW26LXguC7gOSMgueAheiEieWIgOyCg-GglO2cgOSwg-aFiOiEmOSgiOyBljjJo-iBpuKyluSsgOyxiVx1MDAxYeGDuMea7oCE7oCT7ICD6ICX57GEwojimpDomIjis7nhrafqiYHjq7zls6Dll4HkrpflqYnvgpDuvp_IouuToeqer-aTjeGbtOuloOqLgeK0lu2RkeGiuO6xkOuDoOmEve6nqOKgqeqkme6lsOWBqO-BkeqjoOijkuKzoOykmOWlqeeGqOunseqjouKgnOWng-GiieK3suWAqeGhiu2KiOGKkeOUmOKhke-JteeAsOmBouSnmO6SuOKxkOmiieykmeeGsuiiq-qgke-HquWkmOSAgeeygCIsIm1lcmNoYW50SWQiOiJtZWxsbyIsImlkZW1wb3RlbmN5S2V5IjoiSUtiYmRkMWI1NS1iZWE3LTRkMzMtOWRkMi0wNGZhZDEwNzFiZDciLCJzdWJ0b3RhbCI6eyJjdXJyZW5jeSI6IlVTRCIsImNlbnRzIjo1MDB9LCJpYXQiOjE3NTI2MTgwOTEsImV4cCI6MTc1MjYxOTg5MX0.tBsJpIMVe0tyeLcu5xfWDKtodFoi44bQKqAckVXq5DI"
28 }
29 '

Response

{
  "paymentId": "f3fc8a34-680b-4b91-905b-1db5628bbb0e"
}

Re-tokenize a saved card number. See tab: Refresh Token w/ CVV
Enable a Saved Card Checkout This endpoint will enable a returning user to complete a purchase with a previously saved card. The returning user will need to enter their CVV before confirming the purchase. Once you’ve retrieved the refreshed card token, pass it into the Saved Card Checkout endpoint. Below is an example request:

Request

1 curl --location 'https://api-sandbox.coinflow.cash/api/checkout/token/testtest' \
2 --header 'accept: application/json' \
3 --header 'content-type: application/json' \
4 --header 'user-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.0.0 Safari/537.36' \
5 --header 'x-coinflow-auth-session-key: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJjdXN0b21lcklkIjoiY3VzdG9tZXIxMjMiLCJtZXJjaGFudElkIjoidHlsZWUiLCJpYXQiOjE3MzQzNjY4NDksImV4cCI6MTczNDQ1MzI0OX0.rxyzFgSZNtIR7KguHyb7MFq2xeDNKH2-3NA49eHH-7Y' \
6 --header 'x-coinflow-client-ip: 64.227.3.71' \
7 --header 'x-device-id: 123456789' \
8 --data '
9 {
10   "subtotal": {
11     "currency": "USD",
12     "cents": 500
13   },
14   "jwtToken": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJkYXRhIjoi456C4oKW26LXgsmg4LiC44Cg6bCF5pWB6LCE7ICz55CX5ICW0ITjgIjsvLjUsOG2j-aLtOuypO6ngeGAgeqEhuiDrOuAgueAie6AgeyAi-i0uETsrovijIQ24aiU6YaR6qq46JSA7LC67Kej7K6C66i246G15YWE6qyc4rGY6ZSp46qH5bC84KaJXHVkYmE45JqZ55uoM1x1ZDg1MO6Lme2MkO6loOKBkOWPu-GKoO6Bo-qDkO6kouGHkOKDqeSomeOAoeqEouqToOWGk--jq-qDqOOvo-GHgO6OhuKMueKmoemZo-SemO2IseaBm-GHkeaBkeaHoOSUq-qHleWUoeyKueifu--kq-GEoO6EqemFouSyueWvpOOIkOWEkOuttO6FouqHoOWBle6UkOWMkeSzk-y3kuqHkOWKolx1ZGUxOeyFneuIhe6Bl-qNjO2Fo-GYkeaHkO6vue6HreuRjOOwv-i5r-6GouqGoueRlOmKn-y6g-eOkOuAkO2InuiTgeaHge2DqOylosuW7ISN3ZnvkYjgooLhqq3qnoXtg4jksKjlmKLhqabqh4zpkazlvJ7pg4DgqYDjlLHtkLzhmKfknoLkg5zqi77mkJfooqroiaLqgJzpkr7lqoLonIPtiqjgsZ3ihpRcdWRmYzbkmKXigabuoLrhjKnkpbLlgr3suIjnurHgoaXkgYPgq7rmtafil4HgpbHsg5DpibvnobnguafrhInuro3ngbbPguGOo-qLhOG4iOG8neC4huSMoeWzpuS8jem_geCuhOqdtOekoO2Sn-2Jp-2Pg-KNhlx1ZDgwY-CmjuCoi-ickO6YjuqmkeGng-aThualkOShlOOukOG9oOimkOyqpOiDs-ykg-SHmuiMse-5lOKUgOKcgOGUoO6zmOqrkeW0h-aes-GXisaz5ruL4Kap2LDsq7_mkJ3pjK_vkpron6XlmLjlsJvksavrmJjso4jeieWuv-OQn-Syj-63vMuBXHVkOGU57IaU5biY76WD3Yrki6jjp6XgoJzjppfmuoztnoruqovsjJvusL3jgavri6jrmKnqrIvhgo7Ng-SLhOWEm-66oOOCjuKUpOaPmO6Ct-SMsOuzsuu9puWLvuGgpuqKk-mQoeC6g-WhhO-4h-K4iO6Cjeq0k-qqkuisnuSEkOSIv-KBjeqCguaotOK-o-ywn-C4quOItuiWtuq8ieuDoeGJhOunpuGGu-itheu6seOVruiDlOqgmuqYhuezvuG5oeavkOaoleyKkeaJuOChi-OMhNCT27vvq6LqmojmgKnroYzklJHikpHijqXljoLloLrguoLlgovhqqnqh4rvqbvmvpHupKBcdTAwMGLukIAiLCJtZXJjaGFudElkIjoidGVzdHRlc3QiLCJpZGVtcG90ZW5jeUtleSI6IklLODZjMDdkM2MtMWRmZi00YTY1LTg0YWYtYThjNTkxNmQyYTZiIiwic3VidG90YWwiOnsiY3VycmVuY3kiOiJVU0QiLCJjZW50cyI6NTAwfSwiaWF0IjoxNzQ2MTQ1NzQ3LCJleHAiOjE3NDYyMzIxNDd9.iCl3jxVihLH6Z2Oq6i1jiKtcyJ3j9kyjT676NzF7Zqs",
15   "token": "411111YJM5TX1111"
16 }
17 '

Response

{
  "paymentId": "0090c04b-1ae8-4672-a108-32874df36f11"
}

Optional Implementation: Get payment by id This endpoint allows your to get details about the payment.

Request

1 curl --request GET \
2      --url https://api-sandbox.coinflow.cash/api/merchant/payments/enhanced/21d842d0-564b-4957-961e-d91ad98aa04b \
3      --header 'Authorization: YOUR_API_KEY' \
4      --header 'accept: application/json'

Response

{
  "info": {
    "firstName": "Dwayne",
    "lastName": "Johnson",
    "email": "customer@email.com",
    "streetAddress": "385 Prospect Ave",
    "city": "Brooklyn",
    "state": "NY",
    "zip": "11215",
    "country": "US",
    "bin": "411111",
    "ip": "35.160.120.126",
    "userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36",
    "expMonth": "10",
    "expYear": "30",
    "ipLocation": {
      "lat": "45.5235",
      "lon": "-122.676",
      "country": "United States",
      "region": "OR",
      "isp": "Amazon.com, Inc.",
      "city": "Portland",
      "zip": "97207"
    },
    "deviceInfo": {
      "ua": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36",
      "browser": {
        "name": "Chrome",
        "version": "131.0.0.0",
        "major": "131"
      },
      "engine": {
        "name": "Blink",
        "version": "131.0.0.0"
      },
      "os": {
        "name": "Mac OS",
        "version": "10.15.7"
      },
      "device": {
        "vendor": "Apple",
        "model": "Macintosh"
      },
      "cpu": {}
    }
  }
}

At this point, you’ve successfully made a purchase with a new card and with a saved card. Next, lets add 3DS for card purchases. Please reach out to the Coinflow team when you’ve reached this step so we can configure 3DS on your account.

Adding 3DS to Card Checkout

Follow the below recipe to learn how to add 3DS to your new card and saved card requests.

Complete Checkout with 3DS Challenge

Adding Chargeback Protection

Add the chargeback protection script to every page of your app. This script allows our provider to analyze user behavior and determine if the behavior could lead to fraud.
- On sandbox, use the test partnerId provided by the Coinflow team.
Pass the chargebackProtectionData object to the new and saved card checkout as well as the below headers. See an example of what the request will look like when you pass chargeback protection data to the new card checkout endpoint.
- x-device-id - Get this after adding the script in step 1
- x-coinflow-client-ip- the payer’s ipv4 address
- user-agent - the payer’s User Agent

Get Credits Authorization Message Get a message which the payer’s wallet should sign - this authorizes them to spend the credit balance.

curl --request POST \
     --url https://api-sandbox.coinflow.cash/api/redeem/evm/creditsAuthMsg \
     --header 'accept: application/json' \
     --header 'content-type: application/json' \
     --header 'x-coinflow-auth-blockchain: polygon' \
     --header 'x-coinflow-auth-wallet: 0xd11cc1D037B49098130BDeB592d468E3fe131240' \
     --data '
{
  "subtotal": {
    "currency": "USD",
    "cents": 200
  },
  "transactionData": {
    "destination": "0x...",
    "type": "token"
  },
  "merchantId": "YOUR_MERCHANT_ID"
}
'

{
  "message": "{\"domain\":{\"name\":\"Coinflow Credits Contract\",\"version\":\"1\",\"chainId\":80002,\"verifyingContract\":\"0xfcc779B1bc3b6C05406244107bAe04B858E7ED38\"},\"message\":{\"customerWallet\":\"0xd11cc1D037B49098130BDeB592d468E3fe131240\",\"creditSeed\":\"mello\",\"amount\":2000000,\"validBefore\":\"1752875597\",\"nonce\":\"0x67db071f7a1810f1e47fffea32087c46a51eaf8554bc9a44d4640f24e3035529\"},\"primaryType\":\"CreditsAuthorization\",\"types\":{\"EIP712Domain\":[{\"name\":\"name\",\"type\":\"string\"},{\"name\":\"version\",\"type\":\"string\"},{\"name\":\"chainId\",\"type\":\"uint256\"},{\"name\":\"verifyingContract\",\"type\":\"address\"}],\"CreditsAuthorization\":[{\"name\":\"customerWallet\",\"type\":\"address\"},{\"name\":\"creditSeed\",\"type\":\"string\"},{\"name\":\"amount\",\"type\":\"uint256\"},{\"name\":\"validBefore\",\"type\":\"uint256\"},{\"name\":\"nonce\",\"type\":\"bytes32\"}]}}",
  "validBefore": "1752875597",
  "nonce": "0x67db071f7a1810f1e47fffea32087c46a51eaf8554bc9a44d4640f24e3035529",
  "creditsRawAmount": 2000000
}

Sign the Message.

const { ethers } = require("ethers");
// Polygon testnet RPC URL
const POLYGON_TESTNET_RPC = "https://rpc-amoy.polygon.technology";
const provider = new ethers.providers.JsonRpcProvider(POLYGON_TESTNET_RPC);
const privateKey = 'PAYERS_WALLET_PRIVATE_KEY';
const wallet = new ethers.Wallet(privateKey, provider);
const message = {
  "domain": {
    "name": "Coinflow Credits Contract",
    "version": "1",
    "chainId": 80002,
    "verifyingContract": "0xfcc779B1bc3b6C05406244107bAe04B858E7ED38"
  },
  "message": {
    "customerWallet": "0xd11cc1D037B49098130BDeB592d468E3fe131240",
    "creditSeed": "test",
    "amount": 2000000,
    "validBefore": "1752875597",
    "nonce": "0x67db071f7a1810f1e47fffea32087c46a51eaf8554bc9a44d4640f24e3035529"
  },
  "primaryType": "CreditsAuthorization",
  "types": {
    "EIP712Domain": [
      { "name": "name", "type": "string" },
      { "name": "version", "type": "string" },
      { "name": "chainId", "type": "uint256" },
      { "name": "verifyingContract", "type": "address" }
    ],
    "CreditsAuthorization": [
      { "name": "customerWallet", "type": "address" },
      { "name": "creditSeed", "type": "string" },
      { "name": "amount", "type": "uint256" },
      { "name": "validBefore", "type": "uint256" },
      { "name": "nonce", "type": "bytes32" }
    ]
  }
}
;
async function signMessage(privateKey, message) {
    const domain = message.domain; // Access the nested `domain`
    const types = { CreditsAuthorization: message.types.CreditsAuthorization };
    //const types = { Permit: message.types.Permit }; // Access the nested `types`
    const messageData = message.message; // Access the actual `message` data
    // Sign the typed data (EIP-712)
    const signedMessage = await wallet._signTypedData(domain, types, messageData);
    // Return the signed message
    return signedMessage;
}
signMessage(privateKey, message)
    .then((signedMessage) => {
        console.log('Signed Message:', signedMessage);
    })
    .catch((error) => {
        console.error('Error signing message:', error);
    });

Send Redeem Transaction

curl --request POST \
     --url https://api-sandbox.coinflow.cash/api/redeem/evm/sendGaslessTx \
     --header 'accept: application/json' \
     --header 'content-type: application/json' \
     --header 'x-coinflow-auth-blockchain: polygon' \
     --header 'x-coinflow-auth-wallet: 0xd11cc1D037B49098130BDeB592d468E3fe131240' \
     --data '
{
  "subtotal": {
    "currency": "USD",
    "cents": 200
  },
  "transactionData": {
    "destination": "0x...", // Whitelisted merchant wallet address
    "type": "token"
  },
  "signedMessages": {
    "permitCredits": "0xd89875c0a956a1b372fa485a90d3d1f5e1b7a6c4d572c47d67df7317c50b73a936bc552cfbbc6cdf260808f103383fe46b2e5b940d0a90465f1fc3c1addbe82b1c"
  },
  "merchantId": "YOUR_MERCHANT_ID",
  "creditsRawAmount": 2000000,
  "nonce": "0x67db071f7a1810f1e47fffea32087c46a51eaf8554bc9a44d4640f24e3035529",
  "validBefore": "1752875597"
}
'

{
  "hash": "0x20eddfe4e37c49c76cc3f6047197e4478bc41d90467279012961a4ef50b30284"
}