Get USDC Authorization Message (EVM only)

Gets the USDC authorization message to be signed by the customer for dual-source payments. The signed message allows the customer’s USDC to be used alongside credit card payment.

This is only necessary for EVM chains when using customer USDC + credit card payment.

Authentication

x-coinflow-auth-session-keystring

The session key generated for the end user - see https://docs.coinflow.cash/api-reference/api-reference/authentication/get-session-key

x-coinflow-auth-walletstring

The web3 wallet of the end user - see https://docs.coinflow.cash/api-reference/api-reference/authentication/get-session-key

x-coinflow-auth-blockchainstring

The blockchain associated with the end user - see https://docs.coinflow.cash/api-reference/api-reference/authentication/get-session-key

Request

This endpoint expects an object.

amountobjectRequired

paymentIdstringOptional

Optional payment ID for generating unique nonce

Response

messagestring

EIP-712 message to sign

messageDataobject

Structured message data for transparency

$	curl -X POST https://api-sandbox.coinflow.cash/api/checkout/evm/usdc-authorization \
>	-H "x-coinflow-auth-session-key: <apiKey>" \
>	-H "Content-Type: application/json" \
>	-d '{
>	"amount": {
>	"cents": 2500
>	}
>	}'

1	{
2	"message": "Authorize spending of 25.00 USDC for payment ID 12345abcde on CoinFlow platform.",
3	"messageData": {
4	"nonce": "0x9f8b7c6d5e4a3b2c1d0e",
5	"validBefore": "2024-07-01T23:59:59Z",
6	"validAfter": "2024-06-01T00:00:00Z",
7	"value": "25000000",
8	"to": "0xA1b2C3d4E5F678901234567890abcdef12345678",
9	"from": "0xB2c3D4e5F678901234567890abcdef1234567890"
10	}
11	}