curl --request POST \
  --url https://api.circle.com/v1/exchange/stablefx/signatures/funding/presign \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "contractTradeIds": [
    "10",
    "11",
    "12"
  ],
  "type": "maker",
  "fundingMode": "gross"
}
'

{
  "deliverables": [
    {
      "currency": "USDC",
      "amount": "<string>"
    }
  ],
  "receivables": [
    {
      "currency": "USDC",
      "amount": "<string>"
    }
  ],
  "typedData": {
    "domain": {
      "name": "Permit2",
      "chainId": 11155111,
      "verifyingContract": "0xffd21ca8F0876DaFAD7de09404E0c1f868bbf1AE"
    },
    "types": {
      "EIP712Domain": [
        {
          "name": "name",
          "type": "string"
        },
        {
          "name": "chainId",
          "type": "uint256"
        },
        {
          "name": "verifyingContract",
          "type": "address"
        }
      ],
      "TokenPermissions": [
        {
          "name": "token",
          "type": "address"
        },
        {
          "name": "amount",
          "type": "uint256"
        }
      ],
      "SingleTradeWitness": [
        {
          "name": "id",
          "type": "uint256"
        }
      ],
      "PermitWitnessTransferFrom": [
        {
          "name": "permitted",
          "type": "TokenPermissions"
        },
        {
          "name": "spender",
          "type": "address"
        },
        {
          "name": "nonce",
          "type": "uint256"
        },
        {
          "name": "deadline",
          "type": "uint256"
        },
        {
          "name": "witness",
          "type": "SingleTradeWitness"
        }
      ]
    },
    "primaryType": "PermitWitnessTransferFrom",
    "message": {
      "permitted": {
        "token": "0xTOKEN",
        "amount": "1000"
      },
      "spender": "0xffd21ca8F0876DaFAD7de09404E0c1f868bbf1AE",
      "nonce": 42,
      "deadline": 1735689600,
      "witness": {
        "id": "10"
      }
    }
  }
}