Canton example

Execute a Carbon card top-up from a Canton wallet through the Zebec Partner API.

Use this flow for a quote whose payment.chain is CANTON. The Partner API does not provide a Canton payment SDK, so submit the quote-defined transfer through your Canton wallet or ledger API.

Begin with the shared top-up flow, including preflight. For Canton, buyerAddress is the public signing key used by your integration.

Request and execute the quote

GET /partner/v1/topup/quote?amount=100&currencyCode=USD&sourceChain=CANTON&sourceTokenMint=<token-id>
Authorization: Bearer <accessToken>

Use the quote's network, token identifier, base-unit amount, and receiving instructions unchanged. Save the ledger transaction identifier as txHash only after the transfer is confirmed by your Canton integration.

Sign and submit

Sign the exact UTF-8 signingMessage from the quote. publicKey and buyerAddress must be the same Canton signing key after whitespace and an optional 0x prefix are normalized.

{
  "quoteId": "<quote-id>",
  "receipt": {
    "deposit": {
      "txHash": "<confirmed-canton-transaction-id>",
      "buyerAddress": "<canton-public-signing-key>"
    }
  },
  "userSignature": {
    "signature": "<base64-base58-or-hex-signature>",
    "publicKey": "<canton-public-signing-key>",
    "scheme": "canton",
    "cantonAlgorithm": "ed25519"
  }
}

ed25519 is the default. For ECDSA keys, set cantonAlgorithm to ec-dsa-sha-256 or ec-dsa-sha-384 and send the ECDSA signature in DER format. Do not use an account identifier in place of the signing public key.