Metadata#

metadata is an optional JSON object you attach to a payment. Cartino Pay stores it verbatim and returns it in every payment response and webhook, so you can correlate the outcome with your own records without an extra lookup.

"metadata": {
  "user_id": 123,
  "plan": "pro",
  "cart_id": "c_9f8e7d",
  "mobile": "09121234567"
}

Limits#

• Object with ≤ 50 top-level keys
• ≤ 4 KB when JSON-encoded
• Any JSON value types; nesting allowed

Special keys#

Some gateways accept extra hints. When present, Cartino Pay forwards these keys to the gateway if it supports them:

Everything else is opaque to Cartino Pay and to gateways.

Rules#

• Do not store secrets, tokens, passwords, national IDs, or full card numbers in metadata.
• Do not rely on metadata as the sole link to your order; also persist payment_id on your side.
• Metadata is included in the idempotency fingerprint: sending a different metadata object with the same Idempotency-Key yields IDEMPOTENCY_CONFLICT.
• Metadata is visible to Cartino Pay administrators in the transaction view.