Retrieve the list of conditionally required or applicable fields for a specific transfer destination together with their constraints.

:::note [Note] This feature is not available in Sandbox. :::

When creating a payment via the /pay endpoint, certain fields (such as transfer_reason_code, charge_bearer, or exchange_reason_code) become required or applicable depending on the source account, destination corridor, and business profile. This read-only endpoint allows you to discover these contextual fields dynamically, along with their validation rules and available options.

:::tip A destination corridor is a specific combination of bank country and currency representing a supported payment destination (e.g. GBP to GB, USD to US). :::

Only the fields relevant to the specific context are returned. Universally required fields (such as amount, account_id, receiver, and request_id) are always required and are intentionally excluded from this response.

For more details, see the guides: Check transfer field requirements section in Bank transfers or Card transfers.