# Payment Rails
source: https://developer.mastercard.com/ob-accept-payments/documentation/developer-support/production/payment-rails/index.md

Note: In addition to the specifications in the API Reference, you are required to follow the payment rail requirements depending on your region and the available payment methods.

The scope of our Open Finance payment APIs does not extend to the payment execution. For example, we will enable sending payment initiations to a participating bank or financial institution and enquiring for the result. In the background, the bank will execute the payment through one of their existing payment rails (schemes), such as Faster Payments in the UK, or SEPA / SEPA Instant in Europe, and so on. Each of these rails usually has their own region availability, participants, set of rules, restrictions, message-format implementations and expected data set.

Some of these restrictions need to be applied to the input we get from you to ensure end-to-end flow. AS such, we have introduced the concept of Payment Rails to the API.

Specifically, the rails control:

* Available Use Cases
  * Refer to [Use Cases](https://developer.mastercard.com/ob-accept-payments/documentation/use-cases/index.md) for detailed information.
* Available Providers (Banks and financial institutions)
  * Refer to [Supported Payment Rails](https://developer.mastercard.com/ob-accept-payments/documentation/developer-support/production/supported-payments-rails/index.md) for detailed information.
* Required fields, field length and additional restrictions (for example, Currencies)
  * Refer to the [API References](https://developer.mastercard.com/ob-accept-payments/documentation/api-reference/index.md) for detailed information.

When a payment rail is selected in the API request, these restrictions are applied automatically and will impact what you can send in the request, and what the Consumers can see in the UI flow (such as banks available for selection).