Guidance on creating a custom Razorpay Payment Gateway extension

[mailozar]

I am developing a Razorpay payment gateway for MailWizz v2 and would like some clarification to ensure I build it correctly and in line with your system.

Could you kindly confirm the following:

1. Base class / interface:
   Which class should a custom payment gateway extend or implement in MailWizz v2 (for example, PaymentGatewayAbstract, BasePaymentGateway, or similar)? If possible, please share the exact file path and class name used by the built-in gateways (e.g., PayPal or 2Checkout) in the current version.
2. Required methods / signatures:
   What are the mandatory methods that every payment gateway must implement (e.g., getName(), renderPaymentForm(), processOrder(), getConfirmationUrl(), etc.) in order to be detected and listed under Backend → Payment Gateways and in the customer checkout?
3. Developer resources:
   Is there any official documentation, guide, or sample code for building a new Payment Gateway extension (not just a generic extension), so it appears alongside PayPal/2Checkout in the Payment Gateways manager?

My main goal is to ensure Razorpay is implemented as a first-class MailWizz payment gateway so it can be configured and used just like PayPal/2Checkout.