Include trail period (1 week, 2 weeks, 1 month or free) options into the payment plans. So that it is visible to the paying client

I'm starting a referral program and need to include a field for customers to enter a referral or promo code

SuperPay operates in multiple regions and we must be able to localize payment pages for different countries

The ability for the customers to set quantities when paying e.g if it's an event and the same person wants to pay for multiple tickets

This may prove useful for a number of our customers that have integrations already setup for a secondary email.

The ability to create coupon codes allowing customers to apply them at checkout.

Allow the ability to collect fields from customers when completing payments for one-time and recurring. Be able to send the data for that field via a URL query parameter?

For high value, international payments billing address collection is essentially mandatory. It reduces "Do Not Honour" declines from the cardholders bank by ~50%. It's less important for domestic transactions, but banks are increasing looking at more metadata for international when deciding whether to accept or decline a transaction. You should have the ability to collect a billing address and pass this to Stripe correctly.

Instead of sending payment link emails coming from Che at SuperPay, it would be nice to have notifications sent to clients from my company.

The ability to change and modify the text in emails