Here’s one we did earlier
Birchalls food services had a requirement for a payment interface for their Microsoft dynamics system, They already have a shop called Birchall Order Mate where account customers could order their products , but there was no system to allow the account holders to manage their payments.
We were asked to provide a solution.
We created a solution that allowed the account holders to view their accounts, make decisions on what needed to be paid through to providing the services enabling the payments to be made directly into their Merchant account.
We also optimised the site to work on mobile phones and ipads too.
Very briefly, if you’re interested, the technology we used was Python /django/ cerley/redis for the programming environment , Linux/Nginx/Pfsense for providing development platform Github for CI/version control and AWS/docker for production environment. We also had to collaborate with the customers Microsoft Dynamics API developer and the people developing the Ordermate system.