I want to make my own UPI automatic payment gateway

I want to make my own UPI Automatic Payment gateway in php like this:- https://youtu.be/FYy1TU3QTFE , user make payment and after payment it automatically deterct the payment is sucessful or pending or failed. You can use BHIM API or any other API for this and most important thing I want to have 0 transaction fees for every transaction. My total budget 7k-8k.