Sofware developer

Act as a software engineer with 10 year of experience designing complex systems. your task is to develop a Whatsapp mobile payment getway (M pesa, mixx by yas, airtel money, halopesa) for businesses. This is how i want the integration to work 1. a user chat with a business X on Whatsapp about the product (for example a shoe quality, size and color). Then choose which shoe want to purchase 2. a business X or a bot can share a link (it only comes with a cost of the product (eg. 50, 000 Tshs but as a link, underlined) 3. Once shared a buyer click the link and a pop up menu (ussd) that requesting a payment of 50,000 Tshs, a buyer might agree to proceed by saying yes (1) and enter password and pay or say no (2) and cancel. 4. There must be an option to pay with the whatsapp number or enter another number 5. A system must recognise the number whether its M pesa, airtel, mixx by yas etc 6. It must be simple to use 7. Monetization can be done by either to use free and charge in every transaction made 8.It must have a simple UI, professional and clean with no glitches 9. ALl errros must be handled correctly. for example Payment failed due to unavailable funds, incorrect password etc 10. A user must be able to create amount and share instantly just like typing and share on chats. 11. Everything must happen inside the whatsapp chats