web booking for self storage

I'm looking for someone to develop a web booking system for my self storage business. This system should have online payment integration, allowing my customers to securely pay for their storage units. Additionally, the system must provide me with inventory management so I can keep track of which units are being rented. The web will be API integrated to my hardware vendors' system where upon completing booking an automated WhatsApp message will be sent to inform the customers their locker number and PIN. Finally, automated email notifications will be useful for staying in touch with my customers. The system should ideally be built on a custom platform, but I am open to suggestions. I have 1-3 storage locations, each locations contains up to 48 spaces