An API will allow you to have one main system which interacts with your data. You can then have other presentation layers on top of this, e.g. a website, a mobile app or a chatbot etc. I will create you a robust efficient and highly scalable API in the latest Asp.Net technologies to fulfil your needs. If you add on the creation of a database, I will design & build a new database or update your existing database, all in Azure or the ClearDB cloud, using your requirements. What frameworks / languages will you create the APIs in? What is Swashbuckle? Why should I purchase this service from you? I have been architecting/developing complex business critical software within Fortune 500 companies for many years.