I have immense experience in developing a web services API for Web or mobile application development. A web service provides functionality similar to the business logic layer in the application and it is not tied to User Interface and can be reused for different cases. Web services are built with standards like Restful API via JSON. The web back-end can be built in any programming language (like PHP-Symfony/Python-Django) and web service layer can be developed on that. The web application needs to be hosted on a server and you will need to factor that as part of budgeting. Same webservice can be used for any mobile platform, It can be either Android, Apple or Windows. So no need to worry to create different API for each platform. Talk to me before you order my gig. Looking forward to build long relationship. Thank You