We are developing a website alongside an android app version with SDK, we are coding the website in standard PHP and creating a RESTful Web Service for our android app. The question is how our app could influence on our website's rank?
e.g: The most if not all of the Instagram's users use the smartphone app version not the actual website, however their website's rank in Alexa is 35 in world. Isn't the ranking based on some tools that are hidden in browser's toolbars extension!!?
Your RESTful Web Service will have no effect on your websites search rank.
The Alexa rank is based on a sample of internet users who use their toolbar. You SDK will not interact with their toolbar so will not register any hits with them.
While the Instagram website looks simple, it offers lots of information such as a blog, API information, help and more.