I have a web application which is a pretty standard SAAS database driven app. I have a few customers asking for iOS or Android versions of the app. Is it better to build an API on the web app which is then used to drive the native mobile apps UI? This would be simplest but mean the mobile apps are not 'stand alone'. Alternatively I could try and implement a full mobile solution that then synchronizes with the web app somehow. This would be much more work as all the business logic needs to be build into the mobile apps rather than behind the API.
What is standard practice for this kind of thing?