Do you have a mobile app?
We don't have an app or API, but you can access your LGL account from any mobile device using any browser, and can add constituents/update records. That said, the application is not optimized for the phone screen, so there is some scrolling left and right required. Searching on constituents and pulling up their info is no problem, but there is some functionality that would not be easy to do on the phone, such as multi-query searches, reports, or importing data.
For contact reports, some of our customers have created a web form using LGL Forms which they use to submit those notes. Those submissions can be integrated to flow into your LGL account to update or create records.