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