Repeaterbook offers a smartphone app for iOS, Android, and Amazon Kindle. You can download the app from the various stores:
The app is an “offline” app, which means it does not require a data connection to operate, once you have downloaded the app. It does require GPS to work.
The benefit of the offline architecture is the ability to locate repeaters near you without a data connection. In a true emergency or during backcountry travel, a data connection may not be available to you. The app will still function.
The app is updated about every two weeks with the database changes. Although the Repeaterbook.com web site is updated daily, the app doesn't immediately receive the updates. This is due to the offline architecture. So, if you see that a pending update is available for the app, you should download it immediately to receive all the latest repeater information updates.