Is there a phone app?

There is no app to install. Coasting runs in your phone's browser, and the whole inbox works there.

See every conversation, with the same Open, Pending, Resolved and Closed filters as on a computer
Open a conversation and read the whole thread
Type a reply and send it - it goes to the customer exactly as it would from a desktop
Search, and switch between your own conversations and the whole team's

Add coasting.app to your home screen and it opens like an app. Nothing to download, nothing to update, and you are never waiting on an app store.

What you do not get on a phone: push notifications. If you want to know when a customer is waiting without checking, Coasting emails your whole team once per conversation as soon as the AI hands one over, so the alert arrives wherever you read email.