AppWarp is a product made to achieve real-time communication between connected players. AppWarp also provides some readymade server-side features such as Room/Lobby management, Matchmaking, Turn management etc. It does not store any information of the players o the server side.
From your requirement, I believe you need to store the player information on the server side. You can use our BaaS product App42 Cloud API which provides 800+ API to manage with backend related features such as User Management, Storage Service, Push Notification, Leaderboard, Avatar Management, Achievement, Gifting and much more. Check out its Dev Center for more details.
Regarding server-side customisation, it completely depends on your game requirement and how you want to achieve it. If any of your game features require server-side coding, let us know we can provide the right approach to do it.
Let me know if you have any further queries, I will be happy to help.