how to use free cloud database with android app?
Now there are a lot of cloud providers , providing solutions like MBaaS (Mobile Backend as a Service). Some only give access to cloud database, some will do the user management for you, some let you place code around cloud database and there are facilities of access control, push notifications, analytics, integrated image and file hosting etc.
Here are some providers which have a "free-tier" (may change in future):
- Firebase (Google) - https://firebase.google.com/
- AWS Mobile (Amazon) - https://aws.amazon.com/mobile/
- Azure Mobile (Microsoft) - https://azure.microsoft.com/en-in/services/app-service/mobile/
- MongoDB Realm (MongoDB) - https://www.mongodb.com/realm
- Back4app (Popular) - https://www.back4app.com/
Open source solutions:
- Parse - http://parseplatform.org/
- Apache User Grid - https://usergrid.apache.org/
- SupaBase (under development) - https://supabase.io/
As Wingman said, Google App Engine is a great solution for your scenario.
You can get some information about GAE+Android here: https://developers.google.com/eclipse/docs/appengine_connected_android
And from this Google IO 2012 session: http://www.youtube.com/watch?v=NU_wNR_UUn4