Since two years I am working on a development tool named GameRocket (www.gamerocket.io).
It provides a highly flexible game structure including actions, items, quests, achievements, leaderboards... all in the cloud.
It was tough at first to provide indie dev a solid structure to fasten their projet development. We try to stay as close as we can of what game dev can expect, but we are listening to requests (like the team development system or the cross game compatibility).
For one year we have used GameRocket for our in-house projects. After 1 year of correction and tuning the service is now open to the public.
We are providing SDK usable with the major languages (Ruby, Unity, C#,…).
To help the understanding of what can be done, there is a small but complete game projet using Java and Php SDK (https://www.gamerocket.io/docs/php/example/step0)
Hope you like and support it.