Default Implementing server-side components

I've done lots of server-side development in the past, and am attempting to build an android game for the first time.

I've had to build a bunch of server based REST APIs to handle a bunch of things that seem like they would be very common problems you would need to solve in many different types of mobile games.

I felt like I was rebuilding the wheel and that there should be an out-of-the-box solution for most of the things that I ran into. But, I did a bunch of research and couldn't find anything out there that I liked much and which wasn't very expensive.

The types of server-side things I needed to build were:

- Server-side execution of certain game code (I can go into details why I wanted to run this code on the server-side if people are interested).

- Server-side in-app purchase validation.

- Server-side storage of certain game data (I can also go into details why I did this, if you like).

An example of an out-of-the-box solution would be a service that provided REST APIs on cloud servers managed by a third party company where there was a small subscription fee to access your REST APIs.

I probably should have spent more time researching this and asking questions before rebuilding the wheel. But I have lots of server-side dev experience so it didn't take me that long to build the components I needed.

Now I am wondering whether other folks have had similar experiences rolling these types of things on their own, or if there are any out-of-the-box solutions that people like that maybe I should be using instead of my homegrown solution.