Hi, I'm new to stencyl, but I haven't seen this solution mentioned in the forums, so it may be of use to people.
I'm working on a game with a multiplayer system and I'm using
www.parse.com to power it.
It's a really cool backend system that allows you to create databases on the fly.
I'm using the REST api, which only need the existing Stencyl url get/post blocks.
It's free to open an account, you only need to pay if your usage is pretty high volume.
Parse can also handle push notification and server side code, as well as a whole load of other features such as filtering by location, sign in via facebook etc.
The REST api is good enough for me, but maybe someone with more coding skills than me could built a block to work directly with the API though?