I am looking for a Backend as a Service (hosted solution) that provides a free starter plan. Firebase provides the ideal features I am looking for however it appears they have no C# client that supports their authentication system or any Python client at all. (Correct me if I am wrong)

Is there a Backend as a Service that provides the same features as Firebase (Auth/User Management, Database, Realtime updates) that has support for Python, Android, iOS and .NET/C#?

I've also been looking at parse-server and although it does have a 1st party supported .net client and a fairly good python client neither of them support the newly released "live query" system which provides the realtime updates I am looking for.

Any ideas? Thanks!

I'm going with no. I can't guess why C# but that could push a system into OSes and systems that cost in license fees and promptly removes your "free" requirement.

My advice is to forget any attachment to a language here and find your service that meets your price targets then create your apps using whatever OS and language works.

It's good to learn other languages.