I'm a developer myself. I just need a proxy server that have API. I'll do the rest myself.I see your needs here. I happened to code this kind of software exactly per your requirements some years ago. There is no publicly available solution per your requirements. I never released those codes because I know the value.
Your only option is to hire a freelancer for this job and make sure he is skilled enough.
Thank you, I'll check it.you should use 3proxy from here
I've already checked it.You can have a look at Dante here
Very reliable proxy server
I couldn't find how can I manage users with php in it's documentation.you should use 3proxy from here