Ask HN: Getting started with a API/Software as a Service business

Dear HN,

I had an idea for a API/Software as a Service website and I would like to give it a try.

Nothing really special, everyone can try a small number of free API calls, or buy an API key for getting additional API calls per month.

I already have the C++ code for the software I want to sell as a service, which has already been sold in the past in the good old way (I mean: user pays for a license). However, being an old school programmer my knowledge of web languages and web technologies is quite limited.

My question is: where do I start? Are there ready-to-use stacks I can use for my website? In particular regarding the payments, the management of API key, rate limiting and interfacing with the existing code.

Of course I tried Googling, but the landscape looks quite confusing to me...

I would be comfortable programming in Python, but I am using this project to learn something new, so even a language I don't know will be OK!