I had a little bit to do with custom tools when it was mostly .Net/C based and built 1-2 tools in the yxi era with python. Basically all the custom tools now are python with a front-end, I believe still HTML (maybe react-js more likely), but not sure on that currently as I haven't played with any of the SDK's for a couple of years. I haven't seen a custom tool not written in python for a good while, so plausible that only python is supported now.
One of the biggest challenges to getting started is finding the correct, current and best resource. If you don't understand environments etc, that can be a little challenging to get the right starting point. All in all, its not a "This is how I learn coding", but it's not too hard.
If you don't understand setting up Python environments and how they work, then you'll have a little learning to do. As well as pointing the code to the relevant endpoints. However, if you already write code and have the setup, it's not hard, there's a few guides floating around on the community. If you haven't built a program/app before then go slowly as you'll need to do different things, like assigning outputs and possibly assigning memory or dealing with environment variables, but nothing too difficult. Alteryx has put a bit of effort into making an SDK that can be used by LOB users.
You can find the SDK info:
If you are just talking about macros that get productionised, then that's a different story, and just Alteryx experience that makes it easier.
As with any productionisation, it's 80-20 rule, you can create something for you to use, but to create it for others and how others want to use it takes skill and time. If taking this route, I advise taking into account how many people on the fringes of your use case are going to use it and expanding to cover those as well. And also, be prepared to address questions in the marketplace chat, the most successful tools are from people that respond and update when issues are found, and they will be found.
