As the title implies I am trying to code an app and am looking for something like IntelliJ to code it with unfortunately every single one that I find requires that I have a license to use it and I would like to find one that does not require me to pay up front. I am fine paying a percentage of the profit that I make from the app but I simply do not have enough money at the moment to pay a set amount so if you could tell me about something like this then I would massively appreciate it thank you in advance.(also if you could tell me the technical term for something like IntelliJ then that would also be greatly appreciated thank you).

I wanted to start programming Minecraft mods but I can't find the Community edition. A tutorial that's two years old showed that it's on the download page when you scroll down a bit. But now I can't see it anymore.