A JavaScript library that brings Processing to the web browser, started in 2013 by Lauren Lee McCarthy. Much browser-based and on-chain generative art is written in it.
I was in New York working on how to internationalize the p5.js website and through that I met Lauren relatively toward the beginning of her working on the p5 project.
Maya Man, Maya Man on Generative Meaning
You have things like Processing and p5.js that are good enough for a lot of artists. Fewer artists are needing to develop custom software in order to create their work.
Tyler Hobbs, Tyler Hobbs on Algorithmic Aesthetics