I can clearly see that small utility products with a well-proven market need is an obvious choice for indie hackers. Podcast hostings, email marketing tools, SMM automation, monitoring APIs, etc.
However, I was wondering if there are good examples of small businesses with more sophisticated core components like real machine learning, distributed computing, big data, any other "hard tech".
One example of a small, AI-driven tool I can think of would be Krisp, but they aren't really indie.
Anything comes to mind?