What are you building using Generative AI?

Hey everyone, I am looking to see what makers are building Generative AI services such as GPT, Midjourney, etc. Have you built something that is being used by users actively? Making prototype is one thing but taking that to users is another big leap. I want to understand the challenges in productionizing the generative ai-based apps, help me with your feedback - i.e. what challenges to expect in productionizing generative ai-based apps.