Been using Claude Sonnet 4 for a web app that's using React, Mantine, Vite, and a NoSql db.
Frankly, it's been incredible. The app is not complicated by any means. It's a really simple CRUD app for tracking animals (what farm animals are on, breeds, medical history, birthing schedule, etc.), but when I've provided mockups, it's done a surprisingly good job to at least get me 80%-90% of the way there.
I think it has to do with my tech stack honestly. Well built components can get an individual developer with poor FE experience quite far. I think it's the same for AI as well at this point.