Supabase supports Tailwind CSS

Supabase is the Postgres development platform. You sign up and start building without installing anything, and you get a full Postgres database plus the things you'd otherwise wire up yourself: user signups and logins, auto-generated APIs, realtime subscriptions over websockets, file storage, database functions, and a vector toolkit for embeddings. If you've never touched Postgres, you can treat it like a simple table store and grow into the rest. If you're a veteran, the whole database is there with full privileges.

Every part of Supabase is open source. When a good tool already exists under a permissive license, they use it. When it doesn't, they build it and open source it themselves. They also employ maintainers, sponsor projects, and invest in the businesses behind the tools they rely on. So you can inspect, run, and host every part of the stack yourself.