SarvStack is a production-grade SaaS boilerplate for TanStack Start: Supabase auth with documented RLS patterns, Polar merchant-of-record billing (EU/UK VAT handled out of the box), shadcn/ui design system, and CLAUDE.md conventions so Claude Code and Cursor extend your codebase safely. One purchase, lifetime license. The site itself runs on the kit — auth and checkout are live demos.
