Every SaaS kit forces a trade-off. .NET kits have no mobile. Flutter kits lock you into Firebase. Next.js kits give you neither. LaunchKit combines a production .NET 8 API with Flutter (web, iOS, Android) in one codebase. Includes: JWT + 2FA + Passkeys, Stripe billing, multi-tenant orgs, AI streaming (OpenAI/Claude/Gemini), admin panel with impersonation, blog CMS, helpdesk, 5 languages + RTL, Docker, CI/CD, and 111 tests. Live demo included. Set up in 10 minutes.