An open-source Next.js SaaS starter with Mailtrap wired in as the email layer — auth, Stripe billing, multi-tenancy, and transactional email are all pre-built. It's blank-slate scaffolding, not a working product, built for learners, indie hackers, weekend builders, and juniors copying patterns — not production-grade engineering teams. Clone it and drop your own product logic on top within an hour.