How long does it take to launch a MERN SaaS?

A focused MERN SaaS MVP launches in 8 to 12 weeks with two engineers. A mid-sized MERN SaaS with multi-tenancy, Stripe billing, feature flags, and a polished admin panel lands in 4 to 6 months. Enterprise MERN SaaS with SSO, custom domain support, compliance features, and white-labelling runs 8 to 14 months. Timelines are protected by locking scope in week one. We do not give timelines before seeing the spec.