B2B SaaS MVP in 11 days

Built a niche CRM for fitness coaches — full auth, billing, dashboard, mobile-responsive. Stack: Next.js + Supabase + Stripe.

Founder closed 8 paying clients in the first month.

0

Problem

Founder had eight pre-orders for a fitness-coach CRM but no product. Hiring a dev shop quoted 12 weeks and €60k. They needed to ship in two weeks.

Users

Public SaaS — 30+ paying fitness coaches across UK and DE

Key flow

1Coach signs up, adds clients and assigns a training program
2Clients receive a check-in link each week and log progress
3Coach reviews on mobile, sends adjustments inside the app

What I built

Next.js app on Vercel with magic-link auth via Supabase
Client + program + check-in models with per-coach data isolation
Stripe Checkout + customer portal for self-serve billing
Mobile-first UI — coaches use it on phones between sessions

Limits

Single-coach accounts only — multi-coach team plans queued for v2
Reporting is basic — exports CSV, no built-in charts yet

B2B SaaS MVP in 11 days

AI tools used

Cursor
Vercel
Supabase

@nuria.vidal