An MVP is not "a small version of the product". It's the minimum you need to test the critical assumption about your business. This definition is often ignored, and the result is MVPs that look like 60% of the final product, take 6 months to build and end up unused.
Here are the five most common mistakes we've seen working with entrepreneurs building their first SaaS product.
1. Too many features in the MVP
The classic mistake. "We need user accounts, billing, dashboard, settings, notifications, mobile app, admin panel, integrations". No — you don't need all that to test the main hypothesis.
Frizmo Platform, which today is a comprehensive booking platform, started with three things: a salon page, a booking form and an email notification. No billing, no admin panel, no mobile app. The idea was to test whether real salon owners would register their business if it had a good online presence.
2. Building an admin panel before having users
We often see SaaS projects where the first 2 months go into building an admin panel for managing clients, products, billing, statistics. When they launch — they have no users, because the entire month of work went into internal tools.
For your first 10-50 clients, your admin panel is database client + spreadsheet. Seriously. Manual SQL queries and Google Sheets. It's not elegant, but it works and saves 200+ hours of development that can go into features clients actually see.
3. Premature scaling in architecture
You don't need Kubernetes. You don't need microservice architecture. You don't need event queues. For the first 1000 users, Postgres + Node.js + Vercel will handle without breaking a sweat.
We've seen MVPs built with 5 microservices, message queues and elaborate CI/CD pipelines that never even reached production. All that complexity was for "future scale" that never came.
- One monolith app — perfect for the first 10K users
- One Postgres database — easily supports millions of records
- Vercel or Railway for hosting — no Kubernetes
- Simple REST or tRPC APIs — no need for GraphQL in MVP
4. Custom auth instead of a ready-made solution
Authentication is a trap. It looks simple — login, register, password reset. In practice there are dozens of edge cases (rate limiting, password policies, account recovery, session management, email verification, social login).
For MVP we recommend Clerk, Supabase Auth or Auth.js. Free tiers are enough for the first thousands of users, and you save 40-60 hours of development plus endless security updates later.
5. No telemetry from day one
You launch the MVP. After 2 weeks you want to see how it's used — but you have no data. You didn't set up analytics from the start, and now you either know nothing, or have to wait for new users to collect data.
The minimum from day 1:
- Plausible or Umami for page views and conversion funnels
- Sentry for error tracking — 5 minutes setup, priceless when something breaks
- PostHog or Mixpanel for event tracking — which features get used
- Database queries for critical metrics (signups, active users, retention)
Conclusion
MVP isn't about writing code. It's about discipline — what you DON'T build, what you DON'T optimize, what you DON'T scale. The goal is a learning loop, not a perfectly polished product.
Frizmo Platform didn't start as a platform. It started as a page for one salon, taking reservations through a form. The entire current architecture — multi-tenant, billing, website builder — was built after we knew the problem was real. That's the right order of work.