Building a SaaS MVP with a Freelance Developer in France: 2026 Method

You have a SaaS idea that has been running in your head for months. You hesitate to bring in a CTO, to raise funds, or to spend six months coding on your own a product no one has yet validated. Meanwhile, a less technical but faster competitor can ship an MVP in eight weeks and capture the first users. Speed of validation has become the main success variable of a SaaS in 2026.

I run CODRUM (SIREN 103 982 005, RCS Évry), a research firm in geomatics and web development based in Morsang-sur-Orge (91390). The firm works with startups and solo founders who want to validate a SaaS idea without burning 50 000 € in development before even reaching a first paying customer. Here is our method, refined project after project and informed by ongoing research within the Master 1 Geomatics G2M programme on modelling and data analysis.

MVP: what stays in, what gets cut

MVP stands for Minimum Viable Product. Not a prototype, not a marketing site, not a patched-together Notion: a working product, just complete enough to validate one single hypothesis, drawn from the trilogy of problem, solution, willingness to pay. If you do not know which of the three you are testing, you are not ready to write code.

What we keep in the MVP: authentication (Supabase Auth, free up to 50 000 users), one or two business workflows at the heart of the value, Stripe payments from day one, lightweight analytics tracking (Plausible or Posthog), and a live feedback widget (Crisp or Intercom). Five building blocks, no more.

What we cut without hesitation: complex multi-tenant, admin dashboards with ten views, internationalisation, native mobile application, two-sided marketplace, gadget AI features. All of that comes after product-market fit, not before. Every feature added to the MVP delays the go-to-market by one to two weeks and increases the future technical debt.

Minimalist stack for a 6 to 8 week MVP

The stack I use on my SaaS MVPs is deliberately narrow, battle-tested, and free or nearly so up to the first thousand paying users.

Frontend: React 19 + TypeScript + Vite + Tailwind CSS v4. This is the fastest combination to develop with today, paired with a massive ecosystem and ready-to-use components (shadcn/ui, Radix). Backend and database: Supabase (managed Postgres, auth, storage, real-time), hosted in Europe, GDPR compliant, free up to 500 MB of database and 50 000 monthly active users. Payment: Stripe Checkout and Customer Portal (four hours of integration, zero maintenance). Hosting: Vercel (free up to 100 GB of bandwidth).

Tracking: Posthog (self-hostable, GDPR-friendly, free up to one million events per month) or Plausible if you only need visit counts. Live feedback: Crisp on the free plan is more than enough for the first six months. Total infrastructure cost for an MVP up to 500 paying users: around 0 to 50 € per month.

The classic pitfalls of a first SaaS

Across the MVPs I have seen fail or stall, five mistakes keep coming back. Avoid them and you will save three to six months.

Pitfall 1 — Feature creep. In every conversation with a prospect, you will feel tempted to add "just one small extra feature". Learn to say no to 80 percent of requests during the MVP phase. A product that does one thing perfectly beats a product that does ten things averagely ten times over.

Pitfall 2 — Over-engineering. Microservices, Kubernetes, Kafka, federated GraphQL for ten users: this is self-sabotage. A React + Supabase monolith comfortably handles 10 000 users and can be refactored the day you actually need to.

Pitfall 3 — No payment from day one. A free MVP validates no economic truth. The only proof that a problem is worth solving is a human pulling out a credit card. Add Stripe in version 1, even at 5 € per month.

Pitfall 4 — No tracking. If you do not measure activation, 7-day retention and signup funnel, you are iterating blind. Posthog plugs in within 30 minutes and changes your decision making.

Pitfall 5 — No live feedback. A chat widget on the dashboard produces ten times more insight than a monthly survey form. Crisp, Intercom, it does not matter: your customer must be able to tell you "this is broken" in two clicks.

The short cycle: validate, iterate, scale

The right rhythm for a serious SaaS MVP comes down to four phases. Build (6 to 8 weeks): we code the working version 1 with the five building blocks listed above. Private beta (4 to 8 weeks): 20 to 50 invited users, payment turned on, structured weekly feedback, fast iterations. Public launch: Product Hunt, LinkedIn, targeted communities, light cold outbound. Iteration toward PMF: three to six additional months on average before reaching healthy retention and a stable conversion rate.

Budget, timelines and ongoing support

For a solid MVP delivered turnkey by me, expect from 4 000 € for a scope covering auth, one or two core workflows, Stripe payments and analytics. For a more polished version (from 8 000 €), we add a clean analytics dashboard, transactional emails (Resend), guided onboarding and a lightweight admin panel. The final price depends on the functional scope and the level of customisation: a tailored quote is sent within 48 hours of a free initial call.

For a full breakdown of every service and price range, see the Services & Pricing page.

On timelines: 6 to 10 weeks to put the MVP live, 3 to 6 months before reaching a reasonable product-market fit. After delivery, I offer a maintenance package of 100 to 300 € per month to support scaling, fix bugs, add priority features, and keep the infrastructure healthy as growth unfolds.

If you have a SaaS idea and want to discuss it without commitment, the contact page is the fastest way to reach me. You can also browse the portfolio to see web projects delivered in 2026 and judge the level of finish you can expect. The first conversation is free, whether or not it leads to a collaboration.