# How do you validate a SaaS idea before setting up your company?

Updated : 2026-10-24 · Source : https://legalrapide.fr/en/entreprendre/valider-idee-saas/

A SaaS idea is validated when customers **pay**, not when they say they would like to use it. The method has four steps: write down your assumptions, talk to potential customers, ask for a paid commitment (pre-order or pilot), then decide against criteria set in advance. Interviews, prototypes and waiting lists need no legal structure; as soon as you take a payment or deliver a service, you need a legal framework (micro-entreprise or company).

## 1. Write down your assumptions
- **Who** has the problem, precisely: job, company size, situation.
- **How** they solve it today, and what it costs them (time, money, errors).
- **How much** they would pay, and who signs off on the spend.

## 2. Talk to potential customers
Around fifteen interviews are often enough to see the same answers coming back. Ask about the past, not the future: "the last time this problem came up, what did you do?" rather than "would you use this tool?".

## 3. Ask for a commitment
- A **pre-order** or a **paid pilot** at a reduced price, with a delivery date.
- A page presenting the offer and its price, with a sign-up or demo request.
- Taking payment before the company exists: possible in some frameworks, see [can you invoice before receiving your Kbis?](/en/reponses/facturer-avant-kbis/) and the choice between [micro-entreprise or company](/en/entreprendre/micro-entreprise-ou-societe-saas/).

## 4. Decide against criteria set in advance
Before the interviews, write down what will make you launch: for example a number of customers ready to pay, an accepted price, a positive margin per customer in the [margin calculator](/en/entreprendre/calculateur-marge-saas/). If the threshold is not reached, change your target or your offer before writing any code.

## Once the project is validated
Work out the [launch budget](/en/entreprendre/budget-lancement/), then choose the legal framework: [micro-entreprise or company](/en/entreprendre/micro-entreprise-ou-societe-saas/), [SASU or EURL](/en/guides/sasu-ou-eurl/).

## Sources
- [Bpifrance Création: validating your market before launching your business](https://bpifrance-creation.fr/encyclopedie/letude-marche/valider-son-marche/valider-son-marche-lancer-son-acti)