How to Validate a SaaS Idea With Real Customer Interviews

Most founders learn how to validate a SaaS idea through interviews the hard way: they ask leading questions, get polite agreement, build the thing, and then wonder why nobody buys. A validation interview is only useful if it's structured to surface the truth, not to confirm what you already believe.

Ask about the past, not the future

"Would you use a tool that does X?" is the single most misleading question in startup validation — almost everyone says yes to be polite. Instead, ask what they did the last time this problem came up. Past behavior is evidence. Hypothetical future behavior is a guess dressed up as a data point.

• "Walk me through the last time this happened." Forces a concrete story instead of a hypothetical opinion.
• "What did you try to fix it?" Reveals whether they've already spent money or time solving it — the strongest signal there is.
• "What are you using today?" If the honest answer is "a spreadsheet and nothing else," that's not always bad — it often means the market hasn't been served well, not that it doesn't exist.

In summary, the key metric for how to validate a SaaS idea through interviews is whether the person describes a specific past workaround, not whether they agree your proposed solution sounds useful — agreement is cheap, a described workaround is not.

Watch for the false positive

The most common false positive in customer interviews is enthusiasm without commitment. Someone can be genuinely excited about your idea and still never become a paying customer, because excitement costs nothing. Before ending an interview, ask for some form of commitment — a specific next step, a follow-up call, an email for the waitlist — and treat a "maybe later" as a soft no.

1. Interview 8–10 people who already have the problem. Fewer than that and you're pattern-matching on noise; more than that with no new information means you've heard enough.
2. Ask every person the same core questions. Consistency lets you compare answers instead of chasing whichever conversation felt most exciting that week.
3. End with a real ask. "Can I send you early access when it's ready?" turns a conversation into a measurable signal — track the yes rate, not just the vibe.

The main takeaway from analyzing indie trends is that a validation interview without a concrete ask at the end is just a friendly conversation — the ask is what turns polite interest into a number you can actually act on.

Your next step

Draft five past-behavior questions, book time with people who've actually complained about the problem publicly, and track how many give you a real next step versus a polite "sounds cool." That ratio is your validation signal.