Customer Interview Questions That Reveal Real Demand
Good customer interview questions ask about the past, not the future: the last time the problem happened, what the person did, what it cost and what they have already tried. Avoid asking whether they would use or buy your idea, because people answer that politely, not honestly.
By Javier Alonso, Founder & CEO. Updated .
Three rules for discovery interviews
- Talk about their life, not your idea. Keep your product out of the conversation until the end, if you mention it at all.
- Ask about specifics in the past. "Tell me about the last time" produces facts. "Would you ever" produces guesses.
- Listen far more than you talk. Aim to speak for less than a fifth of the call. Follow-up questions such as "why was that hard?" and "what happened next?" do most of the work.
The questions
Context
- What does a typical week look like in your role?
- Where does [the problem area] fit into that week?
The last time it happened
- Tell me about the last time you dealt with [the problem].
- What were you trying to get done?
- What made it hard?
- What happened as a result?
Current workarounds
- How do you handle this today?
- What tools, people or spreadsheets are involved?
- What have you tried that did not work? Why did you stop?
Cost and priority
- Roughly how much time or money does this cost you in a month?
- Have you paid for anything to fix it? How much?
- Where does this rank against the other problems on your plate?
Closing
- Who else deals with this problem that I should talk to?
- Can I follow up when I have something to show you?
Questions to avoid
- "Would you use a product that…?" People say yes to be helpful.
- "How much would you pay for…?" Hypothetical prices are unreliable. Ask what they pay today instead.
- "Do you think this is a good idea?" You are asking for a compliment, not information.
- Leading questions such as "Isn't it frustrating when…?" put the answer in their mouth.
Running and recording the interview
Book 20 to 30 minutes and tell the person you are researching a problem, not selling. Take notes in their words, not your summary, because exact phrases become your marketing copy later. Straight after each call, write three lines: the strongest pain you heard, the evidence behind it (a workaround, money spent, time lost) and anything that contradicts your assumptions.
After 5 to 10 interviews, put the notes side by side. Look for problems described unprompted by most people, the same workaround appearing again and again, and existing spend. Those patterns are your validation evidence.
Example
Weak: "Would you use an app that reminds you to send invoices?" (Answer: "Sure, probably.")
Strong: "Tell me about the last invoice that was paid late." (Answer: "A client paid 47 days late in March. I sent four emails and had to delay paying my own contractor.") The second answer tells you the pain, its cost and the current workaround, which is manual chasing by email.
For your role
- Founders
- Interview before you build and again after launch. The questions change but the habit of asking about the past does not.
- Mentors
- Ask to read a founder's raw interview notes, not their summary. Leading questions and missing follow-ups are easy to spot.
- Accelerators & incubators
- A shared interview template across a cohort makes evidence comparable between teams.
Primary sources
- The Mom Test — Rob Fitzpatrick
- Startup School Week 1 Recap: Kevin Hale and Eric Migicovsky — Y Combinator
- Practical Design: User Observation — Y Combinator
Common questions
- What are the best customer interview questions?
- Questions about past behavior: the last time the problem happened, what the person did about it, what it cost and what they have tried. They reveal real demand without leading the answer.
- How many customer interviews should I do?
- Usually 5 to 10 with the same segment before patterns are clear. Stop when answers start repeating, then interview a different segment if you need to compare.
- Should I pitch my idea during a customer interview?
- Not in the main part of the interview. Pitching makes people polite rather than honest. If you show the idea at all, do it in the last few minutes, after you have learned about their problem.
- How do I find people to interview?
- Start where your target customers already gather: professional communities, forums, LinkedIn, events and your own network's introductions. Ask each interviewee who else you should talk to.
Put it into practice
Turn interview notes into a structured validation plan with the evidence in one place.