Customer Interviews for Startups: Questions, Scripts & Best Practices

The Mom Test

Rob Fitzpatrick's "The Mom Test" is the essential framework:

The Mom Test: Talk about their life instead of your idea. Ask about specifics in the past instead of generics or opinions about the future.

Your mom will lie to you (to be supportive). But she can't lie about facts from her past. Focus on what people have done, not what they would do.

Questions That Work

Understanding the Problem

• "Walk me through the last time you dealt with [problem]."
• "What's the hardest part about [activity]?"
• "How are you solving this problem today?"
• "What have you tried that didn't work?"
• "How much time/money does this problem cost you?"

Understanding Urgency

• "When did you last search for a solution to this?"
• "What would happen if this problem never got solved?"
• "Is this in your top 3 priorities right now?"

Understanding Buying

• "What tools do you currently pay for?"
• "Who would need to approve this purchase?"
• "What would make you switch from your current solution?"

Questions to Avoid

Never ask:

• "Would you use this?" (Hypothetical, meaningless)
• "Do you think this is a good idea?" (Asking for validation)
• "Would you pay $X for this?" (They'll say yes to be nice)
• "Don't you hate when [problem]?" (Leading question)

Instead:

• "Have you looked for solutions to this?" (Shows real intent)
• "What happened the last time you tried to solve this?" (Reveals actual behavior)
• "What are you currently paying for similar tools?" (Real spending data)

Finding Interview Subjects

Where to Find Them

• Your network — LinkedIn connections, friends of friends
• Online communities — Reddit, Discord, Slack groups for your target audience
• Twitter/X — People complaining about the problem publicly
• LinkedIn Sales Navigator — Search by job title, company size
• User Interviews — Paid service to recruit participants
• Cold outreach — Email people at target companies

How to Ask

Keep it casual and short:

"Hi [Name], I'm researching how [target audience] handles [problem area]. Would you have 15 minutes to share your experience? I'm not selling anything — just trying to understand the space. Happy to share what I learn."

Offer something in return: share your research findings, a coffee gift card, or just gratitude.

Running the Interview

Before

• Have 5-7 questions prepared (but be ready to go off-script)
• Research the person/company briefly
• Set up recording (with permission)
• Plan for 20-30 minutes

During

• Let them talk 80% of the time
• Follow interesting threads with "tell me more about that"
• Ask "why" multiple times to get to root causes
• Note specific numbers, dates, and examples
• Stay curious, not defensive

After

• Write summary within 1 hour while memory is fresh
• Extract key quotes and insights
• Update your assumptions based on what you learned
• Send a thank-you note

How Many Interviews?

Minimum: 10 interviews before making major decisions

Optimal: 15-20 for clear patterns

Signs you have enough:

• You're hearing the same problems repeatedly
• You can predict answers before they speak
• New interviews reveal no new insights

Signs you need more:

• Every interview surprises you
• You're not seeing patterns
• Different people describe different problems

Extracting Insights

After interviews, synthesize with these questions:

• What problem came up most? (This is likely your opportunity)
• What exact words did they use? (Use this language in marketing)
• What surprised you? (Often the most valuable insight)
• What current solutions exist? (Your competitors)
• What would make them switch? (Your differentiation)