Mom Test customer interview questions for UK indie hackers (2026)

The smoke-test page told you something: there is a signal. Three founding-member clicks, six high-intent Tally submissions, fifty visitors who dwelt past the headline. That is not yet a green light to build - it is a green light to talk.

Now you need to know whether the people who clicked will actually pay. That is what the Mom Test is for: ten short calls, run cheaply, structured against a discipline that stops you from collecting polite encouragement and starts producing the only kind of signal that matters - specific stories of specific people who have spent specific money on a specific workaround they hate.

This post is the UK indie hacker version: the ten questions to ask, the GBP price-anchor question that earns its keep, the four places to find candidates without paying for them, and the three signals that tell you the demand is real enough to fire the Stripe pre-sale link.

Why most founder interviews fail

The default founder interview script reads like this: "Hi, thanks for chatting. Let me tell you about my idea - it does X for people like you. What do you think? Would you use it?"

Every line is wrong. The introduction primes the interviewee to give compliments because they like you. The description fills the conversation with your assumptions, which they will not contradict out of politeness. And the closing question is hypothetical - "would you use it" asks them to predict their own future behaviour, which humans are spectacularly bad at.

The result is a transcript full of "yes, that sounds interesting" and "I would definitely use that" and "great idea". You walk away convinced. You build the product. Nobody pays. You spend three months wondering why everyone lied to you - except they did not lie, you asked questions that could only be answered politely.

Rob Fitzpatrick named the discipline that fixes this the Mom Test in his 2013 book. The premise is sharp: even your mum, the person most likely to want to support you, cannot answer your validation questions honestly if you ask them badly. The fix is to ask questions so well grounded in past behaviour that even a biased respondent cannot accidentally lie.

The three Mom Test rules

The whole framework comes down to three rules:

Rule 1: Talk about their life, not your idea

In the interview, your idea barely comes up. Their life is the topic. What they do all day, what they struggle with, how they handle it now, what they have tried in the past, what worked, what did not, what it cost them. Their life is concrete and answerable; your idea is hypothetical and corruptible.

Rule 2: Ask about specifics in the past, not opinions about the future

Past behaviour is data. Future opinions are guesses. "Walk me through the last time X happened" is a question they can only answer with facts. "Would you use something that did X" is a question they can only answer with a hopeful guess.

Every Mom Test question is built around this distinction. Look at your draft script and circle every verb. If the verbs trend toward the past tense (did, spent, tried, paid, chose, gave up) you are on the right side. If the verbs trend toward the conditional (would, might, could, should) you are still pitching.

Rule 3: Talk less, listen more

A useful ratio is the customer speaking for at least 80 per cent of the call. Your job is to ask the next question and shut up. Long silences are not awkward, they are productive - the interviewee is searching their memory for the specific detail you asked about. Wait it out. Most founders cannot bear silence and fill it with a leading question that contaminates the answer. The discipline of waiting is half the framework.

Ten Mom Test questions for a UK indie hacker

A working script, ordered so each question builds on the last. Use this as scaffolding, not a recital - the best calls follow the interviewee's thread and come back to the script when it stalls.

1. "What does a typical week look like for you in [their role]?"

Wide-open warm-up. Tells you their actual day-to-day, surfaces tools they use, names of people they work with, the rhythm of their week. Almost nothing about your product yet - and that is the point.

2. "What is the most frustrating part of [their domain] right now?"

Open-ended pain hunt. Whatever they name in the first 30 seconds is the live wound. Note it precisely, in their words - their vocabulary is the headline of your future landing page.

3. "Walk me through the last time that happened."

The single highest-leverage question in the whole framework. Specific recent moment, told in their own words, with every detail you need to read demand: trigger, response, time taken, money spent, people involved, emotional weight.

4. "How are you dealing with it now?"

The workaround question. This is where you get the GBP price anchor for free. If they are paying GBP 100 a month for a duct-tape stack of three tools that almost works, you know which price band you are playing in. If they are doing nothing, your job got harder - "nothing" is a sign that the pain is below the threshold of motivated action.

5. "How much would you say that costs you - in time or in pounds?"

The explicit price-anchor question. The phrasing matters: "in time or in pounds" gives them permission to answer in either currency, and the conversion is yours to do afterwards. A solo founder saying "it eats half a Friday every fortnight" at a billing rate of GBP 80 an hour is telling you the workaround costs them GBP 200 a month - the price ceiling you can charge against.

6. "Have you ever paid for a tool to fix this?"

The track-record question. Past spend is the strongest predictor of future spend. Someone who has paid for two failed attempts is far easier to convert than someone who has never paid for anything in this category - they have already crossed the willingness-to-pay threshold once, and they are looking for the right answer rather than questioning whether to spend at all.

7. "What did you try first - and why did you stop using it?"

Competitor intelligence and switching pain. The reason they abandoned the previous tool is the wedge you sell against. "It got too expensive" tells you to price below. "It was too complex" tells you to simplify. "It did not handle the UK rules" tells you to specialise.

8. "If a tool fixed this properly, what would 'properly' look like?"

The forward-looking question. Note the trick - it is framed as "if a tool fixed this", not "if my tool fixed this". You are mining their definition of success without revealing yours, so their answer is not anchored to your features.

9. "Who else has this problem - can you introduce me to two of them?"

The referral test. This is a Mom Test signal multiplier. If they cannot name two people with the same pain, the audience may be smaller than it looked. If they offer the intros without prompting, you have a champion. If they hedge, you have a curious bystander.

10. "If I built a working version, what would make you the first to pay?"

The commitment question. Not "would you use it" - you cannot use a future-conditional answer. The phrasing forces specifics: a price, a feature, a guarantee, a trial period, a refund promise. Note the specifics in their words; the answer becomes the founding-member offer page.

The price-band question - the one you must not skip

Question 5 is the load-bearing question of the whole script. Founders skip it because it feels confrontational - asking about money makes a friendly chat feel transactional. Push through the discomfort. Every other answer in the interview is contextual; the price band is the only one that maps directly to revenue.

A useful follow-up: "and how do you decide whether something is worth paying for?" The answer tells you the buying process - whether they expense it from a company budget, whether their accountant signs off, whether they pay personally and reclaim, whether they need approval. UK SMEs in particular have specific buying rhythms (most spend below GBP 100 a month gets nodded through, anything above usually needs a second signature) and you want to know which side of that line your price sits on.

If they cannot name a number, that is data too. It usually means the pain is real but the perceived value is fuzzy - which tells you the landing page work is on the GBP outcome statement, not on the feature list.

Where to find ten UK candidates in a week, without paying for them

Paying for interviews skews the signal: people will tell you what they think you want to hear in exchange for the gift card. Free sourcing is harder but cleaner. Four lanes that earn their keep:

LinkedIn UK boolean search + cold DM

Search LinkedIn with the audience role + UK filter. Pick people whose profiles suggest the problem (job title, company size, recent post topics). Send a short DM:

"Hi [name] - I am building research-stage tooling for [audience]. Not selling anything. Would you give me 15 minutes to walk me through how you currently handle [problem]? Genuinely useful to me, and I will share the patterns from the calls with everyone I interview if helpful."

Conversion rate is around 10 per cent if your audience is well-defined. Twenty DMs gets you two calls; sixty DMs gets you six. Spread across a week.

Niche UK subreddits

Reddit will auto-remove self-promo, so the play is to comment usefully on three threads where the problem comes up, then DM the people who upvote you with the same script as above. UK-specific subs that tend to convert: r/SmallBusinessUK, r/UKPersonalFinance, r/SideHustleUK, r/AskUK, and sector-specific subs (r/CharteredAccountantsUK, r/UKEtsy, r/UKfreelance).

The discipline: comment first, DM second, never post promotional content on the subreddit itself.

Founder WhatsApp and Slack groups

The IndieHackers Slack, regional founder broadcasts (London, Bristol, Manchester), sector-specific Slack groups (UK SaaS founders, UK e-commerce founders). Ask for permission to share once, then post a single short message:

"Building research-stage tooling for [audience]. Looking for 15-minute calls with anyone who fits. Not selling - genuinely just need to learn how you currently handle [problem]. DM if open to a slot this week."

UK founder groups respond well to honest framing. Avoid the "quick favour" framing - it lands as transactional.

IndieHackers London + in-person meetups

The slowest channel and the highest-quality signal. Three or four interviews from in-person events tend to be worth ten from cold DMs - tone, body language, and the willingness to give long answers all change in person. London has weekly IndieHackers meet-ups, monthly Tech for Good UK events, and sector-specific founder dinners; book one a week while you are running the cycle.

The interview logistics - 15 minutes, three rules

Calls are 15 minutes. Not 30. Short calls force focus and force you to send the follow-up rather than burning the whole conversation in one go. Use Calendly with a 15-minute slot and a 5-minute buffer.

Three rules that change everything:

• Record with consent. Ask at the top: "I'd love to record this so I can listen back rather than scribble notes - okay with you?" Almost everyone says yes, transcription is free with Otter or Granola or the built-in option in your call tool, and you will pick up details you missed live.
• Ask the open question first. Always start with "what does a typical week look like" - it gets them talking before you steer. Steering early kills the signal.
• Send the follow-up within the hour. A short email, three lines, with one specific thing you heard and one specific question you want to ask later. The follow-up locks in goodwill and sets up the introduction request (question 9) if you did not get it on the call.

The three signals that green-light the pre-sale

After ten calls, three signals tell you the demand is real enough to fire the Stripe link. You need all three, from at least three independent interviewees.

Signal 1: Specific painful trigger in the past 30 days

Not "I struggle with this in general" - "last Tuesday morning this exact thing happened and it cost me half a day." Specificity in recent time is the strongest predictor of urgency. Diffuse historical pain almost never converts to a paid sign-up.

Signal 2: Current workaround with measurable GBP cost

They are spending money or time today on an inferior fix - tools, contractors, lost revenue, billable hours, late fees, missed opportunities. A measurable current cost in pounds gives you both the willingness-to-pay (already established) and the price ceiling (anything materially below their current spend wins).

Signal 3: Decision-maker access

They personally hold the budget for this problem, or they can name and route to the person who does in fewer than two emails. If neither is true, even strong pain rarely converts - the buying friction is the killer.

Three signals, three independent interviewees, all three boxes ticked. That is the green light. Open the Stripe payment link, send the founding-member email to the six strongest candidates from your Tally submissions and your ten calls, and hold yourself to the three-sale rule.

If you hear all three signals from fewer than three people after ten calls, run another five. If you hear them from no one, the audience or the framing is wrong - re-read your notes, find the recurring objection, and re-shape the offer before re-running interviews. If you still hear nothing after fifteen calls, this is a clean kill - the validation has done its job, and the cost was a week of evenings rather than six lost weekends.

The interview kit fits inside the broader validation sequence

The Mom Test calls are the middle artefact in the three-step UK micro-SaaS validation kit:

1. The smoke-test page - read the demand signal in one week from 100 targeted visitors
2. The Mom Test interviews (this post) - find out which signal-givers will actually pay, with the three signals as your decision gate
3. The Stripe pre-sale link - convert the strongest signals into the first three founding-member sales

Each step costs almost nothing. Each step filters faster than the next would. Each step is reversible. The whole sequence is calibrated to spare you from the only failure mode an indie hacker cannot afford - six lost weekends spent building the wrong product because you mistook polite encouragement for demand.

The discipline of the Mom Test is uncomfortable. Asking about money makes a friendly chat feel transactional. Pushing for specifics makes you feel like a lawyer. Sitting through silences makes you want to fill them. All of that discomfort is the point - the framework works because it forces you to extract signal that easy chats hide.

Ten calls. One script. Three signals.

Block out two evenings this week, book ten Calendly slots, and run the script. By Sunday you either have a green light for the pre-sale or a clean kill on the idea - and either outcome is worth more than the week it took to find out.

The bonus: every interviewee who hears your honest curiosity about their problem (without a pitch) becomes a warm contact for life. Even the calls that kill the idea leave you with two or three people who will pick up the phone for the next one.

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Want the data behind the UK problems that are actually worth interviewing into? IdeaStack publishes weekly data-backed reports on UK business opportunities - search volumes, competitor pricing, SERP gaps, and Mom-Test-shaped builder prompts. Browse the latest free reports.