Validate before you build

Find out whether people will commit time or money before you write the product. Conversations, a one-page test and pre-sales cost days, not months.

Also called customer interview rules

What: A set of rules from Rob Fitzpatrick's book: talk about the other person's life and past behaviour, ask for specifics, and avoid pitching your idea or asking whether they would use it.
Why: People are polite about ideas. Questions about what they actually did last time give answers they cannot fake.
Example: Ask "When did you last chase a late payment and what did you do?" instead of "Would you use an app that chases payments?"

Watch out

Counting compliments such as "great idea, I would totally use that" as validation.

Also called customer discovery call

What: A short conversation, often 15 to 30 minutes, with someone in your target group to learn how they experience the problem, what they have tried and what it costs them.
Why: Ten to fifteen interviews usually reveal whether the pain is real, which words people use and who holds the budget.

Watch out

Interviewing only friends and classmates who are not in the target group.

Also called landing page test, fake door test

What: A simple page that describes the product as if it exists and asks visitors to act, such as joining a waitlist or pre-ordering, to measure interest before building.
Why: It tests whether your message makes strangers act, which interviews alone cannot show.

Watch out

Driving only friends to the page, or pretending a product exists and taking money you cannot deliver on.

What: A list of people who left their email to hear when the product launches.
Why: It gives you people to interview and a first audience for launch day. It is a weak demand signal, because an email costs nothing.

Watch out

Treating 500 sign-ups as proof of demand when almost none of them would pay.

Also called pre-order, founding customer offer

What: Taking payment, or a firm commitment, before the product is finished, usually at a discount, with a clear delivery date and a refund promise.
Why: Money is the strongest validation signal. Even three pre-sales tell you more than three hundred sign-ups.

Watch out

Taking pre-orders without a refund policy or a realistic delivery date, which damages trust and may break consumer law.

Also called kill criteria

What: The result you decide in advance that counts as a pass, such as "5 pre-sales from 200 visitors in two weeks", along with what you will do if you miss it.
Why: Deciding before the test stops you from rationalising weak results after you have fallen in love with the idea.

What: Studying the top apps for your problem in the App Store and Google Play: their rankings, prices, paywalls, update history and especially their recent one- and two-star reviews.
Why: Reviews name the missing features and frustrations that a new app could fix, and ranking lists show whether people pay in that category.

Watch out

Entering a category dominated by free apps from large companies without a clear reason people would pay you.

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