The Developer's Money Handbook
Getting Started · Chapter 3

Validating demand: before you write code

This is the step developers love to skip — and the one that kills the most projects. Writing code is what we're best at and enjoy most, so the second we have an idea we put our heads down and start building. Three months later we ship — and nobody shows up. The entire point of validation is to prove, at the lowest possible cost and before you sink in serious time, that real people will actually pay.

!
The number-one killer: no market need CB Insights' classic analysis of why startups fail shows that "no market need" has long topped the list, accounting for roughly 35–42% of failed startups — more common than running out of cash or team problems. In other words: what usually kills a project isn't that you failed to build the thing, it's that you built a thing nobody wanted.Source: CB Insights "Top Reasons Startups Fail," widely cited in validation literature (see Sources)

Two kinds of validation — don't conflate them

  • Problem validation: Is this pain point real, and painful enough? How are people muddling through it right now?
  • Solution validation: For my specific solution, will they use it — and will they pay for it?

The order is problem first, solution second. A common mistake is to skip problem validation and jump straight to validating the solution — and end up with a more polished version of a problem nobody actually feels.

The validation toolbox (cheapest to most expensive)

  1. Customer interviews (the cheapest and most underrated) Find 5–10 people in your target audience and ask how they handle the problem today. The key: ask about real past behavior, not assumptions about the future. Don't ask "Would you use a product like this?" (everyone politely says "yes") — ask "When was the last time you ran into this problem? How did you solve it? How much money or time did it cost you?" This is the approach The Mom Test boils down to: ask the kind of concrete questions "even your mom can't fudge with a white lie."
  2. Landing page test Build a landing page for a product that doesn't exist yet: spell out what it solves, who it's for, and roughly what it costs, then add a "Get it now / Join the waitlist" button. Push it to your target audience (communities, ads, X) and watch the conversion rate. This is where the developer's edge kicks in — you can ship it in one evening; everyone else waits a week.
  3. Fake door test Put a "Buy / Subscribe" button on the landing page; when clicked, it shows "Coming soon — leave your email and we'll let you know first." The click-through rate quantifies real purchase intent — far more honest than "likes."
  4. Waitlist / pre-registration Collect emails — this both validates interest and builds your first batch of users. Note: leaving an email is a very low bar, so email counts will overstate real demand. Don't get fooled by vanity numbers.
  5. Pre-sales / deposits (the strongest signal) Get people to put down real money before the product even exists (a full purchase, a deposit, or an early-bird buy). Willingness to pay is the only demand signal that never lies. If you can pre-sell it, you've basically validated.
Ranking signals by how much they're worth Saying "I'd buy it" < leaving an email < clicking a fake-door buy button < joining a paid waitlist < actually paying. The further right, the more credible. When you validate, lean as far right as you can — don't treat "lots of upvotes" as success.

A lightweight, developer-friendly validation flow

String the tools above into one sequence and you can usually run it in a few days to two weeks:

StepActionSignal to read
1. DefineWrite down "I solve [what] for [whom]" plus a hypothetical customer profileCan you say it in one sentence?
2. Find peopleList 3 channels that reach your target audience (a subreddit, a community, a keyword)If you can't reach them, go back and switch niche
3. InterviewTalk to 5–10 real users; ask about past behavior and spendDoes the same strong pain point keep coming up?
4. Landing pageShip a page with a clear value prop + price + CTAVisitor → signup/buy-click conversion rate
5. Ask for moneyTry a pre-sale, early-bird, or depositDoes anyone actually pay?

When to stop validating and start building

Validation isn't infinite procrastination. Once you get a clear "people will pay" signal (a successful pre-sale, or several interviewees spontaneously asking "Can I buy it now? When does it launch?"), stop researching and start building the minimum viable product (MVP). Perfect validation doesn't exist; the goal is to bring risk down to an acceptable level, not to eliminate it.

!
Validation ≠ asking your friends Friends and family will say "it's great, I'd use it" to spare your feelings. That's a false signal. You have to find strangers in your target audience who owe you no politeness, and test them with costly actions like "will you pay / will you give me your email" rather than zero-cost lip service like "do you like it."

What to remember from this chapter

  • "Nobody wanted it" is the number-one cause of startup death (CB Insights, ~35–42%); validation exists to prevent it.
  • Validate the problem first, then the solution; ask about real past behavior, not future assumptions.
  • The toolbox: interviews → landing page → fake door → waitlist → pre-sales, increasing in both cost and credibility.
  • The hardest signal is "someone actually pays" — once you have it, stop researching and start building the MVP.

Validation's done and the product's underway. Next we move into the advanced part: first we'll fill in a few genuinely useful marketing frameworks — they'll become the underlying mental model behind every customer-acquisition move you make later.