How do I define an ideal customer for a product no one is searching for yet?
When there's no existing search demand, you can't define your ICP by category, so define it by the underlying pain and the moment it becomes urgent for someone. Find the people who have hacked together an ugly workaround (spreadsheets, WhatsApp groups, a manual process): that workaround is proof they feel the problem enough to act. Your first ICP is the narrowest group already spending time or money to solve this badly. Expect to be wrong at first and let the people who say yes redraw the boundary for you.
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3 resources, 3 link-checked.
✍️ Essay
✓ Link checkedFreeBeginner
The definitive essay on where good ideas come from: notice problems you personally have, don't force it. Use it as the lens for judging whether your idea is a real problem or a solution in search of one.
This is the book that named customer development and, indirectly, launched the Lean Startup movement. Its examples lean heavily enterprise (procurement cycles, multiple decision makers, solution selling), which makes it the strongest single read for someone validating a B2B idea rather than a consumer app. Treat it as the foundational playbook: dense and dated in places, but the discovery-then-validation spine still holds up.
Vohra shows a repeatable method for narrowing to the customers who most want a product that had weak initial pull. He surveys users, isolates the ones who would be "very disappointed" without the product, and builds a profile of that segment, then doubles down on them. It is one of the clearest walk-throughs of turning fuzzy early signal into a specific customer definition.
Ask users how they would feel if they could no longer use the product, and treat the "very disappointed" group as the seed of your ideal customer.
Build a profile from that high-intent segment first, then decide what to strengthen and which objections to remove.
A caution worth holding: your highest-expectation early users and your eventual broad ICP are not always the same, so revisit the definition as you grow.
