Check a startup idea against 12 deal-breakers
Describe the idea in four short fields and get a verdict — Build it, Test it first or Drop it — with reasons, in under a minute. Free with the 2 signup credits.
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What does a startup idea validator actually check?
A startup idea validator scores the idea you bring it. WhittleOS runs 12 deal-breaker checks where a hard failure on any one ends the idea, computes the score in code from seven rated areas instead of asking a model for a number, and binds the verdict to your time, money and skills. The published sample run shows what it refuses, not just what it approves.
Four differences that decide whether a check is worth running
It can return a no
A validator that scores every idea in the 70s has no decision in it — the number moves, the answer never does.
Every idea goes through 12 deal-breaker checks, and a hard failure on any one of them ends the run. A verdict that cannot be KILL is not a verdict.
The Whittle Score is arithmetic, not an opinion
A language model is asked for a number out of 100, and it returns one that sounds right.
The model rates 7 areas; the Whittle Score is then computed in code from a fixed weighting, so the same ratings always produce the same total and grade. What the model cannot do is hand you a flattering number directly.
The problems come with somewhere to look
Market claims arrive as confident prose with nothing behind them.
The published run pulled 56 documented problems out of 41 sources, and 32 of them carry a link you can open. The rest are labelled as our estimate rather than dressed up as evidence.
The verdict is bound to your situation
The same idea gets the same answer regardless of who is asking.
Your time budget, capital, skills and support tolerance are inputs, so an idea that is workable for a funded team and unworkable for one person after hours does not get one shared answer.
The questions an idea has to survive
Every candidate is put through these, and a hard failure on any one of them ends it — that is what makes the answer a decision rather than a score.
- Is there a real, documented problem behind it?
- Is there a path to money that repeats?
- Is there a repeatable way to reach the buyer?
- Can it charge enough to be worth one person's time?
- Can it run without hand-holding every customer?
- Does it survive if one platform changes its rules?
- Is there a product left if an AI vendor ships this feature?
- Can you, specifically, sell and operate it?
- Can it launch without licences or compliance audits?
- Can it sell without legal review and a sales team?
For where the candidates come from in the first place, rather than how one is judged, see where startup ideas actually come from.
What it did against endings that were already known
We ran 8 companies with documented outcomes through the same gate, as anonymized one-liners describing them at founding, under two founder profiles. 5 of them failed in real life and 3 succeeded.
| Founder profile | Said stop on the 5 flops | Said stop on the 3 successes |
|---|---|---|
| Solo, nights and weekends | 4 | 1 |
| Funded team | 2 | 0 |
The solo-founder lens said stop on 4 of the 5 documented flops — and on 1 of the 3 documented successes. That last figure is the one a vendor deletes, so it is the one to read first.
What this does not support, in our own words
- No accuracy percentage. N = 8, hand-picked for known outcomes, anonymized (a model may still recognize a famous case), and hindsight is imperfect. The only claim is: matched the known outcome on these dated, anonymized cases.
- Our verdict is founder-bound — that's the product, not a bug. The same idea gets a different read for a solo founder vs a funded team, so we show both profiles. A "Drop it" on a venture-scale success under the solo lens means "not for this founder," not "bad idea."
- The funded-team lens is deliberately less kill-biased. It holds capital-heavy or under-specified ideas for evidence rather than killing them, so it catches fewer of the historical flops than the solo lens does. The solo lens is the strong dud-catcher.
- Each deal-breaker check verdict is a 5-sample supermajority vote, so the gate is materially more stable run-to-run than a single sample — but the weighted score is still one pass, so borderline cells can drift a point or two. It's a dated snapshot you can re-run, not a statistic — the cells move between runs.
- Kill My Idea returns a uniform "Drop it" on every idea by design — it's the adversarial "argue why not to build this" mode. Single Idea Check is the comparable, discriminating column shown here.
- We catch the duds; we don't always name their exact cause. An adversarial audit found our cited reason is sometimes adjacent to the real one. We claim catch, not diagnosis.
The full table, every row and the outcome key · Why no accuracy percentage follows from it
The same idea, through a tool built to agree with you
On 2026-06-10 we put our own one-liner through 3 tools in one day, including two of our own modes, and recorded what each returned word for word.
"PROMISING" — "Excellent potential! You’re among the top ideas we’ve seen"
KILL (confidence HIGH)
KILL (short-circuited)
One idea, one day, one run through each. That supports exactly one sentence — these were the outputs — and no claim about how any tool behaves in general, or any rate. The date is here so you can re-run it.
Why the encouraging answer is the default, and how to re-ask for a real one
Read a run before you pay for one
A published single-idea check — The full verdict, the seven rated areas and the computed grade on one real idea.
A published Discovery run — 20 sub-markets, 24 pages read in full, and the problems that survived — with their sources.
Questions
- Is it free?
- Your first checks are. Every new account gets 2 credits and no card is asked for; an idea check and a founder read cost 1 credit each. Searching a market for ideas you have not had yet — a Discovery run — is the one thing that needs a paid pack, from 2 credits.
- How long does a check take?
- Under a minute for an idea you bring. A Discovery run takes 10 to 40 minutes per market and runs in the background; we email you when it is done.
- Is this a startup idea validator?
- It is a decision tool, and the distinction is the point. A validator is built to assess the idea you bring; this is built to end the ones that will not work and to tell you what to do next about the one that might — including sourcing candidates itself when you do not have an idea yet.
- Can it tell me my idea is bad?
- Yes, and that is the intended outcome for most ideas. 12 deal-breaker checks run on every idea, and a hard failure on any one of them ends it. The published sample run is worth reading precisely because of what it refuses.
- How accurate is it?
- There is no honest accuracy number, and anyone quoting one is inventing it. Nobody knows whether an unbuilt idea would have sold, so there is no ground truth to score against. What you can check is the reasoning: open the sample run and see whether the problems it cites are real and whether the verdict follows from them.
- Will I get the same verdict twice?
- Not necessarily. The ratings come from a model sampling at temperature 1, so they move between runs; the scoring arithmetic on top of them is fixed. Treat a borderline score as borderline rather than as a measurement.
- What about business idea validation generally — not software?
- The deal-breaker checks are about economics rather than code: whether a real problem exists, whether money repeats, whether one person can reach the buyer and support them. Those apply to a service or a physical product too. The worked examples on this site are software, so that is what the published runs show.
- Is my idea kept private?
- Your ideas and founder profile are yours. We don't sell them, and we don't publish them. Running an analysis does send your inputs to the providers that do the work — our AI provider, and for a Discovery run the market you named goes into the search queries we issue. Nothing else, and nobody trains on it. See the Privacy page for the full list of who receives what.
Nothing to check yet? The free founder read is the honest place to start: it reads your situation before any idea is scored.
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