Free tool
Roast My Idea
Paste your idea. Get a brutally honest roast you can actually share.
Most idea feedback is too polite to be useful. This roasts your idea honestly: a real score, one sharp line on what's actually wrong (or right), the assumption most likely to kill it, and the sharper version that could work. Free, no signup, and shareable.
No idea handy? , or .
Someone roasted “an app like Uber but for dog walking.”Here’s what came back:
Don't build it
“It's Uber for dog walking, which is to say it's Rover, which already exists and already owns every dog owner you'd ever reach.”
Dog owners who'll happily use whichever app their neighbour already uses, so switching costs work against you, not for you.
A two-sided marketplace with no wedge against entrenched incumbents who already have both sides locked in.
Pick one city and one breed-specific or high-end niche Rover underserves, win it completely, and let word of mouth do the cold-start.
A roast only helps if it's true. This isn't snark for its own sake. It's the honest read a good founder friend would give you, dialled up: the line you'd screenshot because it's fair, not because it's mean.
You get a conviction score out of 10, the buyer who actually pays (or the fact that nobody clearly does, which is usually the real problem), the fatal flaw, and a redemption: the one wedge or niche where this idea could genuinely work.
It's a fast gut-check built to share. The full Kasspian report goes deeper, with market sizing from real sources, the full risk map, a two-week test plan, and a verdict backed by citations.
Got your number? Now get the customers.
Kasspian maps the two or three channels your buyers actually live in, the ones to skip so you stop spreading thin, and the one move to run this week — grounded in how real founders got their first customers. Honest read on the idea included.
Find my first customersTeardowns & founder moves
One week, a dead startup and why it died. The next, a play to get your next customers.
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Common questions
How do you roast a startup idea?
Describe it in a sentence and get an honest verdict: a score out of 10, one sharp line on the real problem or strength, who actually pays, the fatal flaw, and the version that could work. The roast is honest first and funny second, never just mean.
Is my business idea bad?
Most raw ideas aren't bad so much as unproven, but some genuinely shouldn't be built because no specific buyer will pay. This tool scores that honestly and names the assumption most likely to kill it, so you find out cheaply.
Is the roast tool free?
Yes, free with no signup. You get the score, the roast, and the fatal flaw instantly, plus a shareable card. The full Kasspian report goes deeper with sourced market sizing and a two-week test plan.