"Is my app idea good?" is the wrong question. The right question is: does it pass the nine signals that real ideas pass before anyone writes a line of code? Good ideas are recognizable from the outside. Bad ones feel just as exciting from the inside, which is why most founders need an external checklist.
Signal 1: You can name three real people who'd pay tomorrow
Not "small business owners." Not "freelancers." Three humans, by first name, with a problem so painful they'd Venmo you this week. If you can't, your idea is still a category, not a product. See Niche Down or Die.
Signal 2: The problem is "hair on fire," not "nice to have"
Vitamins lose. Painkillers win. If your target user can ignore the problem for another six months without consequences, they will. Read Hair on Fire Problems for the test.
Signal 3: People are already paying for a worse solution
The single best market signal is a competitor with paying customers and 2-star reviews. That tells you the market exists AND that there's room. A market with no incumbents is usually a market with no demand.
Signal 4: You have an unfair distribution path
Can you reach 100 of your target users this week, for free, without ads? If yes, you have distribution. If no, building the product won't fix that. See Distribution-First Thinking.
Signal 5: You've lived the problem yourself
Outsider founders win when they're solving their own previous job's pain. You move faster, write better copy, and pick the right features because you've been the user.
Signal 6: You can describe the wedge in one sentence
"Unlike [competitor], we [thing they don't do] for [specific niche]." If the sentence comes out fuzzy, your positioning is fuzzy and the launch will be too.
Signal 7: The price is obvious within $10
If you can confidently say "this is a $49/month product" without flinching, you understand the value. If you're guessing between $5 and $200, you don't.
Signal 8: You'd still build it if AI didn't exist
AI is a feature, not a business. If "we use AI" is your moat, the next model release is your obituary.
Signal 9: You can do a 48-hour fake-door test today
Ideas that pass all eight signals above survive a real demand test. See 7 Cheap 48-Hour Experiments.
Hit 7+ of 9 and you have a green light. Hit fewer than 5 and the honest move is to keep looking. The cost of being wrong here is six months of your life.