How to find app ideas people will pay for: mine negative App Store reviews
A five-step method to turn 1–3★ App Store reviews into ranked app ideas, with real numbers from 17,581 reviews across habit, budget and fitness apps.
The best app ideas are not invented in a brainstorm. They are already written down, thousands of times, in the 1–3★ reviews of apps people pay for. Every review that says "I'd pay for this if it didn't…" is a user describing the product they want and can't find.
This guide explains the method we use at Grumpi, step by step, with the numbers from our first three studies: 17,581 App Store reviews collected, 8,693 negative reviews read, 9,667 complaints counted.
In short:
- Start from a niche where people already pay, not from an idea.
- Pick competitor apps with lots of ratings and a rating that isn't perfect. On the App Store, "not perfect" means under 4.7: the median rating is 4.73.
- Read only the 1–3★ reviews, group the complaints, and count them.
- A complaint that comes back hundreds of times, across several apps, is a product. A complaint that comes back five times is an anecdote.
Why negative reviews beat brainstorming
An idea from a brainstorm has no evidence. A complaint repeated in 300 reviews has three things a brainstorm can't give you:
- Proof of demand. The user downloaded an app in your niche, often paid for it, and cared enough to write.
- The exact problem, in the user's words. "I cancelled it. Yet I continue to get charged." is more useful than any persona.
- A switching argument. You know what the competitor gets wrong, so you know what your landing page should say.
Positive reviews tell you what works. Negative reviews tell you where the market is underserved.
Step 1: pick a niche where people already pay
Look for categories where users pay for a subscription or a one-time purchase: habit trackers, budgeting, fitness, sleep, language learning, note taking. If nobody pays in a niche, complaints won't turn into revenue.
Then list the main search terms of the niche ("habit tracker", "budget app", "home workout") and note the apps that show up.
Step 2: choose competitors in the "sweet spot"
You want apps with many users and real dissatisfaction. Two filters:
- At least 5,000 ratings. Below that, the App Store gives too few recent reviews to analyze: some apps return fewer than 50.
- An average rating between 3.0 and 4.7.
Why 4.7 and not 4.0? Because App Store ratings are inflated: apps ask for a rating right after a good moment. We looked at 655 apps with at least 1,000 ratings, across 20 niches:
| Average rating | Share of apps |
|---|---|
| Under 4.0 | 1% |
| 4.0 to 4.5 | 9% |
| 4.5 to 4.7 | 28% |
| 4.7 to 4.8 | 31% |
| 4.8 and above | 31% |
The median is 4.73. If you only look at apps under 4.5, you keep one app in ten, and often a single app per niche.
A 4.7 rating doesn't mean happy users either. The written reviews skew negative: on apps rated 4.5 to 4.7, we found that 24% to 70% of recent written reviews were 1 to 3 stars. Above 4.8, the share drops fast.
Step 3: collect the 1–3★ reviews
Take the most recent reviews of each app, in several English-speaking countries if you can (the US, the UK, Canada, Australia). The App Store's public feed returns around 500 recent reviews per app and per country, which is enough.
Keep only the 1, 2 and 3-star reviews. A 3-star review is often the most useful: the user likes the idea of the app and explains precisely what stops them.
Step 4: group the complaints and count them
Read each review and write down every distinct complaint it contains. One review can hold several: "too expensive, and it crashes on my iPad" is two complaints. Then merge the complaints that describe the same problem and count them.
We sort them into five families:
| Family | Example |
|---|---|
| Pricing | Charged after cancelling, paywall before trying the app |
| Usability | Cluttered screens, too many steps to log something |
| Missing feature | No CSV export, no way to swap an exercise |
| Bloated app | Users want one feature, not the whole suite |
| Bug | Crashes, sync failures |
Set bugs aside when you look for ideas: a crash is the developer's problem to fix, not a product opportunity. Keep counting them, though. They tell you how much users are ready to forgive.
Step 5: turn frequent complaints into ideas, and rank them
A complaint becomes an idea when you can describe the product that removes it. Score each idea on three questions:
- How often does the complaint come back? Hundreds of mentions beat dozens.
- How crowded is the answer? If ten apps already fix it, the complaint is old news.
- Is the switching argument clear? "One price, no subscription traps" fits on an App Store screenshot. "Better UX" doesn't.
At Grumpi, the ranking is the score (out of 10) weighted by the number of mentions, so a solid idea backed by 1,000 complaints comes before a brilliant idea backed by three.
What the method found in three niches
| Niche | Reviews collected | Negative reviews read | First family of complaints |
|---|---|---|---|
| Habit trackers | 5,448 | 3,537 | Pricing, 50% |
| Budget apps | 4,972 | 2,524 | Bugs, 56% |
| Fitness apps | 7,161 | 2,632 | Pricing, 59% |
The same pattern shows up in all three: users don't leave because the core feature is bad. They leave because of how they are charged. Paywalls before the first use, weekly prices higher than a gym, charges after cancelling. A competitor that is simply honest about pricing has a ready-made pitch.
The limits of the method
- Reviews over-represent angry users. That's the point, but it means the volume of complaints is not the volume of users.
- Recent reviews only. You see today's problems, not those fixed two years ago, which is what you want for a new product.
- English-speaking markets. A complaint that is everywhere in the US may not exist in Germany.
- Demand is not willingness to pay. Some complaints come from users who want everything free. Count them, but don't build a business on them.
FAQ
How many reviews do I need to find a good app idea?
Aim for at least 1,000 negative reviews across four to six competing apps. Below a few hundred, a single angry thread can look like a trend.
Should I only target apps with bad ratings?
No. On the App Store, the median rating is 4.73, so apps under 4.0 are rare. Target apps between 3.0 and 4.7 with at least 5,000 ratings: they have the users and the complaints.
Are 3-star reviews worth reading?
Yes. They often come from users who like the app and explain exactly what is missing. They are among the most precise sources of feature ideas.
Can I do this without code?
Yes, by hand, with a spreadsheet: copy the reviews, tag each complaint, and count. It takes days per niche. Grumpi automates the collection, the reading and the ranking, and delivers the result as a report.