How to validate an iOS app idea with App Store data before you write code

Every indie iOS developer has a notes file full of app ideas. The hard part is not having ideas, it's knowing which one deserves the next three months. Surveys, landing pages and "would you pay for this?" posts are slow and noisy. The App Store already publishes better evidence every day, if you know where to look.

#Start from what already works

The usual approach is to start from a search keyword and ask "is there room for me?". That tells you about demand, but not whether a newcomer can win it. Plenty of searches are popular and completely locked by apps that launched in 2012.

So turn it around. Start from apps that are young and already earn:

• Earn means the app ranks on Apple's Top Grossing chart, overall or in its category. Top Grossing ranks apps by revenue, so a rank is a public, daily revenue signal.
• Young means the app launched recently. We use under 24 months for the US store and under 12 months for smaller stores, where charts are easier to enter.
• Then leave out big tech (Google, Meta, TikTok and the like). Venture-funded platforms are caught one step later, when you ask whether a concept is buildable at all.

What is left is a list of apps that a small team launched recently and that customers already pay for. Each of them is a small proof that the door is open.

#Group apps into concepts

A single app is an anecdote. The useful unit is the concept: the job the app does for its user, narrow enough that apps in it compete for the same searches. "Budget meal planner" is a concept. "Food" is not.

Group the young earners by concept and ask four questions. Each one gets a score from 0 to 100:

The weights are our current rules of thumb, not laws. What matters is that each part is explicit. When an idea scores 72, you can see that it's 72 because three developers launched in the last six months, not because a black box said so.

#Why repeat matters most to a solo developer

A single young earner could be a founder with a big audience, a lucky TikTok, or a paid acquisition machine. Two or three unrelated developers earning with the same concept is much stronger: it means the demand is in the market, not in one company's marketing. It also tells you that the concept is learnable. You can study three apps, read their reviews and see what they all get wrong.

#Why pull is measured in ratings, not revenue

An app can reach the Top Grossing chart with paid installs and an aggressive paywall. That proves people can be sold the app, but it doesn't prove they look for it, and you would need the same ad budget to compete. Ratings are a rough proxy for real, engaged users. We flag an app as likely paid traffic when its estimated revenue is above about $150,000 a month while it has fewer than 150 ratings in total.

#Adjust for what you can actually build

A perfect score is worthless if you can't ship it. Multiply the score by a buildability factor:

• Solo (×1.0): one developer can ship a good first version in weeks.
• Hard (×0.6): possible, but needs data deals, a moderated server, or heavy per-use AI costs.
• No (×0): needs content rights or licences (live sports, TV, music), the company's own hardware or service (a remote for one TV brand, a companion app for a smart device), or it is simply a funded company's product.

Then apply penalties when the evidence is weak:

• Mostly paid traffic (more than 60% of the concept's revenue comes from likely paid-traffic apps): ×0.8.
• Revenue estimated from small category charts only, where the mapping from rank to revenue is a guess: ×0.85.
• The concept earns through paid installs by design (ad-driven utility clones, for example): ×0.75.

#The traps that look like great ideas

These are the patterns that most often produce a high-scoring idea that a solo developer should still skip:

• Brand and navigational searches. "fox news", "samsung tv remote" and "mercedes me" are popular searches, but people are looking for one specific app. Ranking second is worthless. A good filter: if the top result's name is essentially the search term, it is a brand search.
• Licensed content. Live football, movie streaming and music catalogs score well on demand and revenue. You can't license the content.
• Hardware and service companions. An app for one brand's car, smart mug or TV depends on that company's API, and the company usually ships its own app.
• Winner-take-all markets. If the top two apps hold most of the market's ratings, the newcomers you see are probably fighting over scraps. We check what share of the concept's ratings the top two apps hold.
• Visibility without traction. A young app that shows up in search but gets few new ratings a month isn't proof of anything. Look at ratings per month, not just rank.

#Write the verdict down

After scoring, sort ideas into three groups:

• Build (score 55 or more, and solo-buildable): proven, repeatable, still open. Worth a week of deeper research and a prototype.
• Consider (35 to 54): something is missing, often repeat or pull. Worth watching; a second young earner can flip it.
• Skip (below 35, or not buildable).

For a Build idea, the next week of research is concrete:

1. Install the young earners. Note their onboarding, paywall and price.
2. Read their 1- and 2-star reviews. The most common complaint is your positioning.
3. Check the searches they rank for, and which of those have weak top-10 results.
4. Define the smallest version that fixes the top complaint, and ship it.

#How Fledly does this

Fledly runs this method every day on the US Top Grossing charts (and the UK, Canada, Australia, Germany and Finland for repeat evidence). It classifies each young earner into a concept, scores the concept with the parts above, and shows every part with its reason in an idea card, together with the competitors' prices and their users' top complaints. Revenue figures are estimates from chart rank and are labelled as such.

For a full run of this method on real data, see 357 young iPhone apps already earn on the US Top Grossing charts.

You can apply the same method by hand with a spreadsheet and the public charts. It takes a few hours per category. Fledly exists because we wanted it every morning for all of them.

#Frequently asked questions

#What is the best way to validate an iOS app idea?

Look for apps under one to two years old that already rank on the App Store's Top Grossing chart for the same concept. If two or three unrelated developers make money with it and their apps gain real ratings every month, the idea is proven and the market is still open to newcomers.

#How do I know if an app idea is too competitive?

Check the age and ratings of the apps that earn. If every earning app is many years old and the top two hold most of the ratings, newcomers rarely break in. If several apps launched within the last year and already earn, there is room.

#How can I estimate how much an app makes?

Top Grossing rank is the best free signal: revenue falls off steeply with rank, roughly following a power law. Any estimate from rank is rough, often off by a factor of two or three for a single app, so use it to compare ideas rather than to forecast your income.

#What app ideas should indie developers avoid?

Ideas that depend on licensed content, another company's hardware or service, brand searches, or a market where the top two apps hold most of the users. Also be careful with categories where newcomers earn mainly through paid ads, unless you have an ad budget.