Working notes on App Store optimization
Every post says where each number came from: Apple, a third-party estimate, or nobody outside Apple.
Best apps for iPhone Duo: the three Apple named, and why there is no list
Apple named Netflix, Zoom and Slack and no others, and iPhone Duo reaches a customer on 23 October 2026. Every ranked list before then is guesswork. What is checkable instead.
9 min read
iPhone Duo and your layout: the only opt-in Apple documents is your SDK
No device family, no capability key, no second binary. What Apple documents about laying out an app for a two-display iPhone — and what it has not published.
9 min read
iPhone Duo screenshot sizes, and the note Apple did not write
App Store Connect added iPhone Duo's four screenshot sizes on announcement day, then said uploads open later this year. What Apple documents, and what it does not.
9 min read
App Store Optimization checklist (2026): every field, every cap, in order
A pre-submission checklist in App Store Connect field order — each cap and rule quoted from Apple’s own pages, which four fields Apple says search matches, and what no checklist can tell you.
9 min read
Best free ASO tools in 2026, and what each one cannot tell you
Every ASO tool reads the same public data, and none of them can see impressions, conversion or search volume — only Apple shows you those. A comparison grouped by job, with each vendor's own pricing page as the source.
8 min read
The biggest App Store publishers in 2026, by the numbers
Who the largest iOS publishers are by the one metric that is public — combined lifetime US rating count — computed over 998 seller records on 1 September 2026, with what that number can and cannot say.
9 min read
Free App Store keyword tool: how to research ASO keywords in 2026
What a free keyword tool can actually read from the App Store — Apple's own hints and live results — what it cannot, and a step-by-step method that never needs a search-volume figure.
9 min read
How App Store rankings work, and how to check any app's rank
Apple runs two rankings, chart position and search position, and publishes a formula for neither. What it does document, what it exposes, why the charts move daily, and how to read any app's rank.
9 min read
The App Store Connect API key — one download, ES256, and a token that dies in 20 minutes
Apple's API key is downloadable once, must be signed with ES256, and issues tokens that are invalid beyond 20 minutes. What the docs specify, and how to hold a key that can act on your account.
5 min read
App Store screenshot sizes — you need two sets, not eight
Apple lists dozens of accepted screenshot dimensions, but only two display sizes are required. Everything else scales from what you upload. Here is the chain, from Apple's own reference.
5 min read
The App Store hides a keyword field. Google Play reads your description.
Apple names four text inputs for search, not the description. Google names the description and has no keyword field. Both halves, sourced at each vendor.
8 min read
Apple Search Ads conversion rate: two definitions, one account
Apple defines two conversion rates that share a denominator, and computes both inside your Apple Ads account. What the API returns, and why no public data yields CR.
8 min read
Most of your App Store description is never read, and the cut point is not a number
Apple documents the 4,000-character limit and says nothing about where the text is cut. Here is why no fixed character count can be right, and what one real listing lost above the fold.
5 min read
Real feedback before launch, without risking your developer account
Apple expels developers for manipulating reviews, and the rule is not where it is usually cited. Where the line actually sits, and what to do instead.
8 min read
Giving an assistant real App Store data instead of letting it remember
Ask a model about an app and it answers from memory, confidently and often wrongly. What an MCP server changes, the nine tools this one exposes, and where it still cannot help.
4 min read
How your rivals actually charge, and why you cannot see their prices
Upfront price has nearly vanished from App Store search results — one app in 90 across four measured cohorts. What public data shows about monetization, and what it cannot.
7 min read
In-app events, and the 50 characters that do most of the work
Apple's in-app events have hard limits on length, count and scheduling. Here they are, fetched from Apple's own pages, plus the scheduling mistakes that publish an event nobody can find.
5 min read
k-factor is a pole, not a curve
“Make it go viral” has an exact arithmetic meaning: M = 1/(1-k). A 10% error in k barely matters at 0.3 and completely changes the answer at 0.9.
6 min read
Apple’s own two pages disagree about the keyword field
One Apple page says 100 bytes, another says 100 characters. What Apple documents about the keyword field, where it contradicts itself, and why nobody can read a competitor’s.
9 min read
How many languages your app declares, and why counting them is harder than it looks
The App Store's language field repeats one code, treats empty as unknown, and describes the binary rather than your listing. Three traps in a number that looks trivial.
5 min read
A translated keyword field is why your localized listing ranks for nothing
Apple supports 50 App Store localizations and measures the keyword field in bytes. Localizing a listing is a different job from translating it, and the keyword field is where the difference shows.
6 min read
Minimum iOS and download size: two gates, and two figures nobody can compute
Both sit on your product page where every user sees them. Apple publishes no per-version device share and no current cellular limit — here is what you can compare.
8 min read
Your privacy label covers every SDK you shipped, and Apple says so plainly
Apple's App Privacy questionnaire asks about data your third-party partners collect too. Why the analytics, ads, crash and login SDKs produce most of the wrong answers, and why "linked" must never be answered by default.
6 min read
A rating count with no denominator tells you nothing
Four thousand ratings is excellent for a small app and dismal for a big one. How to give the number a denominator, and the three ways that denominator quietly lies.
6 min read
Your App Store rating is not one number
Apple stores an overview rating per country or region, and most developers only ever look at one of them. What a 58-storefront sweep turns up, and the reset that is not per-country.
5 min read
“Bug fixes and performance improvements” wastes the one place your users are looking
What's New is 4,000 characters shown to people who already installed your app. What Apple documents about it, and the one thing a language model must not do when drafting it.
6 min read
App Store campaign links, and the two ways a launch tag fails silently
Submit to thirty places and downloads rise, but nothing says which one worked. Apple's campaign link rules, and the two failures that show up as nothing at all.
8 min read
The top charts are not your market, and the data says so
Browse any App Store category and household names sit on top. Measured across 1,046 charting apps: 578 are under 10,000 ratings and 309 are under 1,000. They are just buried.
5 min read
The icon decides whether anyone ever reads your screenshots
An icon is judged at about 64 pixels beside ten rivals. Measured colour analysis of a real result row, and why a colour histogram is not allowed to give you advice.
4 min read
Three treatments is three comparisons, and that changes what your PPO result means
Apple's Product Page Optimization allows three treatments and recommends 90% confidence. Run all three and the chance of at least one false winner is 27%, not 10%.
5 min read
Tracking keyword ranks over time, and the one number that tells you if you are up or down
A sparkline per keyword never answers “am I up overall”. The visibility index does, and it is an index — never a share of traffic. Plus the sign error that ruins rank maths.
5 min read
Two of your own apps in one search result is not automatically a problem
SEO cannibalization thinking imports badly to the App Store. What you can observe about two of your listings sharing a result, and the one thing only your own data can settle.
6 min read
If someone asks an assistant about your app, what can it actually read?
Answer engines read what a server sends without running JavaScript. Measured on this site — 2,169 words on a prerendered page, and the homepage on every route that is not.
5 min read
What is App Store optimization? The short answer, and the parts Apple actually documents
The most-searched question about ASO, answered from Apple's own pages — which fields Apple says it matches on, which it never mentions, and how much of the rest is folklore.
5 min read
What it takes to reach an App Store chart, and why every number for it is an estimate of an estimate
Apple publishes no chart formula and no download figures. What the charts really are, measured live, and why downloads-to-rank is a guess on a guess.
8 min read
Two of the venues on your launch list ask you not to paste generated text
Hacker News and Product Hunt each publish a rule against generated text. What every venue on a launch list actually allows, quoted from the source.
8 min read
Most posts end at a tool that does the work. Browse every free App Store optimization tool, or read the ASO guide end to end.