App Store Optimization (ASO) Guide

App Store Optimization (ASO) is the process of improving an app's visibility and conversion rate in app stores such as the Apple App Store. Good ASO helps the right users discover your app through search and browse, and convinces them to install once they land on your product page. It is often described as "SEO for apps".

ASO has two halves that feed each other: visibility (ranking for the searches your users actually type) and conversion (turning an impression into an install). Apple's ranking algorithm rewards conversion, so a better-converting product page also ranks higher over time.

The majority of App Store downloads begin with a search in the store. Because organic installs are essentially free, even small ASO improvements compound over time. For indie developers with limited ad budgets, ASO is frequently the single most cost-effective growth channel — and unlike paid ads, gains persist after you stop spending.

Apple's search index reads a handful of short fields. Knowing which ones rank — and which don't — is the difference between effective metadata and wasted characters:

Developer name and in-app purchase / in-app event names are also indexed. The description and promotional text are not — write them for humans.

Keywords are the foundation of ASO. Identify the words and phrases your ideal users type when looking for an app like yours, then study which keywords your competitors already rank for. Prioritise keywords with meaningful search volume and realistic competition — as a new app you will rarely crack the top 10 for "photo editor", but you can own "vintage film photo editor".

A practical workflow: list 5–10 direct competitors, extract the keywords in their names and subtitles, expand with App Store search autocomplete suggestions, and then check where each app actually ranks for each candidate keyword.

You can do this in minutes with the Appstro App Store keyword tool.

Your app name (up to 30 characters) and subtitle (up to 30 characters) carry the most ASO weight on the Apple App Store. Lead with your brand, then include your most important keyword naturally: "Brand — top keyword phrase" is the pattern most successful apps use.

Avoid keyword stuffing — Apple rejects spammy names, and clarity converts better anyway. The subtitle should complement the name with your second keyword theme, not repeat it: repeated words gain nothing, so every repeated word is a wasted slot.

Apple gives you a hidden 100-character keyword field. Rules that maximise it:

• Separate keywords with commas, without spaces after the comma.
• Never repeat words already in your name or subtitle — they're already indexed.
• Use single words over phrases: Apple combines words across fields to match phrases.
• Skip plurals when you already have the singular (and vice versa).
• Don't waste characters on "app", "free", "iphone" or your category name.

Review this field at every release: swap out keywords you rank poorly for and double down on themes where you're climbing.

Visual assets drive conversion. A clear, distinctive icon and benefit-led screenshots turn impressions into installs. Because conversion rate feeds back into rankings, strong creative is part of ASO, not separate from it.

You can upload up to 10 screenshots per device size — but the first 3 do almost all the work, since that's what shows in search results. Lead with your strongest benefit as a short caption, not a feature list. App preview videos autoplay in results and can lift conversion significantly for visual products like games.

Higher ratings improve both ranking and conversion — most users filter out anything below 4.0 stars mentally. Prompt happy users to rate the app at the right moment (after a success moment, never at first launch), respond to negative reviews, and watch sentiment over time.

Reviews are also free product research: complaints cluster around the features worth fixing, and praise tells you what to lead with in screenshots. Apple lets you reset your rating with a new version — use it only after genuinely fixing what dragged the score down.

Localising your metadata for different storefronts can unlock large amounts of new organic traffic. What ranks in the United States may differ completely in Japan, Germany or Brazil — research keywords per country rather than assuming one list fits all 55+ markets.

A little-known trick: some storefronts index additional language metadata (for example, the US storefront also indexes Spanish (Mexico) metadata), effectively doubling your keyword space. Even without translating the app itself, localised metadata alone can lift downloads in secondary markets.

Beyond core metadata, Apple offers three growth surfaces most indie developers underuse:

• In-app events — up to 5 published at once; event names are search-indexed and events get their own placements in search and on your page.
• Custom product pages — up to 35 alternate pages with their own screenshots and promotional text, each with a unique URL for ad campaigns and social links.
• Product page optimization (PPO) — native A/B testing of up to 3 treatments against your default page. Test one variable at a time (icon, first screenshot, subtitle) and ship the winner.

ASO is continuous, not one-and-done. Track your keyword rankings, ratings and category position, change one variable at a time, and keep the winners. Treat your product page as something you optimise every release.

A simple cadence that works: review keyword rankings monthly, refresh the keyword field each release, re-run competitor research quarterly, and re-test creative whenever conversion dips.

• Stuffing the description with keywords — Apple doesn't index it.
• Repeating the same word across name, subtitle and keyword field.
• Targeting only huge head keywords a new app can't rank for.
• Copying a US keyword list to every storefront untranslated.
• Asking for a rating on first launch, before the user has seen value.
• Changing five things at once, so you can't tell what moved the needle.