ASO for the Apple App Store
Apple App Store optimization means optimizing the four indexed fields Apple reads — the 30-character app name, the 30-character subtitle, the hidden 100-character keyword field and your in-app purchase names — plus the creative that decides conversion. Apple does not index the long description, so description copy affects installs but never rankings. The index treats name, subtitle and keyword field as one pool, so repeating a word across them wastes characters, and Apple automatically combines single terms into phrases. Everything else — custom product pages, in-app events, product page optimization tests and ratings prompts — moves conversion rate, which Apple then feeds back into ranking.
Key takeaways
- Only the app name, subtitle, keyword field and IAP names are indexed by Apple — the description is not.
- Never repeat a word across name, subtitle and keyword field; Apple reads them as a single keyword pool.
- Write the keyword field comma-separated with no spaces, no plurals and no stop words to buy back characters.
- Apple builds phrases automatically from single words, so 'photo,editor' also covers 'photo editor'.
- Conversion rate is a ranking input on iOS, which is why CPPs, in-app events and PPO tests are ASO work, not just design work.
What Apple actually indexes
| Field | Limit | Indexed? | Weight |
|---|---|---|---|
| App name | 30 characters | Yes | Highest |
| Subtitle | 30 characters | Yes | High |
| Keyword field | 100 characters | Yes (hidden) | Medium |
| In-app purchase names | 30 characters each | Yes | Low |
| Promotional text | 170 characters | No | — |
| Description | 4,000 characters | No | — |
| What's New | 4,000 characters | No | — |
| Developer name | — | Yes | Low |
This table is the single most useful thing to internalise about iOS ASO. Teams routinely rewrite a 4,000-character description hoping for rankings and get none, because Apple never reads it for search. The description is a conversion asset: it persuades the minority of viewers who tap 'more'.
Promotional text is the exception worth knowing. It sits above the description, is editable without shipping a build, and is the right place for seasonal or launch messaging — but it earns you no keyword coverage.
How to write the 100-character keyword field
- Separate terms with commas and no spaces — a space costs a character and buys nothing.
- Drop every word already used in your app name or subtitle; the pool is shared.
- Drop plurals. Apple stems, so 'recipe' covers 'recipes' in most locales.
- Drop stop words ('the', 'for', 'with', 'app') and your category name if it already appears elsewhere.
- Use single words, not phrases — Apple recombines them, so 'budget,tracker,expense' covers nine phrase permutations.
- Never include a competitor's trademark; Apple rejects it and it can delay a release.
The Apple-only conversion surfaces
Apple gives iOS teams three conversion tools that have no direct Google Play equivalent, and all three feed back into ranking through install rate.
- Custom product pages: up to 35 alternate pages with their own screenshots, video and promo text, each addressable by URL — built for paid UA and audience-specific messaging.
- Product page optimization: Apple's native A/B test, up to three treatments against the original, split by traffic percentage and reported inside App Store Connect.
- In-app events: time-boxed event cards that surface in search results and on the Today tab, and give you a second indexed title and description per event.
Review guidelines that affect metadata
- Metadata rejections are the most common ASO-related delay: keyword stuffing in the name or subtitle, competitor names, and unsubstantiated superlatives such as 'best' or '#1'.
- Screenshots must show the actual app. Lifestyle-only or mostly-text screenshots without real UI are routinely rejected.
- Price or promotion claims in metadata must be accurate at the time of review, which is why time-limited offers belong in promotional text or an in-app event, not the subtitle.
- Metadata-only changes still require a review pass unless you use promotional text, custom product pages or in-app events, which can be updated independently of a build.
Frequently asked questions
Does the App Store description affect rankings?
No. Apple does not index the description, promotional text or What's New. They affect conversion rate only — which in turn influences ranking indirectly, because install rate is a ranking input.
How many keywords fit in the App Store keyword field?
The field holds 100 characters, which is typically 12 to 18 single words once you remove spaces, plurals and stop words. Apple recombines those words into phrases automatically.
How often can I change App Store metadata?
Name, subtitle and keyword field changes ship with a new app version and go through review. Promotional text, custom product pages and in-app events can be changed at any time without a build.
Is iOS ASO different from Google Play ASO?
Yes. Apple indexes four short fields and ignores the description; Google Play indexes the entire listing including the full description, and weighs engagement and technical quality signals more heavily.
appXL Research
App Store Optimization Research Team
The appXL research team analyzes App Store and Google Play ranking data across the apps our agent manages, and publishes what it finds.