How App Store indexing works: name, subtitle, keyword field
Which fields the App Store uses to find an app, how many characters they hold, how to fill in the keyword field, and why being indexed does not yet mean ranking.
An app shows up in App Store search only for the queries it is indexed for. The index is built from a small set of fields. If a word is in none of them, the app will not be found for that word, however much traffic it gets.
What App Store search takes into account
Apple puts it this way: search results depend on text relevance and on user behaviour.
- Text relevance: matches for the app's name, subtitle, keywords and primary category.
- User behaviour: downloads, ratings and reviews, and more.
Promotional text does not affect search, so putting keywords there is pointless.
How much room there is for keywords
| Field | Limit |
|---|---|
| Name | 30 characters |
| Subtitle | 30 characters |
| Keyword field | 100 characters |
That is 160 characters in total, and the name and subtitle still have to read well.
How to fill in the keyword field
- Commas, no spaces. The limit counts characters, so a space after a comma is a wasted character.
- Don't repeat words from the name and subtitle. They are already indexed.
- Single words beat phrases. Search combines the words it finds in your metadata by itself.
- No other brands. Apple calls improper keywords a common reason for rejections and explicitly rules out competing app names, unauthorised trademarks and irrelevant terms.
Locales and storefronts
Each language in App Store Connect has its own name, subtitle and keyword field, and each storefront takes the metadata of several locales into account. That is why classic ASO spreads keywords across extra locales to get more room. It works, but every locale has to be filled in, maintained and sent through review with a new version.
When changes reach search
The name, subtitle and keywords change only with a new app version. A version goes through review: Apple says it typically reviews at least 50% of submissions in less than 24 hours and 90% in less than 48 hours. After release, search needs more time to pick up the new words.
Indexing and position are different things
To be indexed is to appear in the results for a query. Where you appear is decided by user behaviour: how many people install your app from that query. There is a separate article on this: Indexed but not ranking.
When the metadata is not enough
We write extra keywords without an app update: up to 100 characters per order, one shared field for all storefronts, in search in about 2 hours. See How to index an iOS app for new keywords without an app update or send an order straight away.