App Store Optimization (ASO)
App Store Optimization is the process of improving an app's visibility in App Store search results and its conversion rate from search impressions to installs.
App Store Optimization covers two separate problems: getting the app to appear in search results (discoverability), and getting users who see the app to tap the install button (conversion). Most ASO tools focus on discoverability because it can be measured with data; conversion depends on screenshots, preview videos, and ratings that are harder to score at scale.
The primary levers for discoverability are the metadata fields Apple indexes for search: the app name (30 characters), subtitle (30 characters), and keyword field (100 characters). Title and subtitle carry more weight than the keyword field — a well-chosen title term is worth more than the same term buried in the keyword field.
Keyword research is the foundation of ASO. Before writing any metadata, you need two numbers for each candidate keyword: how much demand it has (popularity) and how hard it is to rank for given the apps currently occupying the top results (difficulty). Without both numbers, you are choosing between keywords on instinct.
ASO is ongoing, not a one-time task. Apple's popularity scores shift as search behaviour changes, and ranking difficulty changes as competitors update their metadata. Checking your keyword set before each major update is the minimum viable cadence.
Frequently asked questions
- What does App Store Optimization actually change?
- ASO changes the text fields Apple indexes for search — primarily the app name, subtitle, and keyword field. Changes to these fields affect which search terms your app appears for and where it ranks. It does not change your app's code, its rating, or how Apple's editorial team features it.
- How long does it take to see ASO results?
- Apple typically re-indexes metadata within a few days of an app update. Ranking changes are visible within a week for most terms, but reaching the top positions for competitive keywords can take months of incremental improvements and installs that signal relevance.
- Is ASO the same for the App Store and Google Play?
- No. The two stores have different ranking algorithms, different metadata structures (Google Play indexes the full description; the App Store does not), and different popularity signal sources. Research and optimisation must be done separately for each store.
Related terms
- Keyword PopularityKeyword popularity is a 0–100 score measuring how often users search for a given term in the App Store, derived from Apple Search Ads demand signals.
- Keyword DifficultyKeyword difficulty is a 0–100 score estimating how hard it is to break into the top-ranking positions for a given App Store keyword, based on the strength of apps currently holding those positions.
- App Store Search Ranking FactorsApp Store search ranking factors are the signals Apple's algorithm uses to determine which apps appear at the top of results for a given keyword — primarily metadata relevance, user engagement, and app quality indicators.
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Put this into practice
Score App Store keywords by popularity and difficulty across 109 storefronts — the numbers behind app store optimization (aso).
Start keyword research