App Store Optimization (ASO)
The process of improving an app's visibility and conversion rate in mobile app stores like the Apple App Store and Google Play.
ASO is a continuous discipline, not a one-time launch task. The main levers are keyword targeting, metadata quality (title, subtitle, keyword field, description), visual assets (icon, screenshots), and ratings/reviews. Effective ASO compounds: small improvements to title and subtitle keywords can lift impressions by double-digit percentages, and conversion improvements on the product page multiply through every impression.
Keyword Research
The process of identifying which App Store search terms a target audience uses and which of those terms an app has a realistic chance of ranking for.
Useful keyword research compares three dimensions per term: search volume (demand), difficulty (how hard it is to rank), and trend/seasonality. The best targets are usually mid-volume, low-to-medium difficulty keywords where competitors have weak metadata coverage.
Rank Tracking
Daily monitoring of where an app appears in App Store search results for specific keywords in specific countries.
Rank tracking establishes a baseline before metadata changes and measures the lift afterwards. Tracking should be per-country (rankings differ massively across storefronts) and ideally daily, since rank can move significantly day-to-day from factors like new competitor releases, featuring, or seasonal demand spikes.
App Store Metadata
The text and visual fields Apple indexes for App Store search: title (30 chars), subtitle (30 chars), keyword field (100 chars), description (4,000 chars), and promotional text.
The title and subtitle carry the heaviest ranking weight. The keyword field is invisible to users but indexed by Apple — it should never repeat words already in the title or subtitle, since repetition is wasted character budget. The description and promotional text are not indexed for ranking but heavily affect conversion.
Keyword Field
A hidden 100-character field in App Store Connect that Apple indexes for App Store search but does not show to users.
Comma-separated, with no spaces around commas to save characters. Singular forms generally cover plurals. Words in the title or subtitle should not be repeated here. Localized per language: each storefront has its own 100-character budget.
Subtitle
A 30-character field directly below the app name in App Store search results and on the product page. Indexed by Apple for ranking.
The subtitle is the second-strongest ranking signal after the title. It should describe the app's primary use case in plain language and include at least one secondary high-value keyword. Avoid repeating words from the title — that wastes ranking weight.
App Store Conversion Rate
The percentage of users who download an app after seeing its product page or search result.
Apple App Analytics splits this into impression-to-product-page rate and product-page-to-install rate. Improving conversion rate compounds organic growth: every keyword ranking translates into more installs without changing the ranking itself.
App Store A/B Testing
Running controlled experiments on App Store assets (icon, screenshots, description) to measure which variant produces more installs.
Apple's built-in tool is called Product Page Optimization (PPO). It splits live traffic across up to three variants and reports installs and a statistical confidence interval. A test typically needs several thousand impressions per variant before results become reliable.
Product Page Optimization (PPO)
Apple's native App Store A/B testing tool for icons, screenshots, and app previews.
PPO lets you run up to three variants against the default page for a fixed traffic share over a defined window. Reports include installs per variant and a confidence interval. PPO does not test text fields like title, subtitle, or description.
Custom Product Page (CPP)
An App Store product page variant with custom screenshots, promotional text, and app previews, linkable via a unique URL.
Custom Product Pages let teams target ad campaigns, partnerships, or specific user segments with tailored creative without changing the default page. They also rank in App Store search for the page-specific custom screenshots and copy.
Impression-to-Install Rate
The percentage of App Store impressions that result in an app install, combining search-result tap-through and product-page conversion.
Apple App Analytics calculates this as a multiplicative funnel: impressions → product page views → installs. Improving either step compounds the total. A baseline rate of 2–5% is common; well-optimized apps reach 10%+.
Keyword Difficulty
An estimate of how hard it is for a new app to rank in the top 10 for a given App Store keyword.
Calculated from the strength of currently-ranking apps for that term: ratings count, total installs, keyword coverage in titles/subtitles, and brand authority. Indie apps generally target keywords with low or medium difficulty rather than competing head-to-head with established brands.
Search Volume
An estimate of how often App Store users search for a specific keyword, expressed as a 0–100 popularity score in most ASO tools.
Apple does not publish absolute search counts. ASO tools approximate volume from observed ranking competition and Apple's own "Apple Search Ads popularity" signal, which uses a 5–100 scale. A score of 50+ is meaningful traffic; a score below 20 is rarely worth targeting unless conversion is exceptional.
App Store Localization
Translating and adapting an app's App Store metadata (title, subtitle, keyword field, description, screenshots) for each storefront language.
Localization is one of the highest-ROI ASO activities for apps already getting impressions in international markets. Each language adds a separate 100-character keyword budget, separate title and subtitle slots, and access to local search terms that direct translation often misses.
Competitor Analysis
Systematic comparison of an app against competitors across keywords, metadata, ratings, and visibility to find gaps and opportunities.
Competitor analysis answers two questions: (1) Which keywords do competitors rank for that we don't? (2) What metadata patterns correlate with their ranking strength? The output is a prioritized list of keyword and metadata experiments.
App Store Connect (ASC)
Apple's web portal and API for managing iOS, iPadOS, macOS, watchOS, and tvOS apps on the App Store.
ASC is where metadata is submitted, builds are uploaded via Xcode or Transporter, screenshots are managed, and sales/analytics data is accessed. Most third-party ASO tools, including Marteso, integrate via the App Store Connect API with read-only or scoped access.