No one outside Apple and Google knows exactly how their search algorithms work. But the ASO community has been running experiments for over a decade, and the patterns are consistent enough to act on. Here's the current understanding of what drives app search ranking.
Keyword Relevance: The Foundation
The most fundamental ranking factor is whether your app is even eligible to rank for a given query. If the search term doesn't appear in your indexed metadata fields, you have no chance of ranking — regardless of how many downloads you have.
On iOS: title, subtitle, and keywords field are indexed. On Google Play: title, short description, and long description are indexed. Getting the right terms into these fields is table stakes. Everything else only matters once you're in the eligibility pool.
Conversion Rate as a Quality Signal
Both stores use conversion rate (what percentage of users who see your app in search results actually download it) as a ranking signal. High conversion rate signals that your app is satisfying user intent for that query — which is exactly what the stores want to optimize for.
This creates a compounding dynamic: better screenshots and copy improve conversion rate, improved conversion rate improves ranking, improved ranking drives more impressions, more impressions create more download data that further validates your ranking. The virtuous cycle is real.
Download Volume and Velocity
Raw download count matters as a ranking signal — apps with more downloads rank higher, all else equal. But velocity (rate of new downloads over a recent time window) often matters more than total. A new app getting 500 downloads per day is more likely to rank prominently than an old app with 1 million lifetime installs but declining momentum.
Ratings and Reviews
Average rating and review count are ranking factors. More specifically, recent ratings carry more weight than historical ones. An app with a 4.8 average from the past 90 days ranks better than one with a 4.8 lifetime average that's been getting 3-star reviews recently.
Review frequency also matters — apps that consistently receive new reviews signal ongoing active usage to the algorithm. This is one of the non-keyword reasons that in-app review prompts drive more than just social proof: they produce the regular review cadence the algorithm rewards.
Engagement Signals
Both Apple and Google track post-download behavior. If users download your app and immediately delete it (or never open it past the first session), that signal reaches back and affects your ranking for the keywords that drove that traffic. High churn from a specific query term can suppress your ranking for that term.
Developer Account Quality
Apple considers your overall developer account standing. Apps from accounts with a history of guideline violations, spam apps, or fraudulent activity face ranking suppression. Conversely, developers with a long track record of quality apps may see a slight ranking benefit when launching new apps — the "halo effect" of account authority.