App store optimization (ASO) is the work of getting more people to find your app in the App Store and Google Play, and then getting more of the people who land on your listing to install it.
It has two halves: visibility (keywords, metadata, ratings) and conversion (icon, screenshots, video, reviews).
Most guides focus on keywords; this one gives equal weight to conversion, because that is the half you can test and measure directly.
Below we cover what ASO means, how each store works, how to run listing experiments on both platforms, and what the subscription-app tests in our database suggest about the listing elements that tend to move people.
What is ASO? Visibility plus conversion
ASO stands for app store optimization. It is the app equivalent of SEO plus landing-page conversion work, done inside a store you don't control.
It helps to think of ASO as a simple equation: installs from the store = impressions × conversion rate.
Visibility work raises impressions. Conversion work raises the share of those impressions that turn into downloads.
- Visibility: where you rank in store search, which keywords you show up for, whether you get featured, and what category you sit in.
- Conversion: what people see in search results and on your product page, and whether it convinces them to tap Get or Install.
The two halves feed each other. Both stores factor in how users respond to your listing, so a page that converts better can help how you rank.
And better rankings bring traffic that is only worth having if the page converts it.
How much room is there? Apple says the average conversion rate on default product pages is 1.6%.
For more context, see our app store conversion rate benchmarks.
Keywords and metadata: the visibility side, briefly
Keyword work is about choosing the words people actually type and putting them in the fields each store reads. The fields and limits differ by store.
App Store metadata
Apple gives you an app name and a subtitle of 30 characters each, plus a hidden keyword field of 100 characters.
Keywords are separated by commas with no spaces between terms.
There is also a 170-character promotional text field that you can update without a new release.
Because space is tight, don't repeat words across the name, subtitle and keyword field.
Use the subtitle for the clearest one-line benefit, since people read it in search results.
Google Play metadata
Google Play gives you an app name of 30 characters, a short description of 80 characters and a full description of up to 4,000 characters.
Google warns that repetitive or irrelevant keyword use in these fields can get an app suspended.
Play's metadata policy also bans ranking claims such as "#1" or "Best of Play," price promotions such as "10% off," emojis, and all caps (unless it's part of your brand) in titles, icons and developer names.
Tools for keyword research
You can do basic research by typing seed terms into store search and noting the autocomplete.
For volume estimates, difficulty scores and competitor tracking, most teams use a paid tool.
We compare the main options in our ASO tools roundup and go deeper in our AppTweak review.
The conversion side: icon, screenshots, video, ratings
Most people decide from the search result card, not the full product page.
On the App Store, the first one to three screenshots appear in search results.
That makes your icon, your first screenshots and your star rating the main levers.
Icon
The icon appears everywhere: search, charts, the home screen.
It needs to be readable at small sizes and stand out from the icons next to it in search results.
On Google Play, the store icon is 512 × 512 px, a 32-bit PNG of up to 1024 KB.
Our app icon guide covers design patterns and tests.
Screenshots
Apple allows up to 10 screenshots. Google Play allows up to 8 screenshots per device type and needs at least 2 to publish.
In practice, screenshots work as an ad, not a gallery: one benefit per frame, a short caption, and the most important promise first.
Common patterns worth testing:
- Lead with the outcome ("Fall asleep faster") rather than the feature ("Sleep sounds library").
- Put social proof or a key stat in the first or second frame.
- Make the first two frames read as one panoramic image so people swipe.
- Localize captions, not just the store text.
See our screenshot guide for examples, and the screenshot size reference for each device.
Preview video
On the App Store you can add up to three app previews of up to 30 seconds each; they autoplay muted.
Because they autoplay without sound, the first few seconds need to work with captions and no audio.
Google Play uses a YouTube link that must be public or unlisted, embeddable and have ads turned off. More in our preview video guide.
Ratings and reviews
Ratings show up next to your icon in search, so they affect conversion before anyone opens the page.
Apple lets you prompt users up to three times in a 365-day period with its native rating prompt, so pick the moment carefully, ideally right after a success in the app.
If an old version left you with a poor score, Apple lets you reset your summary rating when you release a new version.
The reset is global and can't be undone, and written reviews stay visible.
On Google Play, the rating users see is weighted toward your most recent ratings, so fixing the product tends to show up in the score over time.
App Store vs Google Play: what's different
The same ASO approach works on both stores, but the mechanics differ enough that you should plan them separately.
| Element | App Store (iOS) | Google Play |
|---|---|---|
| Title | 30 characters | 30 characters |
| Second text field | Subtitle, 30 characters | Short description, 80 characters |
| Keywords | Hidden keyword field, 100 characters | No keyword field; uses your listing text |
| Long description | Shown on the page; the first sentence matters most | Up to 4,000 characters |
| Screenshots | Up to 10 | 2 to 8 per device type |
| Video | Up to 3 previews, 30 seconds each, autoplay muted | One YouTube video |
| Extra graphic | None | Feature graphic, 1024 × 500 px |
| Native A/B testing | Product page optimization: up to 3 treatments, 90 days | Store listing experiments: up to 2 variants vs current |
| Alternate listings | Up to 70 custom product pages | Up to 50 custom store listings |
Sources: Apple product page, Apple PPO, Apple custom product pages, Play text limits, Play preview assets, Play experiments, Play custom store listings.
The biggest practical difference for Google Play app store optimization: Play has no hidden keyword field, so the words in your title, short description and full description do the keyword work.
Write the full description for people first, but make sure your main terms appear naturally.
On iOS, the hidden keyword field lets you target terms without putting them in visible copy.
That makes the visible text free to focus on conversion.
Testing your listing: PPO, Play experiments and custom product pages
Both stores now have built-in A/B testing, which is the main reason ASO conversion work no longer needs guesswork.
Product page optimization (App Store)
Apple's product page optimization lets you test up to three alternate versions of your page against the original.
You can test the icon, screenshots and app previews.
Tests run for up to 90 days, and you choose what share of traffic goes into the test.
New screenshots, previews and icons must pass App Review before the test can start, and every alternate icon has to be included in the app binary.
Apple suggests waiting until a treatment reaches 90% confidence before acting on it.
Our guide to product page optimization walks through setup.
Store listing experiments (Google Play)
Google Play's store listing experiments test up to two variants against your current listing.
You can run one default graphics experiment (icon, feature graphic, screenshots) or up to five localized experiments at once, and localized tests can include your descriptions too.
That makes Play the only one of the two stores where you can test description text natively.
Experiments stop automatically after six months, and Google recommends changing one asset at a time so you know what caused a result.
Custom product pages and custom store listings
These aren't A/B tests, but they let you match the page to the audience.
Apple allows up to 70 custom product pages, each with its own screenshots, previews and promotional text.
You can send ad traffic to them by URL, and you can assign keywords so a custom page shows in search for those terms instead of your default page.
Apple reports that developers see a 2.5 percentage point increase on average when they send people to a custom product page, a 156% increase over the 1.6% average for default pages.
That's Apple's own figure, with no date range or method published.
Google Play allows up to 50 custom store listings, targeted by country, URL, Google Ads ad group, search keywords, pre-registration or user segments such as churned users. See our custom product pages guide.
Testing tips
- Test the first screenshot or the icon first. They are seen by the most people.
- Make variants clearly different. Small tweaks rarely reach confidence on store traffic.
- Watch what happens after the install. A listing that wins on installs can still lose on trials and revenue if it attracts the wrong users.
- Check seasonality and paid campaigns. A burst of ad traffic during a test can skew results.
What the database says works
A note on honesty first: our app database is built mostly from paywall, onboarding and retention tests.
We don't yet have many published store-listing tests with clean numbers.
When we add them, they'll appear on the store listing tests page.
What we do have is a lot of evidence on how subscription-app users respond to video, localization, proof and previews just after install.
Those are the same tools a store listing uses, one screen earlier. Here's what transfers.
Video can move people, but test it
FitnessAI saw about +80% revenue after adding video to its paywall (a before-after comparison, reported in a RevenueCat article).
Stardust's video background paywall lifted paywall conversion 67% and proceeds per user 12.5% in a vendor-reported Superwall case study.
The counterpoint comes from ecommerce: one store replaced a homepage hero video with a static image and a benefit callout and saw +52.67% revenue per visitor.
Video isn't automatically better. That's why the preview video is a good first PPO test.
Localization pays off
Daily Horoscope reported a +183% trial start rate with paywalls localized by country, and Photoroom saw +50% upsell screen conversion from localized upsell paywalls (both vendor-reported).
If localized screens convert that much better inside the app, translated screenshot captions are worth testing in your biggest non-English markets.
Play's localized experiments and Apple's per-locale PPO treatments make that possible.
Proof and a clear promise help
A food app that added a review and a results stat to a short paywall saw +72% install-to-trial, in a bundled redesign by Vahe Baghdasaryan.
In ecommerce, putting the star rating and review count above the product title lifted conversion 8.14%.
On a store listing, the same ideas map to a proof frame in your first screenshots and a healthy star rating in search.
Show the product, and order matters
Unchaind's paywall that previews premium features got over +50% conversion and +64% estimated ARPU (vendor-reported).
Screenshots do the same job: show what the user gets, not just a logo and a slogan.
Order matters too. An ecommerce test that simply moved the second product photo into first place in the gallery raised revenue per visitor from £3.32 to £3.60. Your first screenshot is your first gallery image, so test which frame leads.
Match the page to the audience
Flirt AI reported +83% MRR in 30 days and +20% trial-to-paid by picking paywalls based on demographics, and JourneyStamp saw +50% conversion with paywalls matched to the user's context (both vendor-reported, both bundled changes).
Custom product pages and custom store listings apply the same idea before the install: a different first screenshot for each ad campaign or keyword theme.
The listing is the start of onboarding
Teaching.com tested onboarding on the web before download and saw about +50% conversion to trial and about +30% conversion to paid (reported on the RevenueCat blog).
Users who had already seen what the app would do for them before installing were more ready to commit.
A store listing can do a lighter version of that job.
If your screenshots show the first steps a user will take and the result they'll get, the onboarding that follows feels like a continuation rather than a surprise.
Don't win installs you can't keep
BoldVoice's hard paywall with no close button got more trial starts, but refunds rose by more than the gain.
Listings carry the same risk: overpromise in screenshots and you'll get installs that churn or refund.
Judge listing tests on trials and revenue, not just installs.
The full install-to-paid path is covered in our onboarding and paywall guides.
A simple app store optimization strategy
If you're starting from scratch, this order works for most subscription apps:
- Fix the basics. Fill every metadata field, use all screenshot slots, and add a preview video on iOS.
- Pick 10 to 20 target keywords that match what your app does, and place them in the right fields for each store.
- Rewrite the first three screenshots around outcomes, with one proof element.
- Run your first test on the first screenshot or icon using PPO or Play experiments.
- Build custom pages for your largest ad campaigns or keyword themes.
- Review monthly: rankings, conversion rate by source, and ratings.
Our ASO checklist turns this into a step-by-step list.
Common ASO mistakes
- Stuffing keywords into visible text. It reads badly, and Google says repetitive keyword use can lead to suspension.
- Treating screenshots as a feature tour. People scan the first frames in a second or two. If those frames don't state a benefit, the rest rarely gets seen.
- Calling a test too early. Store traffic swings by day of week and with paid campaigns. Let tests run until the store's own dashboard shows confidence.
- Measuring installs only. A listing that pulls in curious but unqualified users can lower trial and paid conversion further down the funnel.
- Ignoring the rating prompt. With only three native prompts a year on iOS, asking at a random moment wastes them.
- Setting and forgetting. Competitors change their listings, and search terms shift with seasons. Revisit keywords and creative at least every quarter.
When to hire an ASO agency
Many small teams can handle ASO themselves with a keyword tool and the native test features.
An agency starts to make sense in a few situations:
- You're launching in many languages at once and need native-speaker keyword research.
- Store search is a major install source and you've stopped gaining ground on your own.
- You don't have a designer who can produce several strong screenshot sets for testing.
- You run large paid campaigns and want custom product pages built and tested for each one.
An agency is probably not worth it if your app has very low traffic (tests won't reach confidence), if the product itself has rating problems that the listing can't fix, or if you haven't done the basics yet.
When you talk to agencies, ask to see past test results with the method and run time, ask who will do the design work, and ask how they'll measure results beyond installs. Our ASO agency directory lists options.