A complete guide to app store optimisation

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App store optimisation best practice for Apple’s App Store and Google Play – the two biggest mobile app stores on the market – and their key ranking factors.

With the vast majority of smartphone usage spent on mobile apps (86% in the UK alone), conquering one of the major app stores is a tempting prospect for any brand with big mobile ambitions.

You might assume most of that time is gobbled up by Instagram and the leading social apps, but social media didn’t even make it into the top five Android app categories of 2019. Tools, communication, business, video players and editors, and travel and local rounded up the top five categories, proving there’s a sizeable market beyond social media apps.

In this article, we explain how to optimise your mobile app for the major app stores, maximise your presence and convince more users to download your application.

What is app store optimisation?

App store optimisation (ASO) is the process of optimising the listing of your mobile app for app stores like Google Play and the iOS App Store. The aim is to make your app as discoverable as possible on these platforms and maximise downloads.

Essentially, this is the mobile app equivalent of SEO for a website. You’ll see the optimisation process is quite similar too.

Showing apps in the app store

The phrase app store optimisation (ASO) is widely used in the marketing industry and it specifically refers to the listing that appears in app stores. Just like SEO, there are performance aspects that impact the ranking of your app and we’ll look at these in detail a little later in this article.

Keep in mind that, on a more technical level, you also need to meet the review guidelines of each individual app store before your listing will appear at all.

Check out our app store optimisation service if you need help with your app.

How do I optimise for an app store?

If you’re familiar with optimising a website for search, the general process for optimising for an app store will feel very familiar. So, in this section, we’re going to look at the key aspects of optimising for Apple’s App Store and Google Play – the two biggest mobile app stores on the market.

Title / app name

In the same way that page titles are one of the most important ranking factors in SEO, the title of your app listing is equally important for app store optimisation – and the same general rules apply.

Your title should first include the name of your app and, assuming you have enough space left, you should also include your main keyword in a way that accurately describes your app.

Let’s imagine someone searches for “productivity apps” in Google Play and sees a list of results that looks something like this:

Example of productivity apps

Here you can see each app specifies its name in the title and also a brief description that includes their main keyword and provides valuable context for the user. If the name of your app happens to be descriptive and includes your primary keyword, you can simply use this as your title and move on – for example, a snooker game named Virtual Snooker Champion.

Subtitle (iOS)

In Apple’s App Store you can also add a subtitle that displays under the title/name of your app in search results and the listing page.

Showing title and subtitle in the app store

As a quick note, Apple doesn’t value keyword density in its algorithm so there’s no point in repeating your primary keyword in the subtitle. More importantly, it doesn’t benefit users to see the same words repeated, so use this space to describe your app in a little more detail and include any important secondary keywords where suitable.


Choosing the right categories for your app is essential for showing up in relevant searches. Go back to the “productivity app” search example we looked at before and you’ll see very few of the apps listed actually include the keyword “productivity”.

However, the apps still show for this search thanks to the right choice of category, allowing developers to target more specific search terms in their title and app descriptions. Keep in mind that the criteria for choosing app categories vary a little between the App Store and Google Play, so make sure you’re familiar with the guidelines.

You can find instructions for the App Store here and Google Play here.


Apple provides a keyword field with a limit of 100 characters, where you can list the most important keywords for your app. Again, you can find documentation on the App Store developer centre but here’s a summary of what Apple has to say about using the keyword field.

“Keywords are limited to 100 characters, so it’s important to be concise when describing your app. While spaces should not be used before or after the commas that separate keywords and keyword phrases, you can use spaces to separate words within keyword phrases. For example: Property,Real Estate,House.”

Choose your keywords based on the terms you think your target audience will use to find your app in the App Store. You’ll have to weigh up the pros and cons of targeting broad keywords to try and maximise visibility and being more specific to increase relevancy and hopefully, downloads.

Google Play is more complex in how it deals with keywords; there’s no field for you to specify search terms. Instead, you have to rely on your title, category and the keywords in your app description.

App description

The app description in the iOS App Store isn’t a ranking factor. You simply need to use this space to provide a relevant, accurate and compelling description of your app. Things are very different in Google Play though, where Google’s advanced algorithm crawls your description for contextual meaning.

This means you want to include keywords in your description and aim for a density of around 2-3%. You may need to spend more time optimising your description too, to find the right balance in terms of ranking in Google Play and providing the best description for users.

Images and screenshots

Images and screenshots don’t provide any direct ranking benefits but they do have a major impact on CTRs, downloads and performance metrics that do impact your ranking. More importantly, they play a big role in determining how many people decide to download your mobile app.

Images should be accurate, relevant and compelling. Your aim here is to show users why they should choose your app from the dozens or hundreds of alternatives, so do what you can to highlight the key benefits and USPs of your mobile app.

If you’re targeting multiple language locations with your app, make sure you also include localised images for each listing with UI elements featuring the native language of each audience.

You don’t want users in France seeing images of your app’s user interfaces in English.

App Previews / Promo Videos

Both the App Store and Google Play encourage you to include short videos showing what your app can do. Apple calls these App Reviews and Google calls them Promo Videos. Once again, the guidelines for these vary so make sure you’re familiar with the requirements before you create any footage.

Previews in the app store

Apple has particularly strict restrictions in place (a common theme on the App Store) and you’ll find an in-depth summary here.

Google gives you much more freedom with its Promo Videos, which are basically YouTube videos that you can embed in your listing. There are some guidelines you need to meet but these are mostly technical specification requirements, which you can read up on here.

Above all, you want to create a video that demonstrates the key benefits of your app and the positive experience users can expect when they download it.

User reviews

If there’s anything more important than images and video previews, in terms of convincing people to download your app, it’s going to be user reviews. This is especially important on Google Play where the quality of mobile apps varies much more than on the App Store – the benefit of Apple’s strict review guidelines.

Google Play also has a much larger library of apps for users to explore and the positive reviews can be the crucial deciding factor.

Imagine users’ dismay when they see the review score for the new Starbucks UK app with its measly 1.8 out of 5 review score.

Starbucks app showing 1.8 stars out of 5

It only gets worse as users scroll down and see the feedback people are leaving for the replacement of one of the most successful mobile apps in history. Not to mention the fact that both Google Play and the App Store will recommend alternative options with better review scores.

Starbucks app bad reviews

Maybe this won’t be enough to convince die-hard Starbucks customers to switch brands, but few brands enjoy the same level of loyalty. For the vast majority of businesses with a mobile app, positive reviews have a major influence on CTRs and downloads – and they likely mean your app delivers an experience that will keep people using it happily after the initial download.

What are the ranking factors in major app stores?

Now that we’ve looked at the key aspects of your app listing that need to be optimised, let’s run through the key ranking factors for the App Store and Google Play. This is worth understanding because some listing features we’ve looked at have a direct impact on your ranking while others don’t – and there are some ranking factors we haven’t explored at all yet.

Here’s a quick summary of the known ranking factors on both platforms.

App StoreGoogle Play
App nameApp title
SubtitleShort description
App URLLong description
Keywords (app name, keyword field)Keywords (all inputs), incl. keyword density
Ratings & reviewsRatings & reviews
Listing CTRListing CTR
 Google Tags
App performanceApp performance
Uninstall rateUninstall rate
In-app purchasesIn-app purchases
 Quality backlinks

As you can see, the known ranking factors look very similar across the two platforms, with a few exceptions on the listings. That said, both app stores have their own algorithms with unknown or unconfirmed ranking factors. Google Play comes with the added complexity of integrating with Google Search and other products from the world’s biggest search engine.

The thing to keep in mind at this point is that both platforms look at the same performance signals of your app and this has a big impact on how highly you rank.

The role of UX and performance signals

To understand the importance of user experience and performance signals in app store optimisation, it helps to know how platforms like Apple’s App Store and Google Play make money.

In the case of Apple, the App Store is a significant source of revenue for the company, generating billions of dollars every year – around $15 billion (£12bn) in 2019. Most of this money comes from in-app purchases where the company takes a sizeable 30% cut from each transaction, while the remaining 70% goes to the app’s developers.

The story is a little more complex with Google Play. Google generates most of its Android money from mobile advertising, including the ads that are shown in the huge library of free apps available on Google Play. The tech giant’s second-largest stream of revenue comes directly from app purchases and, just like Apple, Google takes a 30% cut on all apps bought via Google Play and purchases made inside apps.

So, while the revenue structures are a little different for Apple and Google, both app stores need users to download apps, keep using them and continue to make purchases (and click on ads, in the case of Google Play).

With this in mind, here’s what the performance signals above listed really amount to:

  • Downloads: Opportunities for app stores to generate revenue.
  • Uninstall rate: Low numbers mean more opportunities for ongoing revenue, high figures mean you’re a low-value app for the store.
  • Engagement: Engaged users are more likely to spend money, more often.
  • In-app purchases: Money in the bank.
  • Updates: Bug fixes, new features and reasons for people to keep using apps and spending money.

Perform well in these areas and you’re going to rank well in app stores. In this sense, app store optimisation is more straightforward than SEO because the more revenue you generate through your app, the more stores make in return and stronger your presence becomes in the app store.

Need help with app store optimisation?

If you need to increase the visibility of your app in the App Store or Google Play, find out about our app store optimisation services or contact our mobile specialists on 02392 830281 or [email protected].

Dave Colgate profile picture
Dave Colgate

Dave is head of SEO at Vertical Leap. He joined in 2010 as an SEO specialist and prior to that worked with international companies delivering successful search marketing campaigns. Dave works with many of our largest customers spanning many household names and global brands such as P&O Cruises and Harvester. Outside of work, Dave previously spent many years providing charity work as a Sergeant under the Royal Air Force Reserves in the Air Cadets sharing his passion for aviation with young minds. He can often be found in the skies above the south coast enjoying his private pilot licence.

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