How Do ASO Tools Actually Work?

July, 13 2017

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Patrik Winkler
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Patrik Winkler

You've probably read a lot about how important App Store Optimization is for your app marketing efforts.

You might even have read posts about ASO strategy on this blog.

Consider this your no-nonsense primer on ASO tools.

You’ve heard a lot about why App Store Optimization is so important. But how does it all work? What quantifiable data is available for you to make strategic and tactical ASO decisions? You want to get your app in front of the people who are within your target group - how do all those ASO tools out there help you do that?

There are 3 ways for you to get your app in front of a user’s eye within the app stores.

  1. Being featured
  2. Ranking in the top charts
  3. Being found via app store searches

Especially when starting out there is a high chance that the main way your target users find you is via c) - they find you when searching the app stores.

Just as websites can generate more organic hits through SEO, apps can become more popular with ASO. ASO can be further split into Keyword Optimization and Creative ASO.

Keyword Optimization is helping you get discovered and more traffic to your app page in the app stores. Creative ASO helps you convert users once being on your app page.

For this post, we will focus on Keyword Optimization.

How does it all work?

A user searches for a search term in the app store and finds some results for the specific search. You want to make sure you are using the right keywords for your target group, so you appear when they are searching for something you think you can solve best.

Apple App Store

For Apple, your toolkit is pretty straight forward, the following things play into if you are ranking for a search or not:

  • App name, 50 characters (counts the most, so put keywords here, if not focused on brand)
  • iTunes connect keyword field, 100 characters (words split via [comma], preferable use single keywords)
  • App publisher name
  • In-app purchases
Google Play Store

Here, the game is a bit different:

  • App name, 50 characters (put most important keywords here)
  • App description (repeat keywords 3-4x, +/- 10 keywords in the description, keyword phrases preferable)
  • App publisher name

The main difference between those two is that Google is a bit more secretive about what plays into it and how you need to work out your description. Additionally, for Google it seems that retention of an app and ratings & reviews play a role for the algorithm as well.

Generally, keep in mind that the individual app stores have a vested interest to show the user of their app store a result which satisfies them. Meaning, if users who search for “writing app” always end up downloading Evernote, based on the conversions of Evernote for the keyword “writing app”, Evernote will rank higher than apps that convert less for the keyword. Darwin’s law, kinda.

So, how do you decide which keywords you want to rank for?

There are four dimensions you need to understand to work that out: search popularity, competition, relevancy, and rank. Let’s take a look at each of those in detail.

1. Search Popularity

What is it?

Search Popularity (as Apple calls it) is the amount of search volume a keyword generates, so how much traffic it gets compared to others.

Why is it important?

When picking a keyword, it is up for you to decide how important it is, if there is a lot of traffic to it. My guess is, however, that you wouldn’t mind having the chance to get more people to download your app.

How do you measure it?

With the introduction of Search Ads, Apple started providing the actual Search Popularity of every keyword for English speaking countries. This index is ranging from 5-100. So, you don’t get the exact amount of traffic which makes it tough for the tracking nerds of you, but what you still can find out is a volume comparison. Keyword A has a Search Popularity of 56 vs Keyword B has a Search Popularity of 75.

This number is provided for English speaking countries by Apple and calculated on proprietary sources by ASO tools.

In the Google Play Store, the game is a bit different. Google, having started out as a search engine, has played this game for a while and offers an index for mobile search volume which provides you with an actual search volume. This search volume however is based on search queries from Google Search and Google Play. This means that search queries from iOS devices also count into that. Moreover, this index is a global number which we then allocated to specific countries based on our estimated country download shares.

While some other argue if this number is therefore inflated, it still shows search volume and interest of users for a keyword & the behavior of users which you can leverage to pick a keyword based on comparison search volume. For simplicity reasons, we transfer this number into the same index as Apple, so Search Popularity, 5-100.

2. Competition

What is it?

A keyword doesn’t exist in a vacuum. Who says that just by picking a keyword you will rank for it? Even though Apple gives you a 7 days boost when you start using a keyword, you still need to know how difficult it is to rank for that keyword.

Why is it important?

Let’s take a look at a search result:

aso tools

As you can see, the space is quite limited. Within the top charts one says you will increase organic downloads when ranking in the top 20. For Keyword Optimization and search results experts say you need to be in the top 10, and sometimes even in the top 3-5 to see any effect.

With the introduction of Search Ads the space is even more limited.

How do you measure it?

ASO tools have different approaches to give you an indication for competition. Either they show you the likelihood of ranking in the top 10, or how how difficult it is for you to rank in the top 10.

I can’t confirm what others are using to calculate this metric. Here at Priori Data we look at two factors.

  1. The size of the apps ranking for the keyword - if Facebook and Instagram are on top, you will have a hard time kicking them off from there.
  2. The fluctuation of the apps in the top 10 - if we see that the apps ranking in the top 10 change often, there is no established player yet for that keyword.

You will have a fair chance of collecting installs from that keyword (again depending on how much traffic is coming to the keyword).

The Competition Score is ranked from 1-100. 1 equals really low competition and 100 means very high competition.

3. Relevancy

What is it?

Ok, so now you have the popularity for a keyword and how competitive a keyword is. This is already a great way for picking keywords. But the crucial part is that you rank for keywords that will actually convert to installs. And not only installs, but hopefully engaged users over time.

To achieve this, you need to find out, how your target group is searching for you / how they describe your app.

Why is it important?

Google says that over 50% of searches are branded searches. That means, that half of the searches are basically shortcuts to download an apps. The other 50% are users scanning through and exploring what apps are there for a specific topic. Let’s say you have a note taking app. You might choose to rank for “writing app” because of high traffic and ok competition score, but it likely makes more sense to go for a bit less traffic and pick “note taking”. (You never need to have “app” as a keyword, just like “free” or others.) Through that keyword you should have fairly more qualified traffic than via “writing” as a keyword.

3. Relevancy writing.pngaso tools

How do you measure it?

However, how relevant a keyword is, is a bit of magic, a bit of creativity on your side, and a bit of blackbox algorithm by the app stores. Considering that no one except you (and hopefully your users) know what exactly you do, it is hard to give you an index for how relevant a keyword is for you.

What you can do though is to look at what keywords are most used within your category, or what keywords your competitors are using and how many of your direct competitors are using it.

app store optimization keyword volume estimator4. Rank

What is it?

Search Popularity, Competition Score, and relevancy, they all lead to one thing - ideally - you ranking high for a keyword. Track your keyword ranking via an ASO tool to see how you are ranking over time and if anything changes.

Why is it important?

Some tools provide you with a list of all keywords you are already ranking for (and your competitors), so you know where you currently stand. With that knowledge and knowing which keywords you are currently using, you can evaluate which keywords to drop and which keywords to keep, because you are ranking high and the search volume is what you desire to have.

app store optimization keyword volume estimatorHow do you measure it?

A rank is a fixed number without any estimates and directly pulled from the App Stores. So depending on what position you have for any keyword, this will be the position shown in the ASO tool.

Keyword Optimization naturally comes with a lot of experimentation. So, when you try a new keyword, you want to see how high you rank for it and if you want to keep the keyword. There are also cases, where you realize you are ranking for a keyword that you don’t even use yet. Exchanging another one and bringing that one in, will likely help you rank even higher for it.

Additionally, as it just happened, the app stores are constantly improving their search algorithms. Hence, your ranking for a keyword might suddenly change. Because of that you want to keep a close eye on the keywords you are currently ranking for to spot any developments, positively or negatively.


There is far too much mystery in ASO. Nobody likes to unpack the data in public - probably because so much of it is tied up in Google and Apple's black box algorithms.

We wanted to take the mystery out, as much as possible. If you still have questions after reading this - get in touch with me on Twitter.

The Ultimate Guide to 360° App Store Marketing

This article is part of a bigger project with Priori Data and Peggy Salz — a mobile authority, industry educator and lead author of The Everything Guide To Mobile Apps and Apponomics: The Insider’s Guide To A Billion Dollar Business— are working on: an e-book titled THE ULTIMATE GUIDE TO 360° APP STORE MARKETING.

The aim is to bring together a select group of recognized ASO experts and ninjas including Moritz Daan (Phiture, ex-Soundcloud), Thomas Petit (8Fit) and Charo Paredez Ortiz (DOCOMO Digital), to name a few. It’s a free resource focused on giving app developers everywhere on the planet what they need to grow their business on a budget.

Pre-register for the e-book today

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