Reference
Choosing keywords you can rank for
Three numbers decide whether a keyword is worth a slot. Here is what each one is.
Every keyword decision comes down to three numbers: how many people search it, how hard the apps above you are to displace, and what is left of the first once you account for the second. Everything else is detail.
Popularity — how much is searched
The demand behind a term. Apple publishes a search-popularity figure through its Search Ads API, which is the only first-party number either store gives out; Google publishes nothing comparable, because Keyword Planner measures web search and not the Play store.
Where a store does not publish it, popularity has to be estimated — and the honest estimate comes from the store's own autocomplete. A term the store suggests after two typed characters is in more demand than one it only offers once you have typed the whole phrase. It is an inference, and any tool showing you a popularity number for Google Play is showing you an inference. The useful question to ask of any ASO tool is whether it tells you which of its numbers are measured and which are modelled.
Difficulty — how hard the top ten are
Popularity on its own is a trap. "photo editor" is searched constantly and held by apps with millions of ratings; you will not be on that page, and being indexed for it changes nothing.
Difficulty is a property of the apps currently ranking, so it can only be computed by looking at them: how many ratings they carry, how well their own metadata matches the term, how entrenched the leaders are. A term where the top ten are ten strangers with four hundred ratings each is a different proposition from one where the top three are Calm, Headspace and BetterSleep, even if both are searched the same amount.
This is also why difficulty is not a fixed property of a keyword. It changes when the apps above you change.
Opportunity — what is left for you
Popularity discounted by difficulty: the share of the demand you could realistically win. It is the number to sort by, because it is the only one that answers the question you are actually asking — is this term worth one of my characters.
A term with popularity 70 and difficulty 80 can be worth less than one with popularity 45 and difficulty 20. The first is a bigger room you will not get into; the second is a smaller room with an open door.
Reading a keyword in practice
| Shape | What it usually means |
|---|---|
| High popularity, high difficulty | A head term. Worth tracking to see whether you ever move, rarely worth a title slot early on. |
| Moderate popularity, low difficulty | The keywords worth having. Not glamorous, and where most real ranking comes from. |
| Low popularity, low difficulty | Long tail. Individually small, collectively significant, and cheap to cover in body copy on Play. |
| Any popularity, and it is a brand | Somebody else's name. Hard to rank, the intent is theirs, and Apple rejects competitor names outright. |
| You already rank 1–10 | Defend it. Terms you hold are worth more than terms you might get, and they are the ones a listing rewrite can quietly lose. |
Where to find candidates
- Your own listing. Your title, subtitle and category are what the store already associates with you. Expanding those through autocomplete finds the field you are nearest to ranking in.
- Store autocomplete. Real demand, revealed by the store, free. Typing your seed term plus each letter of the alphabet turns one term into most of a category.
- Competitor listings. Not their brand — the generic terms they rank for that you have not written down. An app you compete with is a list of keywords somebody has already validated.
- What you already rank for. The cheapest keywords to improve are ones you are on page two of. The store already thinks you are relevant; you are asking it to think so slightly harder.
How many to keep
Fewer than the tools will offer you. The App Store gives you 160 indexed characters in total, which is perhaps 25 to 35 useful words; Play gives you more room in the body but every term you name is a term the copy has to carry naturally. A list of 500 keywords is a research artifact, not a plan.
Keep the ones you would be willing to write into the listing, plus the ones you already rank for and want to watch. That is usually somewhere between twenty and fifty.
Then measure
A keyword list is only worth having if you know where you stand on it. Rank is a reading taken on a day: run the search, find your app, write down the position and the date. Do that regularly and a listing change becomes a comparison instead of a hope — and you find out which of your metadata decisions actually moved anything.
The fields those keywords have to go into are covered in App Store metadata and Google Play metadata. The wider picture is in App Store Optimization.