Reference

App Store Optimization

What the two stores read, what they ignore, and which of it you can change.

App Store Optimization is the work of being found in a store's own search. Most installs on both stores start with somebody typing something — not with an ad, and not with a feature. ASO is what decides whether you are one of the results.

It is a smaller subject than it is usually made to sound. Three things decide a ranking, and only the first is fully yours.

1. What you are indexed for

A store can only rank you for words it has read somewhere in your listing. This is the part you control completely, and it is where most of the available gain sits — an app that never writes down "sleep timer" cannot rank for it, however good it is at timing sleep.

The two stores read different fields, which is the single most important practical difference between them:

• The App Store indexes your app name, your subtitle and a hidden 100-character keyword field. It does not index your description. Words written there are read by people and by nothing else.
• Google Play indexes your title, your short description and your full description — all 4000 characters of it. The body copy is both the thing a person reads before installing and a ranking surface.

That difference changes what you write. On Apple, every indexed character is scarce and duplication is waste. On Play, the body has room, and the question becomes which terms it should carry and how often. The two are covered field by field in App Store metadata and Google Play metadata.

2. How hard those words are to take

Being indexed for a keyword is not the same as ranking for it. Every term already has ten apps above the fold, and displacing them is a function of who they are: how many ratings they carry, how well their own metadata matches the term, how entrenched they are.

This is why "pick high-volume keywords" is bad advice on its own. A term searched by everyone and held by Instagram is worth less to you than a term searched by fewer people and held by nobody in particular. What matters is the demand you could realistically win, which is popularity discounted by difficulty — see choosing keywords you can rank for.

3. What happens after the impression

Both stores watch what people do with your result. An app that is shown often and installed rarely is telling the store something, and the store listens. Your icon, your screenshots, your rating and your first screenshot's caption are not indexed for search, and they still change your ranking, because they change your conversion rate.

This is the part that ASO advice tends to skip, because it cannot be edited in a text field. It is also the reason a keyword you rank for badly can be worth less than one you rank for well: position and relevance compound.

What you cannot do

A short list, because most of the time lost to ASO is lost here:

• Repeating a keyword does not help on the App Store. Apple counts a word once across your name, subtitle and keyword field. A word in two places has bought one place's worth of ranking and spent two places' worth of characters.
• Stuffing does not help on Play. The description is indexed, but a phrase repeated past the point of reading naturally is discounted — and it costs installs from the people who do read it, which feeds straight back into point 3.
• Competitor brand names are a trap. They are searched heavily, they are almost impossible to outrank, and the intent behind them belongs to somebody else. Apple also rejects them.
• Nothing works instantly. Both stores re-index on their own schedule after a release. A metadata change is measured in days, which is why measuring at all requires recording where you started.

What a working process looks like

1. Find the field. Start from one term you know is yours and expand it through what the stores themselves suggest. Store autocomplete is real demand, revealed by the store, for free.
2. Score it. For each term: how much it is searched, how hard the top ten are, and what is left over. Keep the ones where the third number is not zero.
3. Write the listing around what you kept. Not around what sounds good — the keywords you decided to chase, placed in the fields that store indexes.
4. Measure on the days you measured. Record your rank for those terms and watch them, so the next release is a comparison rather than a hope.

That loop is what this tool is: find the terms, keep the ones worth watching, write the listing that covers them, and read the ranks on the days they were taken.