What the term means
Apple Search Optimization is App Store Optimization applied specifically to the iOS App Store: the work of getting your app to appear when someone searches the store for what it does. Most people use it interchangeably with ASO. The reason the Apple-specific phrasing exists at all is that the two big stores work differently enough that advice for one is actively wrong for the other.
It matters more than most developers expect. Store search is where a large share of app discovery begins, and unlike advertising it does not stop working when you stop paying. It is also the part of shipping an app that engineers are least prepared for, because none of the skills transfer from building the thing.
The one difference to internalise: Google Play indexes your long description, so keyword-rich copy helps there. Apple does not. On iOS your searchable surface is the app name, the subtitle, a hidden 100-character keyword field, your developer name, your in-app purchase names and your category. That is the whole of it.
What Apple actually indexes
| Field | Budget | How to use it |
|---|---|---|
| App name | 30 characters | The heaviest weighted field. Brand plus your single strongest phrase. Most apps waste it on brand alone. |
| Subtitle | 30 characters | Weighted close behind the name, and visible to users, so it has to read as a sentence rather than a keyword list. |
| Keyword field | 100 characters | Never shown to users. Single words, comma separated, no spaces after commas, nothing repeated from the name or subtitle. |
| In-app purchase names | Per item | Indexed, and routinely forgotten. Name them descriptively rather than “Pro Plan”. |
| Developer name | Account level | Indexed. Occasionally worth a keyword if you are setting up a new account. |
| Description | 4,000 characters | Not indexed. Write it for conversion, not for search. |
Two mechanical rules follow from this and are worth committing to memory. First, Apple combines words across all indexed fields to build phrases, so you do not need to write phrases yourself — if “quit”, “vaping” and “tracker” each appear once anywhere in your metadata, you are eligible for the combinations. Second, and following directly from that, repetition is pure waste. Every duplicated word is a word you did not cover.
Also skip articles and connectors, do not include your own category name if it is already implied, and do not use competitor brand names — that is a rejection risk with no upside.
How ranking actually works
Apple does not publish its algorithm, and anyone claiming a precise formula is selling something. But the observable behaviour across thousands of result pages is consistent enough to work from, and it splits into two stages.
Stage one: are you eligible?
Relevance decides whether you appear for a phrase at all. This is almost entirely a metadata question — do your indexed fields contain the words, and does your app genuinely relate to them. This stage is fully within your control, and it is what keyword research is for.
Stage two: where do you land?
Among the apps that are eligible, position is heavily influenced by popularity signals you cannot edit: installs, ratings volume, rating quality, engagement and retention. This is why the same metadata produces wildly different outcomes for a new app and an established one.
The practical consequence is the thing most guides skip. Perfect metadata makes you eligiblefor a phrase; it does not make you visible for one. On a page where the top ten all have tens of thousands of ratings, being eligible puts you at position 60. This is why whether a new app can rank is a different question from how difficult a keyword is, and why choosing launch keywords is a fundamentally different exercise from choosing keywords for an app that already has users.
Spending your metadata budget
You have roughly 160 characters, or about 20 to 25 distinct indexed words per localization. Treat it like a budget and allocate deliberately:
- The name carries your single best phrase. The one term you most want to own, that you have a real chance at. “Brand — Quit Vaping Tracker” beats “Brand” for every app that is not already famous.
- The subtitle carries the next cluster, written as something a human would read. It is on your product page and it affects whether people tap, so it cannot be a keyword dump.
- The keyword field carries everything else as single words. Synonyms, the words people use that you would not, misspellings that are genuinely common, and the modifiers that form long tails with words already in your title.
- Localizations multiply the budget. Each localization has its own fields. Adding a localization for a market you already sell in gives you a fresh 160 characters for that storefront — one of the highest-leverage moves available, and widely ignored.
Myths worth dropping
- “Put keywords in the description.” Not indexed on iOS. This advice is imported from Google Play or the web and it wastes your best conversion asset.
- “Target high-volume keywords.” Volume you cannot rank for is worth precisely nothing. A phrase with modest demand you reach position 4 for beats a huge one where you sit at 80.
- “Low competition means opportunity.” Sometimes it means nobody searches it. The useful version of this signal is narrower: people search it, and the apps ranking are answering a different question. That gap is an opening; emptiness usually is not.
- “Use plurals and variations to be safe.” Apple handles most pluralization on its own. Spending characters on both “tracker” and “trackers” usually buys nothing.
- “Set it once at launch.” Result pages move, competitors change their metadata, and the terms you can win widen as you accumulate ratings. Metadata is something you revise every few releases, against evidence.
What to actually do at launch
- Build a candidate list from Apple’s own autocomplete rather than your imagination — it is the closest thing to free demand data the store publishes.
- For each candidate, look at who ranks and how strong they are, and specifically at how many of the top ten are small enough that a newcomer could displace them.
- Choose launch terms you can win now, not the ones you want. Write the head terms down as a destination for later rather than spending metadata on them today.
- Allocate the name, subtitle and keyword field with nothing repeated, then localize for every market you sell in.
- Capture your positions on a schedule from day one, so that when you revise the metadata you can tell whether anything actually changed.
The keyword research guide covers steps one and two in detail, including a method you can run by hand. If you would rather it were done for you, that is what GetRevuu is.