How to use the App Store keyword field (all 100 characters of it)

The keyword field is 100 bytes of text that App Store users never see. It exists for one reason: to tell Apple's search engine which terms your app is relevant for, beyond what fits in your name and subtitle. Most apps waste a fifth of it on spaces, duplicates and words that do nothing.

This guide covers the format Apple expects, the rules that save bytes, how words in different fields combine, and how to iterate once you're live. If you're new to ASO, start with the complete ASO guide first.

How the keyword field works

In App Store Connect, the keyword field sits on each version's page, per localization. Apple's reference describes it as one or more keywords, each longer than two characters, up to 100 bytes in total. Three details matter more than they look:

• It's bytes, not characters. Plain English letters take one byte each, so 100 bytes is 100 characters. Accented letters such as ü or é take two bytes, and Chinese, Japanese or Korean characters usually take three. A German or Japanese keyword field holds fewer characters than an English one.
• It's per localization. Every language you add in App Store Connect has its own keyword field.
• It only changes with a new version. Unlike promotional text, you can't edit keywords on a live version. Plan changes around your release cadence.

The format: commas, no spaces

Apple's search guidance says keywords are separated by commas with no spaces between them. Spaces inside a phrase are fine; spaces around commas are just wasted bytes.

Nine bytes is enough for one more word, such as thunder or tinnitus. Across 10 languages, that's 10 to 20 extra chances to be found.

How words combine across fields

Apple treats your app name, subtitle and keyword field as one pool of searchable text. You don't need to repeat a word in the keyword field if it's already in the name or subtitle, and Apple's guidance explicitly says not to.

In practice, many developers also observe that words from different fields can match multi-word searches together. If "sleep" is in your name and "sounds" is in your keyword field, you can still be relevant for "sleep sounds". Apple doesn't document exactly how combinations are scored, so treat this as a strong tendency, not a promise. Exact phrases in the name or subtitle generally remain the most reliable way to rank for a phrase.

This is also why you rarely need to write full phrases in the keyword field. Writing rain sounds,ocean sounds,fan sounds spends bytes on "sounds" three times. If "sounds" already sits in your name, rain,ocean,fan does the same job for a fraction of the space.

When to keep a phrase intact

Keep a multi-word phrase together when the words only make sense as a unit or when splitting would create misleading matches. Brand-like terms, compound concepts such as white noise, and phrases where word order matters to searchers are good candidates. For everything else, single words give you more combinations per byte.

Eight rules that save bytes

Most of these come straight from Apple's search guidance and the App Review Guidelines. The rest are simple byte arithmetic.

1. No spaces after commasCommas separate terms; spaces around them cost bytes and add nothing.
2. Pick singular or plural, not bothApple says plural and singular forms such as "climb" and "climbs" are considered duplicates. Keep the shorter one unless the longer one reads more naturally in searches.
3. Don't repeat words from your name or subtitleThey're already indexed. Repeating them in the keyword field is pure waste.
4. Don't repeat your category nameApple advises against repeating words from your category. If you're in Health & Fitness, "fitness" doesn't need a slot.
5. Drop "app", "game" and filler wordsApple calls out generic terms like "app" and "game" and filler such as "the" or "to". People still find you without them.
6. Skip your company nameYour app is already searchable by its developer name, per Apple's reference.
7. No competitor names or trademarksNames of other apps or companies aren't allowed in keywords. Guideline 2.3.7 also rules out unauthorized trademarks and celebrity names.
8. Only words that describe your appIrrelevant or misleading terms break guideline 2.3.7 and, even if they slip through, bring visitors who won't download.

Before and after: a real-world cleanup

Here's a typical keyword field for a fictional sleep sounds app named Driftly: Sleep Sounds with the subtitle White noise & rain, in the Health & Fitness category. Wasted words are struck through.

Notice the "after" version contains words like brown and pink that look odd on their own. They only make sense because "noise" is in the subtitle. That's the field-combination principle doing its work.

Choosing which keywords earn a slot

Once the format is clean, the real question is which words deserve the space. Three things matter for every candidate:

• Relevance. Would someone typing this term be happy to find your app? If not, skip it, whatever its volume.
• Search volume. How often people search the term. A perfect match for a term nobody types won't bring downloads.
• Competition. How strong the apps already ranking are. Top results held by apps with huge rating counts are hard to break into for a new app.

A simple way to fill the field: put your one or two most valuable phrases in the name and subtitle, then fill the keyword field with sweet-spot and quick-win words that combine well with them. Leave the hardest terms for later, once you have downloads and ratings behind you.

A step-by-step way to fill the field

1. Start from your full candidate listCollect every relevant term from your research: what the app does, the problems it solves, who it's for and the features people search for by name.
2. Remove what's already coveredStrike out every word already in your name, subtitle or category, plus generic words like "app", and your company name.
3. Break phrases into wordsTurn "rain sounds" and "ocean sounds" into "rain" and "ocean" when "sounds" is already indexed elsewhere. Keep true compounds together.
4. Collapse duplicatesKeep one form of each word: singular or plural, not both. Drop near-synonyms that add little.
5. Rank what's leftOrder the remaining words by relevance first, then search volume, then how winnable they are. Fill the field from the top until you hit 100 bytes.
6. Read it once moreCheck that every word would make sense to someone who finds your app through it. If not, swap it for the next word on your list.

Tools that show search volume and the strength of the apps ranking for each term make this much faster than guessing. In Appsium, keyword research shows a Volume score and App Store competition side by side, and highlights which words are already in your title, subtitle or keyword field. No tool can guarantee a ranking, but good data helps you spend 100 bytes on the right words.

Keywords in other languages

Every localization has its own 100 bytes, and that's one of the cheapest ways to expand your reach. A few things to keep in mind:

• Research terms locally. Direct translations often miss what people actually search for in that market.
• Count bytes, not characters. The Japanese term above is 7 characters but 21 bytes in UTF-8.
• Follow the same rules. No repeats of the localized name and subtitle, no competitor names, no filler.

The localization guide covers choosing markets and adapting your whole page.

Iterating after launch

Your first keyword field is a hypothesis. Here's a loop that turns it into knowledge without guesswork:

• Write down your current keyword field and the date it went live
• Track where you rank for each important term, once a week
• After a few weeks, flag words where you rank nowhere and words that bring impressions but no downloads
• Replace three to five of the weakest words in your next version, not the whole field
• Promote a keyword-field word to the subtitle if it performs well and deserves more weight
• Check App Analytics for impressions and downloads from App Store Search, not just rankings
• Repeat with every release

Next, make sure the two most visible fields pull their weight: read how to write your title and subtitle.

Frequently asked questions