App Store Keywords: The 100-Character Field, Explained
How the App Store keyword field works, what to put in 100 characters, what to leave out, and how it differs from the title and subtitle.
The **App Store keyword field** is a 100-character box in App Store Connect, and it is the most misunderstood part of iOS ASO. It is not a place to repeat the title, and it is not a place to write sentences. It is a compact list of terms the App Store can index alongside your title and subtitle.
Here is how to use it without wasting characters or tripping over the rules.
Key takeaways
- The field allows up to 100 characters, including commas.
- Do not repeat words already in the title or subtitle; the store already indexes them.
- Spaces after commas are allowed but waste budget.
- Use singular forms and avoid duplicates; the store handles common variants.
- Never include competitor brand names or irrelevant terms.
What the keyword field is for
Apple indexes the title, subtitle, and keyword field for search. The keyword field exists so you can cover terms that do not fit naturally into the visible name or subtitle. It is invisible to users, which makes it tempting to dump everything into it. That is a mistake: irrelevant terms can attract the wrong impressions, and repeated terms waste scarce space.
| Field | Limit | Visible to users? |
|---|---|---|
| App name / title | 30 characters | Yes |
| Subtitle | 30 characters | Yes |
| Keyword field | 100 characters | No |
| Description | 4,000 characters | Yes |
Limits are current at the time of writing. Confirm them in App Store Connect before submitting, especially if you are managing multiple locales.
The no-repeat rule
If your title is `Blood Pressure Log` and your subtitle is `Track BP and glucose`, do not put `blood pressure log track bp glucose` in the keyword field. Those words are already indexed. Use the field for new phrases: `hypertension diary, pulse record, health journal`. Each comma-separated term can be a word or a phrase.
Apple combines words across fields when matching a query, so a phrase does not need to appear verbatim in one field. That is why single words can be more efficient than full phrases in this box, as long as the words are specific.
What to put in 100 characters
- List the phrases you scored as Primary but could not fit in the title or subtitle.
- Remove any word already present in the title or subtitle.
- Remove duplicates, plurals, and near-identical variants.
- Remove competitor names, trademarks, and unrelated high-traffic terms.
- Separate terms with commas; skip spaces after commas to save characters.
- Check the counter in App Store Connect, not a word processor.
A filled field might look like `hypertension diary,pulse record,health journal,bp tracker,pressure monitor`. Notice that `blood pressure` is absent because it is already in the title. This is not a volume play; it is coverage.
Singular, plural, and stemming
Apple's matching is not a simple exact-string lookup. It can handle common variants, so `tracker` and `trackers` usually do not both need a slot. Use the form a person is most likely to type, then spend the saved characters on a different concept.
Localisation changes the field
Each locale has its own keyword field. Do not paste the English list into every language. Translate the intent, not the characters, and have a native speaker check it. A term that is common in English may be unnatural or ambiguous in another market. NewASO's Localization screen keeps per-locale budgets, but the linguistic judgement still belongs to a human.
Common mistakes
- Pasting the same list into every locale.
- Adding a competitor's app name.
- Using the field for sentence-like copy.
- Repeating the title to 'reinforce' it.
- Filling all 100 characters with low-relevance terms just because space exists.
How this fits the rest of the listing
The keyword field cannot rescue a vague title or a weak first screenshot. Use it after you have chosen the phrases that matter, not as a substitute for positioning. If you are still deciding which phrases deserve the title, start with app keyword research. For Google's very different field rules, read Google Play keywords.
Frequently asked questions
How many characters does the App Store keyword field allow?
Up to 100 characters, including commas. Spaces after commas are allowed but consume the same budget, so many developers omit them.
Should I repeat title keywords in the keyword field?
No. Apple already indexes the title and subtitle. Repeating them wastes characters that could cover a new phrase or concept.
Can I use competitor names as keywords?
No. It risks trademark issues and review problems, and it is not a legitimate long-term strategy. Compete on the job to be done, not on another company's name.