Quick ASOThe short answer
The keyword field is a private list of search terms you enter in App Store Connect for each localization. Apple allows 100 characters (App Store Connect counts 100 bytes), terms separated by commas with no spaces, and no words you already use in your app name, subtitle or category.
What is the App Store keyword field?
The keyword field is a list of search terms you enter in App Store Connect, in the version information of each localization. Customers never see it, which makes it the place for words that describe your app but would read badly in a name or a subtitle.
Apple names four text inputs for search relevance: the app name, the subtitle, the keywords and the primary category. The keyword field is the only one of the four that customers cannot see, and the one with the most room: 100 characters, against 30 each for the name and the subtitle.
What are the keyword field rules?
Apple's documentation sets out these rules. Anything in the table comes from Apple's pages listed under Sources.
| Rule | What to know |
|---|---|
| Length | Up to 100 bytes in App Store Connect; Apple's search guide says 100 characters. Plain English letters and commas take one byte each. Accented letters and many other scripts can take more, so you fit fewer characters. |
| Separators | Commas, with no spaces. Apple's own example is Property,House,Real Estate. |
| Minimum | Apple's help describes each keyword as longer than two characters. |
| Words you already use | Don't repeat words from your app name, subtitle or category. Your company name is searchable too, so it doesn't belong here either. |
| Other brands | Names of other apps or companies aren't allowed. |
| Languages | Each localization has its own keyword field. |
What should go in the keyword field?
Words that describe what your app does, that people type into search, and that are not already in your name, subtitle or category. Work through it in this order:
- List the phrases you want to rank for. Take them from autocomplete, from competitors' names and from your own reviews. The keyword research guide shows how.
- Strike out the words you already use. Whatever is in your name, subtitle or category is already searchable, so repeating it spends characters for nothing.
- Split what is left into single words. ASO practitioners consistently find that Apple matches a search against words from different fields together, so "photo" in the name and "vault" in the keyword field can both count toward "photo vault". Apple does not publish this, so treat it as practice rather than a rule.
- Rank the words by demand and difficulty. A word that appears in several good phrases, and in none you cannot win, goes first.
- Pack the best into 100 characters. Each word costs its length plus one comma. The set with the most total value is not always the first words on the list or the shortest ones, so it is worth working out properly.
Quick ASO does the last step exactly: Suggest from your phrases, in the metadata editor on the Keywords page, picks the combination of words with the most total demand that fits in 100 characters.
What does a filled keyword field look like?
Here is a made-up app, Snapvault, a private photo vault. The numbers are counted from the text shown.
| Field | Text | Length |
|---|---|---|
| Name | Snapvault: Private Photo Vault | 30 of 30 |
| Subtitle | Hide Videos, Notes & Files | 26 of 30 |
| Keyword field | secret, | 84 of 100 |
The name and subtitle already contain private, photo, vault, hide, videos, notes and files, so none of those appear in the keyword field. Every word in it is new, there are no spaces after the commas, and no word is repeated.
What wastes keyword field characters?
- Spaces after commas. Every space is a character you could have spent on a word.
- Words from your name or subtitle. Apple already searches them.
- Singular and plural pairs. ASO practitioners report that Apple treats "photo" and "photos" alike, so listing both buys nothing. Apple does not state this.
- Competitor and trademarked names. Apple's help says names of other apps or companies aren't allowed, and App Review guideline 2.3.7 warns against packing metadata with trademarked terms or popular app names.
- Words that don't describe your app. The same guideline asks for keywords that accurately describe the app, and says Apple may modify inappropriate keywords at any time.
- Never looking at it again. The phrases people type change, so review the field with every release.
How do you know the keywords worked?
Record your rank for each target phrase before you submit the update, then check again once the new version is live. Change one field at a time where you can, so you know which edit moved a rank. Rankings can take days to a few weeks to settle, so compare over weeks rather than hours.
Quick ASO records the rank of every starred phrase each day, so the before-and-after is already on the chart when the update goes live.
Frequently asked questions
How many characters is the App Store keyword field?
Do I put a space after each comma in the keyword field?
Should I repeat words from my app name and subtitle in the keyword field?
Can I use a competitor's name as a keyword?
Can I change my keywords after my app is released?
Sources
What this guide says about Apple comes from these pages, which Apple can change. Statements marked as practice come from ASO testing, not from Apple.
See where your own app stands
Quick ASO lists every phrase your app ranks for, scores each one and tells you what to change. It is free to look. Open the app →