The iOS App Store gives you exactly 100 hidden characters that most developers half-waste. The keyword field is Apple's single most misunderstood ranking surface — invisible to users, strict about formatting, and unforgiving of duplication. Get it right and you index for dozens of terms; get it wrong and you burn a third of your ranking inventory on words that do nothing. This guide covers every rule, in order of impact.
It's a focused deep-dive that pairs with our full keyword research guide and the complete character limits reference.
What Is the iOS App Store Keywords Field?
The keywords field is a hidden, 100-character metadata field in App Store Connect where you list search terms you want your app to rank for. Unlike the title and subtitle, users never see it — it exists purely to feed Apple's search index. It's one of only three fields Apple indexes for iOS search, alongside the app name (30 characters) and subtitle (30 characters), giving you a total of just 160 indexed characters to work with.
How Do You Format the Keywords Field Correctly?
Formatting is where the easy wins and easy losses live. The rules, in order of how much they matter:
- Separate terms with commas, no spaces. Write
journal,diary,mood,tracker— notjournal, diary, mood, tracker. Every space after a comma is a wasted character that could have been another keyword letter. - Use single words, not phrases. Apple recombines individual keywords into multi-word searches automatically. List
habit,tracker,dailyand you rank for "habit tracker," "daily habit," and "daily tracker" — three phrases from three words. - No spaces means more keywords. A field written with ", " separators wastes one character per term; across a full field that's room for an entire extra keyword.
- Don't use the full 100 on long words. Prefer several short high-value terms over one long phrase that eats your budget.
What Should You Never Put in the Keywords Field?
Half of getting the keyword field right is knowing what to leave out. Every one of these wastes characters that add zero ranking value:
- Words already in your title or subtitle. Apple indexes those fields and combines them with your keywords automatically — repeating a title word in the keyword field is pure waste and adds no ranking benefit.
- Your app's category name. Apple indexes your primary category automatically. Listing "games" when you're in the Games category buys nothing.
- Plurals of words you already have. Apple's matching handles most singular/plural variants, so covering both "habit" and "habits" usually doubles the cost for a marginal gain.
- Spaces, and the word "app." Nearly every search that includes "app" still matches without it; spend those characters elsewhere.
- Competitor brand names and trademarks. Apple rejects trademarked terms and it can hold up your review.
How Do You Choose the Right Keywords to Include?
With duplicates and filler removed, the field is for net-new terms — synonyms and related concepts that don't appear anywhere else in your metadata. If your title says "meeting notes," your keyword field covers the ground the title can't: transcription,minutes,summary,recorder,voice.
Three sources fill the field efficiently:
- Synonyms of your title/subtitle terms — the words users type for the same concept you already lead with.
- Long-tail modifiers — specific qualifiers ("offline," "free," "pro") that Apple recombines with your other terms.
- Validated competitor keywords — terms multiple rivals rank for that you don't. Our guide on finding competitor keywords covers the extraction method.
How Is iOS Different From Google Play Keywords?
This trips up developers publishing to both stores. iOS has a dedicated, hidden 100-character keyword field; Google Play has no keyword field at all. Google reads keywords from your full description (up to 4,000 indexed characters) based on natural frequency and context. So the same keyword strategy inverts between stores: on iOS you list precise single words in a hidden field; on Google Play you weave those words naturally into readable description prose. Doing iOS-style comma lists in a Play description reads as spam to both the algorithm and the user.
Do You Localize the Keyword Field?
Yes — and it's one of the most underused ranking tricks on iOS. Apple lets you set a separate keyword field per localization, and it indexes keywords from certain other localizations for the same storefront too. The classic example: for the US App Store, adding the "English (UK)" or "Spanish (Mexico)" localization gives you a second and third 100-character keyword field that also apply to US search — effectively tripling your indexed keyword space without translating the app. Our localization prioritization guide covers which locales to add first.
How Do You Know If Your Keyword Field Is Working?
Set it, then measure. After Apple reindexes (usually a few days), check your rankings for every term you added — the ones you rank for are working, the ones you don't are candidates to swap out next cycle. The keyword field isn't set-and-forget: treat it as a rotating experiment where you replace non-ranking terms monthly. A free ASO audit scores your current keyword field usage, and rank tracking shows which terms actually moved.
Frequently Asked Questions
How many characters is the iOS keyword field?
Exactly 100 characters per localization. Combined with the 30-character app name and 30-character subtitle, Apple indexes just 160 characters total for iOS search — which is why wasting even one on a duplicate word hurts.
Should I use spaces after commas in the keyword field?
No. Write keywords comma-separated with no spaces (diary,journal,mood). Every space after a comma is a wasted character; across the full field, dropping spaces frees room for roughly one extra keyword.
Should I repeat my app title words in the keyword field?
Never. Apple already indexes your title and subtitle and combines those words with your keyword field automatically. Repeating a title word in the keyword field adds zero ranking value and wastes characters you could spend on new terms.
Does Google Play have a keyword field like iOS?
No. Google Play has no dedicated keyword field — it extracts keywords from your full 4,000-character description based on natural usage. iOS keyword strategy (precise single words in a hidden field) is the opposite of Google Play strategy (natural keyword-rich prose).
Can I rank for multi-word phrases with single keywords?
Yes. Apple automatically recombines your individual keywords into multi-word searches. Listing "habit,tracker,daily" ranks you for "habit tracker," "daily habit," and "daily tracker" — so list single words and let Apple build the phrases.
Key Takeaways
- The iOS keyword field is 100 hidden characters — one of only 3 indexed iOS fields (160 chars total).
- Comma-separate with no spaces; use single words and let Apple build phrases.
- Never include title/subtitle words, your category, plurals, or "app" — all zero-value.
- Fill it with net-new synonyms, long-tail modifiers, and validated competitor terms.
- Add extra localizations to multiply your indexed keyword space for free.
Filling 100 characters optimally across synonyms, competitor gaps, and multiple localizations is exactly the kind of constraint puzzle software solves faster than a spreadsheet. AppDrift's metadata generation builds a compliant, non-duplicating keyword field in seconds — and validates it before you submit.