App Store Keywords: How to Fill the 100-Character Keyword Field

In short: The App Store keyword field holds up to 100 bytes per localization, written as single words or short phrases separated by commas with no spaces. Apple indexes it together with your app name, subtitle, category and company name, so never repeat words from those, skip plurals of words you already use, and leave out competitor names. Put your most important term in the name, the next in the subtitle, and fill the keyword field with every other relevant word that fits.

The keyword field is the one piece of App Store metadata no customer ever sees, and it is easy to waste. This guide covers what Apple documents about it, as of October 2026, and a method to fill it that you can repeat every release.

How the keyword field works

These are the rules Apple states in App Store Connect help and its App Store search guidance:

• Up to 100 bytes per localization. App Store Connect help says "you can provide up to 100 bytes of content." Apple's marketing pages say "100 characters," which is the same thing only for plain ASCII text (more on that below).
• Commas, no spaces. "Terms separated by commas and no spaces. You can use spaces to separate words within keyword phrases. For example: Property,House,Real Estate."
• Each keyword longer than two characters. App Store Connect describes the field as "one or more keywords (each greater than two characters)."
• Don't duplicate your name or company name. "Your app is searchable by app name and company name, so you shouldn't duplicate these values in the keyword list."
• No other apps or companies. "Names of other apps or companies aren't allowed."
• Apple can edit it. Guideline 2.3.7 asks you to "assign keywords that accurately describe your app" and not to pack metadata "with trademarked terms, popular app names, pricing information, or other irrelevant phrases just to game the system." It adds that "Apple may modify inappropriate keywords at any time."

Two practical facts follow. The field is private: it is not shown on your product page, and competitors can only guess it from what you rank for. And it is saved with the version's localized metadata, so new keywords go live only when a new version is approved. Apple documents promotional text as the text you can change at any time, and states it "doesn't affect your app's search ranking."

Which fields Apple indexes

Apple's search page says results are based on "text relevance (matches for your app's title, subtitle, keywords, and primary category)" plus user behavior such as downloads, ratings and reviews. Here is every text field, with what Apple says about it:

The last row is often misread. Apple's page on promoting in-app purchases says promoted, non-consumable purchases and subscriptions can appear as their own results in search, leading to your product page. It does not say their names count toward how your app ranks. Treat them as extra shelf space, not as a second keyword field, and follow Apple's advice to give them specific names tied to your app rather than "100 gems."

Bytes, not characters: why your field fills up faster in some languages

App Store Connect counts bytes. Text is stored as UTF-8, where, per RFC 3629, a character takes 1 to 4 bytes depending on its code point:

Worked examples, counted with a UTF-8 encoder:

• habit,routine,goal is 18 characters and 18 bytes.
• alışkanlık (Turkish for "habit") is 10 characters but 13 bytes: two ı and one ş take 2 bytes each.
• alışkanlık,rutin,hedef,günlük is 29 characters and 34 bytes.
• 習慣,目標,日記 (habit, goal, journal in Japanese) is 8 characters and 20 bytes: six characters at 3 bytes plus two ASCII commas at 1 byte.

So a Japanese field holds at most 33 kanji or kana, fewer once you add commas.

Here is where it bites in practice. Suppose Streakly, the hypothetical habit tracker we use below, adds a Turkish localization with the name Streakly: Alışkanlık Takibi and the subtitle Günlük Rutin ve Hedef Planı. A translator hands over this keyword field:

hatırlatıcı,motivasyon,disiplin,sabah,odak,ruh hali,verimlilik,kontrol listesi,seri,ajanda,uyku,yoga

A character counter says exactly 100, so it looks full and valid. In bytes it is 103, because hatırlatıcı contains three dotless ı letters at 2 bytes each, and App Store Connect won't accept it. Dropping yoga brings it to 98 bytes. Two rules follow: always separate with the ASCII comma (1 byte), and never trust a character counter from a word processor. Count bytes.

What not to put in the field

Apple's search guidance lists what to avoid. Each item wastes bytes, risks rejection, or both:

• Words already in your app name, subtitle or category.
• "Plurals of words you've already included, such as 'climbs' and 'climb,' as these are considered duplicates."
• Generic terms "such as 'app' or 'game.'"
• Filler words "like 'the' and 'to.'"
• Special characters such as # or @, unless they are part of your brand.
• Competing app names, and "unauthorized use of trademarked terms, celebrity names, or other protected words."

How words combine across fields

Apple does not document how multi-word searches are matched. What follows are observations, ours and those widely reported by ASO practitioners, not Apple rules:

• Words appear to combine across the name, subtitle and keyword field. An app with "habit" in its name and "planner" in its keyword field often ranks for "habit planner." That is why single words usually beat long phrases: each word can pair with every other one.
• Word order inside the field doesn't seem to matter much; placement does. Words in the app name tend to carry more weight than words in the subtitle, and both more than the keyword field.
• Exact phrases still help for very competitive searches. If a two-word term is your main target, putting it together in the name or subtitle is the safer choice.

Test these on your own app: change one thing per release and watch the ranks.

Localizations give you extra keyword fields

Every localization you add has its own name, subtitle and 100-byte keyword field. Apple's localization reference shows that many storefronts support several languages; the United States, for example, lists English (US) plus Spanish (Mexico), Chinese, Korean and others. Practitioners have long observed that a storefront's search also reads some of these additional localizations, which effectively adds keyword space in the same country. Which pairs count, and how to use them without confusing local users, is covered in depth in our App Store localization guide.

A step-by-step method to fill the field

1. Collect candidates

List 50 to 100 terms: what your app does (features), what problem it solves (outcomes), who it is for, and the words users use in your own reviews and in competitors' reviews. Include synonyms and common misspellings only if people really type them. Our App Store keyword research guide explains where to find candidates.

2. Check popularity and difficulty

For each candidate you need two numbers: how often people search it and how hard it is to rank. Apple's own popularity score comes from Apple Ads; our guide to getting Apple's official popularity shows how to see it for every keyword you track. For a quick check of a single term, the free App Store keyword checker shows popularity (Apple's score when available, otherwise a labeled estimate), difficulty and the current top 10 apps in 50 countries, without an account.

3. Prioritize and place

Drop anything irrelevant, however popular: if users who search it don't want your app, the ranking won't convert. Then place the rest:

1. The single most valuable term goes in the app name, next to your brand.
2. The next two or three words go in the subtitle, written as a readable sentence for humans.
3. Everything else relevant goes in the keyword field, highest value first.

Two decision rules help when a word could go in more than one place. If a term is both your highest-volume search and a natural description of the app, it belongs in the name even if it makes the name less catchy. If a word only makes sense as part of a phrase ("self care", "to do"), test whether the single words already exist elsewhere in your metadata before spending bytes on the phrase.

4. Pack the field

Take the hypothetical habit tracker Streakly again, in its English (U.S.) localization.

• Name: Streakly: Habit Tracker (23 characters)
• Subtitle: Daily Routine & Goal Planner (28 characters)

A typical first draft of its keyword field:

habit tracker, daily habits, goals, routine planner, reminder app, self care, streak, journal

That is 93 bytes, but only four new terms remain once you remove waste: reminder, self care, streak, journal (33 bytes). The other 60 bytes go to seven spaces after commas, words already in the name or subtitle (habit, tracker, daily, routine, planner), plural duplicates (habits, goals) and the generic "app."

The packed version:

streak,reminder,checklist,journal,mood,discipline,productivity,motivation,morning,water,todo,focus

That is 98 bytes and twelve new single words, none repeated from the name or subtitle, none plural duplicates. Combined with the name and subtitle, it gives Streakly a chance at searches such as "habit reminder," "daily journal," "mood tracker," "morning routine" and "water tracker," based on the cross-field matching described above.

5. Check before you submit

Run a last pass: no word appears twice across name, subtitle and field; no plurals of words you use; no competitor or trademark; every keyword longer than two characters; byte count at or under 100. Remember the field only changes with the next approved version.

6. Track and iterate per release

After approval, track the ranks of every term you targeted daily for two to four weeks. Keep the words that brought you into the top results, replace those where you stayed invisible, and swap in candidates from your list. One focused change per release makes the result readable.

Common mistakes

Let Searvia pack it for you

If you track your keywords in Searvia, the Metadata simulator on your app's Metadata tab has a Pack keyword field button: it fills the 100 bytes with your best tracked words first, leaves out words already in your title or subtitle, flags repeats and length problems, and shows which tracked keywords you gain or lose against your current listing. You can then copy the field or publish it to App Store Connect from the same tab. The steps are in our keyword field guide.