App Store keyword field: 15 rules, myth vs. evidence

Apple describes the App Store keyword field in two places and gives two different sizes. As of September 2026, App Store Connect Help says you "can provide up to 100 bytes of content." Apple's product page guide says keywords "are limited to 100 characters total." In English those are the same thing. In Japanese, Hindi or Thai, a byte reading would shrink the field to about a third.

The field is worth getting right. In Apple's 2022 worldwide App Store data, 70% of visitors used search to discover apps, and almost 65% of downloads happened directly after a search (Apple Ads, App Store). Yet nobody outside your team can see your keyword field, so popular guides disagree on commas, plurals and even the unit of the limit.

Below are 15 rules, each with a verdict and a named source, plus a test for what the documentation leaves open. When you're ready to apply them, clean your field in the free Keyword Field Optimizer.

Last updated Sep 25, 2026. We recheck this page when Apple changes its keyword documentation.

All 15 rules on one screen. Each number jumps to its evidence.

How is the 100-character limit actually counted?

Count in characters, commas included, up to 100 per localization. As of September 2026, Apple's product page guide says keywords "are limited to 100 characters total, with terms separated by commas and no spaces" (Apple Developer, Creating your product page). App Store Connect Help still says "up to 100 bytes" (Platform version information). The evidence below sides with characters.

Rule 1 · Is the keyword field 100 bytes or 100 characters?

Outdated Characters. The byte limit was real once. On June 3, 2013, iTunes Connect moved from bytes to "100 characters (including spaces and commas) for any language" (iBabbleOn, 2013). The "bytes" wording in today's help page looks like a leftover from that era.

Later evidence points the same way. In a 2022 thread on Apple's Developer Forums, a Thai-and-Latin keyword string saved through the App Store Connect API at exactly 100 characters. By our count, that string is 220 UTF-8 bytes. A 106-character version failed with ENTITY_ERROR.ATTRIBUTE.INVALID.TOO_LONG. The reply that counted both strings came from a community member, not Apple staff.

The newest data agrees. In July 2026, Applyra reported that a Thai keyword field of exactly 100 characters, 300 bytes, was accepted (Applyra, App Store & Google Play Character Limits). It doesn't say whether it used the web form or the API. So plan in characters, and run the test below if a CJK, Indic or Thai field sits right at 100.

How much would a byte limit matter? In sample fields we computed, French runs about 1.08 UTF-8 bytes per character, Japanese about 2.5 and Hindi about 2.7. A byte limit would barely touch French but cut the other two by 60% or more. The evidence says that doesn't happen.

Rule 2 · Does one visible letter equal one character?

Likely myth Probably not. Apple appears to count Unicode code points, not the letters you see. In the same 2022 forum thread, Swift reported the saved string as 91 characters, because Swift counts visible letters (grapheme clusters). The replier counted it as exactly 100, and it saved at that length. The gap is Thai vowel and tone marks, which are separate code points that Swift folds into the letter before them.

That matters for Indic scripts. Nine of the 11 languages Apple added on March 31, 2026 use them (Apple Developer News, 2026). Hindi "कि" looks like one letter but is two code points, so every vowel sign costs its own character. Emoji and decomposed accents are still open (T8 and T9 below). For the name and subtitle, see every field's limit in one table.

Rule 3 · Do commas count toward the limit?

Myth They count. Some widely read guides disagree: App Radar's keyword field guide says the limit "excludes commas used as separators" (App Radar, updated March 2024). The evidence says otherwise. Apple's 2013 change covered "spaces and commas," the 2022 API case counted them, and Apple's guide puts the separators inside the 100. The cost adds up. A 14-keyword field spends 13 of its 100 characters on commas. That's the price of the format, not waste.

Rule 4 · Are spaces after commas harmless?

Myth No. Apple's guide says "no spaces," and the field is split on the comma alone. The replier in the 2022 forum thread put it plainly: "the space is wasted and still counts as a character." Here's the arithmetic on one list. These 14 words fill exactly 100 characters with commas only: habit,tracker,journal,planner,routine,streak,goal,focus,reminder,daily,mood,diary,wellness,checklist. With a space after each comma, they need 113. Two keywords fall out.

Rule 5 · Must every keyword be longer than two characters?

Confirmed That's Apple's rule. App Store Connect Help describes the field as "one or more keywords (each greater than two characters)." Nobody has shown publicly how it's enforced: does App Store Connect refuse "ai" or "tv" at save, or accept it and ignore it? Test string T11 answers the first half.

If a two-letter term like AI, TV or VR matters, don't rely on the keyword field. Apple's docs set no such minimum for the name or subtitle, so those are the likelier home. Check search results after release.

How does Apple match the words in your keyword field?

Within one localization, words from your name, subtitle and keyword field combine into the searches you can rank for. As of 2026, Apple's search guide says plurals such as "climbs" and "climb" "are considered duplicates" (Apple Developer, App Store search). It also tells you not to repeat words from your name, subtitle or category. Beyond that, it's inference. The verdicts get more cautious as this section goes on.

Rule 6 · Should you write keywords as full search phrases?

Partly true Phrases are allowed. Apple's own example is Property,House,Real Estate. But single words combine with every other indexed word in the same localization, so they usually buy more searches per character. We found no public evidence that an exact phrase outranks the same words entered singly. A developer asked exactly that on Apple's forums in November 2023, and the thread has no replies. Use a phrase only when the words mean something different apart.

Rule 7 · Does repeating a title word in the keyword field boost it?

Myth No. Apple's search guide says not to repeat words from your name, subtitle or category. App Store Connect Help adds that your app is already "searchable by app name and company name," so your developer name doesn't belong in the field either. Repetition doesn't add weight; it only spends characters. Deciding what earns a place in the title is a separate call, and a bigger one.

Rule 8 · Are plurals free?

Partly true Half right. Apple treats a regular plural as a duplicate of the singular you've entered, so never write both. But the search results aren't identical. AppTweak compared 100 singular/plural pairs in the US, France and Spain (AppTweak, updated January 2025). On iOS, only 4.4 of the top 10 apps for a singular also ranked top 10 for its plural, against 5.6 on Google Play. "hotel" and "hotels" shared 8 apps; "casino" and "casinos" shared 2.

So pick the form on purpose: compare both forms' popularity and competition. The gap can be large. In February 2014, Sensor Tower found more than 10 times as many apps competing for "download" as for "downloads" (Sensor Tower, 2014). That's an old snapshot, but the less crowded form can still be the easier win.

Rule 9 · Does plural matching work in every language?

Unproven Don't count on it, especially for irregular plurals. Apple's example is an English "-s" plural. AppTweak's keyword field guide notes that in France, FarmVille "does rank for 'animal,' but not 'animaux'" (AppTweak, updated August 2024). That's one example, not a study, and it's the only public one we found. For non-suffix plurals such as animal/animaux, child/children or mouse/mice, treat each form as its own keyword until a canary test says otherwise.

Rule 10 · Does Apple match -ing and -ed forms?

Unproven There's no public evidence either way. Apple documents plural handling and nothing broader. So treat "edit" and "editing" as separate keywords, with separate popularity, until you've checked. If the difference matters to your app, the canary test in the testing section answers it within days of a release.

Rule 11 · Do filler words, "app", category names and symbols add reach?

Myth They add nothing. Apple's product page guide lists them as waste: the word "app," category names, duplicate words, and special characters such as # or @, which "don't carry extra weight when users search for your app." Its search guide adds generic terms like "game" and filler like "the" and "to." Those characters belong to words people actually type, which come from choosing which keywords to target.

Can you put competitor names in the keyword field?

No. As of September 2026, App Store Connect Help says "Names of other apps or companies aren't allowed." App Review Guideline 2.3.7 warns against packing metadata with "trademarked terms, popular app names." It adds that "Apple may modify inappropriate keywords at any time or take other appropriate steps to prevent abuse" (Apple, App Review Guidelines).

Rule 12 · Are competitor names safe because the field is hidden?

Myth Hidden from users isn't hidden from Apple. Apple calls improper keyword use "a common reason for App Store rejections," and trademark owners can file an App Store content dispute. Enforcement is uneven: Gummicube's August 2024 guide calls the tactic "technically against Apple's guidelines," with "a degree of risk for rejection" (Gummicube, 2024). The trade is lopsided: a rejection blocks your whole release, for at best a low-relevance rank.

There are two clean routes. Your own former brand name is neither another app nor another company, so after a rebrand it can stay in the field to keep your old name findable. And in Apple Ads, bidding on a competitor's name is a common tactic that never touches your metadata.

When do keyword changes take effect?

Only with a new app version. Keywords are a version-level property in App Store Connect, so every change goes through App Review. Promotional text is different. As of 2026, Apple says you can update it "at any time without having to submit a new version of your app" (Apple Developer, Creating your product page).

Rule 13 · Can you edit keywords any time?

Myth No. Build keyword changes into your release train. Batch every localization's keyword edits into one version, then leave them alone long enough to measure. A keyword change inside a big feature release is harder to read, because the release can move conversion too.

Rule 14 · Do new keywords rank the next day?

Partly true Some do, but day one isn't the verdict. App Store Connect Help says updated information can take up to 24 hours to appear (View and edit app information). In AppTweak's October 2025 guide, Spotify went from unranked to #11 for "podcast" within a day. Yet iOS rankings "stabilize around 4 weeks after a new build is uploaded" (AppTweak, 2025).

So change each locale's field every four weeks at most, and judge at week four, not day two. Edit at day five and neither version ever settles. The full timeline is in the three clocks of ASO timing.

Do you really get only one keyword field?

No. You get one 100-character field per localization, and a storefront can index several. As of September 2026, Apple lists English (U.S.) plus Arabic, Chinese (Simplified), Chinese (Traditional), French, Korean, Portuguese (Brazil), Russian, Spanish (Mexico) and Vietnamese for the United States (App Store Connect Help, App Store localizations). Fill all 10 and that's up to 1,000 characters of US keyword space (Appfigures, 2023).

Rule 15 · Is the keyword field one 100-character box?

Myth It's one box per localization, with two limits. First, words don't combine across localizations. AppTweak's cross-localization guide gives an example. With "bus" only in English (U.S.) and "metro" only in Spanish (Mexico), an app ranks for each word in the US but "will most likely not be indexed for 'metro bus'" (AppTweak, updated November 2025). Keep phrase partners in the same localization, and see which localizations your storefront indexes before you split words up.

Second, the same field is your custom product page keyword pool. Apple lets you assign keywords "from your latest approved app version" to a custom product page (App Store Connect Help, 2026). That routes searchers to the page; it doesn't add characters. Google Play works differently again: it has no hidden keyword field and reads your visible listing text instead.

How do you test the keyword field yourself?

Paste calibrated strings into the keyword box of a draft version in App Store Connect, one whose status is Prepare for Submission, and record which ones save. Two strings, T3 and T5, settle bytes versus characters on their own: each is 102 UTF-8 bytes but only 51 or 34 characters. The rest show which characters Apple counts. Don't submit the draft, and revert it when you're done.

1. Calibrate. Paste T1, exactly 100 ASCII characters with 13 commas. Then paste T2, which adds one "s." If T1 saves and T2 doesn't, the limit is 100 and commas count.
2. Bytes or characters. Paste T3 and T5. If either saves, the limit isn't 100 UTF-8 bytes. T4, T6 and T10 (100 characters, 200 to 300 bytes) then confirm a 100-character ceiling.
3. Which characters. T7a and T7b test code points against visible letters. T8 tests whether Apple normalizes decomposed accents. T9 tests code points against UTF-16 units. Use T9 as a test only; emoji don't belong in a real field.
4. Repeat through the API (optional). Update the keywords attribute of an appStoreVersionLocalizations resource with a PATCH request. In the 2022 forum case, an over-limit string returned ENTITY_ERROR.ATTRIBUTE.INVALID.TOO_LONG.
5. Record and revert. Note the date, UI or API, locale and result for each string, and take a screenshot. Then restore the draft's real keywords.

We publish this as a method, with no results column. A result is only worth citing with its date, locale and screenshot, so keep that record when you run it. The byte widths follow the UTF-8 standard (IETF, RFC 3629).

Part B, optional: a canary indexing test. Saving shows what Apple accepts, not what it matches in search. For that, ship one coined token, a made-up word nobody else uses, on a low-stakes app you own. AppTweak and Phiture used invented keywords such as "enuk1201" to map cross-localization this way (AppTweak, 2025). Between 24 and 72 hours after release, search for the token's plural, its -ing form and combinations with your subtitle words.

Two caveats apply. Apple lists irrelevant terms as a rejection reason, so use one token and remove it in your next version. And a canary shows whether a form is matched, not how strongly it ranks. That's enough to check Rules 5, 9, 10 and 15 on your own app.

What should you check before you submit?

Seven checks, in this order, drawn from the rules above that hold up. The first two, and the name-and-subtitle half of the third, are mechanical enough for a tool.

1. 100 characters or fewer, commas included.
2. No spaces after commas.
3. No word from your name, subtitle, category or company name.
4. One form per singular/plural pair, chosen on purpose.
5. No keyword of two characters or fewer.
6. No names of other apps or companies.
7. Every localization your storefronts index, filled with its own words.

Run your list through the Keyword Field Optimizer: it strips title and subtitle words, filler and duplicates, then trims to 100. Then use our 60-check ASO audit to score the rest of your listing. Want the whole keyword set rebuilt for each market? That's our keyword strategy work.

The bottom line

The field is small, hidden and loosely documented, so precision pays:

• Unit: 100 characters per localization, commas included; "bytes" is outdated.
• Format: commas, no spaces.
• No repeats: nothing from your name, subtitle, category or company name.
• Plurals: one form per pair, chosen deliberately.
• Policy: no other apps' or companies' names.
• Timing: changes ship with a version; judge at week 4.
• Scope: one field per locale, and fields don't combine.

Clean your field in the free Keyword Field Optimizer. To see which words are missing from each localization your storefronts index, book a free 30-minute call.