The keyword field
Expert: with sources and numbers. Plain: the same, without them, for beginners.
The hidden 100-byte field. Apple's own rules for it, the bytes-versus-characters question, and how to spend it.
A comma-separated list, invisible to users, set per localization, read by search. It is the only iOS field that exists purely for ranking, which makes it the one place where you can be entirely mechanical.
The rules
Apple’s own description of the field is short and contains four separate rules worth separating out.
A The field holds 100 characters. (Creating your product page, verified 2026-09-19)
A Each keyword must be greater than two characters. Same source.
A The app name and the company name are already searchable, so they should not be duplicated in the keyword list. Same source. This is Apple confirming that the developer name is an indexed surface. See 10-06.
A Names of other apps or companies are not allowed. Same source, and reinforced by App Review Guideline 2.3.7, which prohibits packing metadata with trademarked terms or popular app names. See 30-07 for the trademark exposure this carries.
A The field is localizable and not editable without a new app version. See 10-09.
A Apple states it may modify inappropriate keywords or take other steps to prevent abuse. (Guideline 2.3.7)
A Apple publishes an explicit list of what wastes the field. To maximise the number of words that fit, avoid plurals of words already included in singular form, names of categories and the word “app”, duplicate words, and special characters such as # or @ unless they are part of your brand identity. Apple adds that special characters carry no extra weight in search. (Creating your product page, verified 2026-09-20)
The plurals line is the important one, and it is stronger than the advice usually given for it. Apple telling you not to include a plural you already have in singular is Apple saying the store matches them. That makes it documented rather than folklore, with a real caveat outside English, in CONFLICT-022.
A On separators: terms are comma-separated with no spaces, but a space may be used inside a keyword phrase. Apple’s own example is Property,House,Real Estate. Same source. So a multi-word phrase is permitted; whether it is a good use of the field is a separate question (30-04).
The bytes wording in Apple’s reference, resolved
Apple’s two pages do not agree, and the discrepancy is worth knowing about because it will come back.
- The product page overview says 100 characters.
- The App Store Connect reference says 100 bytes.
For English these are identical. For anything else they would not be: in UTF-8 a CJK character costs 3 bytes, so a strict byte ceiling would mean roughly 33 Chinese characters rather than 100, a threefold difference in some of the largest storefronts in the world.
The working limit is 100 characters, confirmed from App Store Connect use including in non-Latin locales. The reference page’s “bytes” wording is an inconsistency in Apple’s documentation, not the operative limit.
Recorded rather than deleted, so nobody re-derives the byte theory from Apple’s reference page in a year’s time. Full account in CONFLICT-004.
How to work with it
No spaces after commas. A space is a character, and you have 100.
Single words, not phrases. The store combines terms across fields to match multi-word queries, so writing photo editor spends 13 characters to buy what photo,editor buys for 12 while also contributing to other combinations. See 30-04.
Never repeat a word. Repetition adds nothing and costs characters.
Leave out your app name and developer name. Apple says so directly, and it is the most common way people waste a third of the field.
Leave out category names you already rank for by category. Both categories are indexed (10-08), so spending bytes on the category label is usually a duplicate.
Leave out plurals where the singular is present. But verify this per locale rather than assuming it. B Practitioners consistently report that iOS handles simple English plural matching without a separate entry; this is not documented by Apple, and it does not transfer cleanly to other languages.
Fill it. There is no benefit to leaving characters unused. If terms are scarce, the problem is the research, not the field. See 30-01.
What goes wrong
Spending it on brand. Your name and developer name are already indexed. This is the single most common waste.
Writing phrases. Spends bytes on word order the algorithm does not need.
Competitor names. Prohibited by Apple in two separate places, removable at Apple’s discretion, and a trademark risk that sits with your company rather than with the person who added the keyword.
Changing it and expecting immediate movement. It is bound to a version, so the change ships with a release, and ranking movement follows indexing rather than submission. Measure on the cadence in runbooks/quarterly-keyword-refresh, not the next morning.
Re-deriving the byte theory from Apple’s reference page. It is an inconsistency in Apple’s documentation. The limit is 100 characters.
In short
Every fact on this page in one line, with its evidence tier, source and verification date, 7 A · 1 B. Generated from the claim register, so it cannot drift from the page above.
A short, private list, invisible to any shopper, set separately for each country's sign-language, read only by the desk. It's the one piece of your shopfront that exists purely for filing, which makes it the one place you can be entirely mechanical about the choices.
The rules
The centre's own description of this field is short and carries several separate rules worth pulling apart.
It gives you a fixed, small amount of room, and nothing more.
Each word in it has to be more than a couple of letters long.
Your own sign and your company's own name are already searchable, so putting them here again is wasted room. This is the centre confirming, in its own words, that your company name is itself a place the desk reads.
You may not put another shop's or company's name in here. Backed up by the house rule against stuffing a sign with a rival's name too.
It's set per country's sign-language, and locked until your next refit.
The centre says it may quietly edit a word it thinks is inappropriate.
The centre publishes its own list of what wastes this room: the plural of a word you've already written in singular, the name of your own floor or the generic word for "shop" itself, a repeated word, and a special symbol, unless that symbol is genuinely part of your own brand, since the centre says a symbol earns no extra weight anyway.
The plural line is the important one, and worth taking seriously. The centre telling you not to add a plural you've already written in singular is the centre telling you, in its own words, that it matches the two together, though this comes with a real caveat outside English, since not every language pluralises the way English does.
On how to separate words: they're listed one after another with nothing between them, though a single filing entry may itself be more than one word. So a short phrase is technically allowed in here; whether it's a good use of your room is a separate question. See How the centres combine words.
An inconsistency in the centre's own paperwork, resolved
Two of the centre's own reference pages disagree with each other about exactly how this room is measured. Worth knowing about, because it resurfaces.
For plain English text the two ways of counting come out the same. For anything else they wouldn't: some scripts cost more per letter under one way of counting than the other, which would mean a much smaller effective allowance for some of the largest countries in the world.
Treat the shorter, character-based reading as the real, working limit, confirmed from actual use including in non-English sign-languages. The other page's wording is simply an inconsistency in the centre's own paperwork, not the rule that's actually enforced.
How to work with it
No wasted space between entries. Every character counts, and you don't have many.
Single words, not phrases. The desk already combines separate words across your fields to answer a longer question, so writing a two-word phrase spends more room to buy less than writing the same two words separately would. See How the centres combine words.
Never repeat a word. It adds nothing and costs you room you don't have to spare.
Leave out your own sign and your company name. The centre says so directly, and skipping this is the single most common way people waste a big chunk of this field.
Leave out the name of your own floor. Your floor is already read by the desk on its own, so spending room on the floor's own name is usually a duplicate.
Leave out a plural where you've already written the singular. But check this per country's language rather than assuming it always holds. Shopkeepers consistently report that English handles a simple plural without a separate entry; the centre doesn't document this itself, and it doesn't carry over cleanly to every other language.
Use the whole allowance. There's no benefit in leaving any of it unused. If you can't think of enough words worth including, the problem is your homework, not the field. See Where this data actually comes from.
What tends to go wrong
Spending it on your own name. Your sign and company name are already read by the desk. This is the single most common waste of all.
Writing phrases instead of single words. Spends room on an order the desk doesn't actually need from you.
Putting in a rival's name. Banned by the centre in two separate places, removable at the centre's own discretion, and a trademark risk that lands on your company, not on whoever typed it in.
Changing it and expecting an instant result. It's locked to your refit schedule, so the change ships with your next refit, and any movement follows re-filing rather than submission. Measure on the rhythm in Doing a seasonal refresh of your sign words, not the next morning.
Re-deriving the stricter reading from the centre's own inconsistent paperwork. It's a mistake in their documentation. The shorter, character-based reading is the one that's actually enforced.