The iOS Keyword Field in 2026: How the 100-Character Field Works

The iOS keyword field is the most misunderstood surface in App Store Optimization — a hidden, 100-character box in App Store Connect that no user ever sees but that quietly shapes which searches your app ranks for. In 2026 the rules haven't changed much, but the discipline they demand has. Get the mechanics wrong and you burn a third of your characters on spaces, plurals, and words Apple already indexes for free.

This guide walks through exactly how the field works, the character-saving rules that separate a wasted field from a tight one, how Apple recombines your words into searchable phrases, and a before/after example you can copy.

What the iOS keyword field is

The keyword field is a 100-character, comma-separated input you set per localization in App Store Connect (under your app version's metadata, not on the public product page). Unlike your app name and subtitle, it is not visible to users — it exists purely to feed Apple's search index.

A few facts worth pinning down:

• It's per localization. Each language you ship has its own 30-character name, 30-character subtitle, and 100-character keyword field. That's a real opportunity: a US English field and a UK English field can carry different terms.
• The 100 characters exclude commas in most counting models, but spaces always count. Treat 100 as your hard budget and spend every character.
• It's one of three indexed text fields. Apple builds its keyword index from your app name, subtitle, and keyword field. The long description is not indexed for keywords — a point App Radar and AppTweak both make explicitly. So the keyword field is one of only three places a search term can "live."

Because nobody reads it, the keyword field is where you put the unglamorous, high-intent terms — synonyms, misspellings, and long-tail variations that would look strange in your visible copy.

The character-saving rules

You have 100 characters and roughly 25–35 keywords' worth of room if you're disciplined. These rules are how you stay disciplined. Most are confirmed by AppTweak, App Radar, and MobileAction.

1. No spaces after commas. Write tracker,budget,expense, not tracker, budget, expense. Every space is a wasted character that buys you nothing. On a full field this single mistake can cost you 8–10 keywords.
2. Don't repeat words already in your app name or subtitle. Apple indexes all three fields together, so a word you used in your subtitle is already in the index. Repeating it in the keyword field is a duplicate that wins you nothing — it just spends characters.
3. Skip plurals — Apple stems them. Add the singular only. Apple's algorithm typically ranks the singular for the plural query automatically, so recipe covers recipes. Including both is a waste.
4. Don't include your category, "app", or "free". Apple implicitly indexes the word "app" and your category name, and commonly handles generic words like "free", "new", and "best". Spending characters on them is pure waste.
5. Use single words, not phrases. Apple recombines words across fields to form searchable phrases (more on this below). If you write budget,planner, Apple can already produce "budget planner." Writing the phrase out yourself just duplicates words and burns commas.
6. Avoid special characters and duplicates. No emojis, no &, no repeated words within the field. They either don't index or eat characters you can't afford.

A blunt way to think about it: if Apple gives you a word for free, don't pay for it.

How Apple builds searchable combinations

This is the rule that makes everything else click. Apple does not only match the exact strings you type. Its search algorithm takes the words from your app name + subtitle + keyword field and recombines them into multi-word search phrases.

Say your metadata contains these words across the three fields:

• App name contributes: budget
• Subtitle contributes: expense, tracker
• Keyword field contributes: planner, bills, savings

Apple can now generate combinations like budget tracker, expense planner, bill tracker, savings planner, and dozens more — without you ever typing those phrases. This is precisely why single words beat phrases: each unique word multiplies against every other word you own.

It also explains why duplication is so costly. A word repeated across fields doesn't get "extra weight" — Apple already has it. You've simply removed a slot that could have held a new word, and therefore a whole new set of combinations.

If you want the full picture of how the name, subtitle, and keyword field interact across your store presence, our App Store optimization guide covers the broader metadata strategy, and the App Store keyword research guide goes deep on finding the words in the first place.

Single vs broad keywords (and relevance)

Not all words are worth a slot. A keyword's value is roughly search volume × your realistic chance to rank × relevance to your app. Two failure modes are common:

• Chasing head terms. A generic, ultra-competitive term like game or photo has enormous volume but you'll rank on page 12 for it — and it eats characters that a winnable long-tail term could use. For most apps, broad head terms in the keyword field are a quiet waste.
• Ignoring relevance. Apple weighs how relevant a term is to your app (informed by metadata and, over time, by tap-and-conversion behavior). Stuffing high-volume but loosely-related words can dilute relevance rather than help it.

The sweet spot is mid-volume, high-relevance, winnable terms — often two-word intents you can assemble from single words. That's where the keyword field earns its keep: it's a place for the specific, high-intent vocabulary your competitors haven't thought to combine.

Fill all 100 characters with keywords that actually rank — research them with Lite ASO.

A worked before/after example

Here's a weak keyword field for a fictional budget and expense tracking app named "MoneyWise: Budget Tracker" with the subtitle "Expense & Bill Planner."

Before (weak — 99 characters, mostly wasted):

budget, budgeting app, expense, expenses, tracker, money app, free finance app, best budget

What's wrong with it:

• Spaces after every comma — roughly 8 wasted characters.
• budget, expense, tracker, planner all repeat words already in the name/subtitle — duplicates that win nothing.
• budgeting app, money app, finance app include "app" — Apple adds that for free.
• expenses is a plural of expense — Apple stems it.
• free and best — generic words Apple commonly handles.

After clearing all that, only money and finance survive as genuinely new words. The field is almost entirely waste.

After (optimized — every word new and singular):

savings,debt,bill,subscription,spending,income,budgeting,finance,wallet,cashflow,receipt,loan

The "after" field carries twelve fresh, relevant single words — none of which repeat the name or subtitle. Combined with the words already in the name and subtitle, Apple can now generate combinations like bill tracker, debt planner, subscription budget, savings tracker, and spending planner — none of which the "before" field could produce.

How to choose what goes in the field

The mechanics are easy; the hard part is deciding which words deserve a slot. This is research, not guesswork. For each candidate keyword you want three numbers:

1. Search volume — is anyone actually searching this term? A perfectly winnable keyword nobody types is worthless.
2. Difficulty / competition — can your app realistically break into the top results, given the apps already ranking?
3. Relevance — does the term describe what your app does? Low relevance hurts conversion even if you rank.

Then prioritize: mid-volume, low-to-mid difficulty, high-relevance terms first, and prune anything that's a duplicate, a plural, a phrase, or a head term you can't win. This loop — pull candidates, score them, drop the losers, repeat — is exactly where a keyword tool earns its keep. Doing it by gut feel is how fields end up full of free, best, and plurals.

This is the core workflow Lite ASO is built for: it surfaces keyword volume and difficulty scores, tracks what competitors rank for so you can find gaps, and (via MCP) lets you run the whole research loop straight from ChatGPT or Claude.

Quick checklist

Before you save that field, run through this:

• Exactly 100 characters used — no slot left empty.
• No spaces after commas.
• No word repeated from your app name or subtitle.
• No duplicate words inside the field.
• Singular only — no plurals.
• No "app", category name, "free", "new", or "best".
• Single words, not phrases — let Apple recombine them.
• No special characters or emojis.
• Every word researched for volume, difficulty, and relevance.
• A separate field for each localization you ship.

Once your keyword field is tight, the rest of your product page does the converting. See our guides on App Store screenshots in 2026 for the visuals, and App Store vs Google Play in 2026 if you're optimizing for both stores at once — Google Play has no hidden keyword field and indexes your full description instead, which changes the whole approach.

The iOS keyword field rewards discipline: 100 characters, no waste, every word earning its place through real research.

Stop guessing — fill all 100 characters with keywords that actually rank. Research volume and difficulty with Lite ASO.