Most developers fill the App Store keyword field once, during the first submission, under deadline pressure. Then they ship and move on. The field does not show up in analytics. No user ever asks about it. And so it gets ignored for months, sometimes indefinitely.

That is a mistake that compounds quietly. Apple uses the keyword field every time someone searches. A field that is half-empty, duplicate-heavy, or filled with phrases instead of tokens is costing you impressions on every search that fires.

This post covers what the keyword field actually does, five specific ways developers waste it, how Apple’s algorithm processes what you put in it, and a step-by-step workflow for building a field that uses all 100 characters well.

1. What the keyword field actually is (and why users never see it)

Open App Store Connect and you will find a field labeled “Keywords” under your app metadata. It accepts up to 100 characters including commas. You fill it in, submit your build, and Apple uses it to determine which search queries your app is eligible to appear for.

Users never see this field. It does not appear on your product page, in search results, or anywhere a user might read it. It is invisible: a signal sent directly to Apple’s indexing system.

That invisibility is part of why it gets neglected. After spending hours on screenshots, store copy, and your subtitle, the keyword field feels like a technical detail. It is not. Because users do not see it, every character is purely an indexing decision. There is no aesthetic tradeoff, no readability concern. Just coverage.

Apple gives you 100 characters to expand your search reach beyond what fits in your visible metadata. Every unused character is a query you are not appearing for. Every misused character is the same outcome.

2. The five most common ways indie devs waste characters

Most keyword field problems follow recognizable patterns. Here are the five that show up most often.

1. Duplicating your app name or subtitle

Apple indexes your app name and subtitle automatically and at high weight. Repeating those same words in the keyword field does nothing — the system has already processed them. If your app is named “Focus Timer”, putting timer or focus in the keyword field wastes characters that could cover new ground.

2. Adding spaces after commas

The keyword field is comma-separated, and spaces count toward your character limit. focus,notes,tasks is 17 characters. focus, notes, tasks is 19 characters. Two wasted characters per term. Across a full field, that is enough to cost you one or two complete keyword tokens.

3. Using phrases instead of individual tokens

time management costs 15 characters including the comma. time,management also costs 15 characters, but now you have two independent indexing tokens instead of one phrase. Apple matches keywords individually, so two tokens cover more queries than one phrase at the same character cost.

4. Targeting terms you cannot realistically rank for

Words like app, free, best, and overly broad category terms are dominated by well-resourced apps with strong review velocity and high download counts. Using those characters on a term where you have no realistic shot at ranking is equivalent to leaving them empty.

5. Leaving the field short

The most common and most fixable waste. A field at 60 or 70 characters means 30 to 40 characters of indexing surface unused. Apple does not penalize a full field. Use every character available.

Quick check: Count your current keyword field characters right now. If it is under 85, this post is for you.

3. What Apple’s algorithm actually does with keyword tokens

The keyword field is not processed as a phrase or a block of text. Apple tokenizes it.

Given pomodoro,focus,countdown, Apple creates three independent indexing tokens: pomodoro, focus, and countdown. A user searching “focus countdown” can match on your app because both tokens are individually present in the field.

This tokenization behavior has direct practical consequences.

  • Individual words beat phrases. Apple matches tokens, not combinations. Two separate tokens reach more queries than one multi-word phrase of the same character length.
  • The keyword field extends coverage, not authority. Your app name carries the strongest ranking signal. The keyword field tells Apple what else to index your app for — it does not boost you above apps with stronger names and more downloads.
  • Apple normalizes common variants. Plural and singular forms of common words are often treated as equivalent, so note and notes typically reach the same queries. No need to include both.
  • Locale matters. English keywords apply to English App Store regions. For other markets, you set separate keyword fields in the localized metadata.

The practical conclusion: maximize the number of distinct, non-overlapping tokens you send Apple. Short and numerous beats long and sparse.

4. How to build a 100-character keyword field from zero

Here is a repeatable five-step process for filling the field correctly.

Step 1: Build a candidate list

List every term someone might search to find an app like yours. Include problem-based queries (“focus timer for studying”), feature-specific terms (“Pomodoro”, “time blocking”), and adjacent category terms (“task queue”, “study app”). Aim for 30 to 50 candidates before filtering.

Step 2: Remove terms already in your name and subtitle

Apple has those covered at higher weight. Strike them from the list entirely.

Step 3: Convert phrases to individual tokens where both words stand alone

“Time management” becomes time,management. “Task tracker” becomes task,tracker. When both individual words make sense as standalone search terms, break them.

Step 4: Sort by estimated search demand and cut from the bottom

Not all terms are searched equally. Prioritize terms where users are actually searching at a volume that makes the impression worthwhile. Tools like Marteso surface search volume estimates for App Store keywords. When trimming for the character limit, cut the lowest-demand terms first.

Step 5: Assemble, format, and count

No spaces after commas. Count total characters including commas. Target 95 to 100 characters.

Worked example

For a focus timer app after removing overlap with name and subtitle:

pomodoro,concentration,deepwork,study,countdown,distraction,blocking,flow,tracking,sessions,planner

Character count: 98. Covers eleven tokens across multiple user intent clusters. No wasted whitespace, no redundancy with visible metadata.

Compare to a naive fill: pomodoro timer, focus timer, study timer, productivity app, time management — 73 characters, all phrases, stops short of 100, only 5 tokens.

5. Before/After: what a real keyword field optimization looks like

App: “Daily Log” (journaling app, subtitle: “Write. Reflect. Grow.”)

Before (52 characters):

journal, diary, daily notes, writing app, log book

Problems with this field: spaces after commas using 5 unnecessary characters; journal likely covered by the app name; writing app and log book are phrases with weak token coverage; field is only 52% full.

After (97 characters):

diary,reflection,gratitude,mood,mindfulness,habit,tracking,wellness,streak,prompts,planner,mental

Changes made: spaces removed, name-duplicates dropped, phrases broken into tokens, eight new keyword tokens added covering adjacent user intent categories.

What the optimized field now reaches that the original did not:

  • Users searching “gratitude journal” (via gratitude)
  • Users searching “mood tracker” (via mood + tracking)
  • Users searching “habit streak app” (via habit + streak)
  • Users searching “wellness planner” (via wellness + planner)
  • Users searching “daily reflection” (via reflection)

Same 100-character budget. Five intent categories newly in range.

6. How Marteso takes the guesswork out of keyword selection

Step 4 in the workflow above is where most developers lose confidence. You can build a candidate list manually, but without data, you are guessing at which terms are worth the characters.

Marteso shows search volume estimates for App Store keywords, surfaces the terms your competitors rank for that you are not covering, and flags overlaps between your keyword field and your visible metadata so you are not spending characters on terms Apple has already indexed from your title or subtitle.

The result is a keyword field built on actual search signal, not intuition. And one that you can refresh with each update cycle as your app evolves and as search trends shift.

If you have not looked at your keyword field in the last 90 days, look now. Apple gives you 100 characters. Every one of them is indexing coverage you either have or you do not.

See which keywords should be in your field. Free on Marteso.