App Store Keyword Field

What Is the App Store Keyword Field?

The App Store keyword field is a 100-character hidden metadata field available exclusively to iOS developers through App Store Connect. It allows you to specify comma-separated keywords that Apple uses for search indexing. Unlike the title and subtitle, the keyword field is never displayed to users — it exists solely to help the search algorithm understand what your app is about.

The keyword field is the most flexible metadata field for ASO. You can update it with each app version, test different keyword combinations, and optimize without affecting the user-facing elements of your listing.

Keyword Field Rules

Apple enforces specific formatting requirements for the keyword field:

• 100-character maximum. This is a hard limit — content beyond 100 characters is truncated.
• Comma-separated, no spaces. Use word1,word2,word3 — not word1, word2, word3. Spaces after commas waste characters.
• Single words only. Enter individual words, not multi-word phrases. The search algorithm automatically combines words across your title, subtitle, and keyword field to match multi-word search queries.
• No duplicates. Don't repeat words that already appear in your title or subtitle — they're already indexed from those fields. Duplicating them wastes keyword field characters.

Maximizing 100 Characters

With only 100 characters, efficiency is critical. Here are proven strategies:

1. Use Singular Forms Only

Apple's search algorithm handles pluralization automatically. Including "tracker" indexes your app for both "tracker" and "trackers." Never include both singular and plural forms — it wastes characters on a duplicate.

2. Skip Articles, Prepositions, and Common Filler

"The," "a," "an," "for," "with," "my" — these words consume characters and add no search value. The algorithm combines words from different fields, so "best budget app for tracking" is better reduced to just the content words: "best,budget,track" (the algorithm already has "app" from your title category).

3. Avoid Repeating Title/Subtitle Words

If your title is "BudgetPal: Expense Tracker" and your subtitle is "Savings Goals & Money Plans," you've already indexed: budget, pal, expense, tracker, savings, goals, money, plans. Don't repeat any of these in the keyword field — use all 100 characters for new keywords.

4. Use Short Synonyms

When two words mean similar things, use the shorter one to conserve characters. "Finances" (8 chars + comma) vs. "money" (5 chars + comma) saves 3 characters for another keyword.

5. Include Misspellings Strategically

Common misspellings of relevant terms can capture searches from users who type quickly. However, Apple may reject submissions with obvious misspellings, so use this carefully and only for naturally ambiguous terms.

Character Efficiency by Language

The 100-character limit applies regardless of language, but different scripts pack different amounts of meaning per character:

• Japanese and Chinese: Each character can represent an entire concept. Where English needs "expense tracker" (15 chars), Japanese might use "家計簿" (3 characters). This means 100 characters in Japanese can contain 3–5x more keywords than English.
• Thai: Similar density advantages — Thai script packs more meaning per character than Latin alphabets.
• German: Compound words are long ("Haushaltsbuch" = household book/budget tracker), consuming more characters per concept than English.
• Indonesian and Vietnamese: Latin-based scripts with reasonable character efficiency.

How the Search Algorithm Uses the Keyword Field

The App Store search algorithm combines words across all your metadata fields. If your title contains "Budget" and your keyword field contains "planner," your app can match the search query "budget planner" — even though the full phrase doesn't appear together anywhere.

This means the keyword field's role is to expand your searchable vocabulary, not to create complete phrases. Each word you add creates potential combinations with words in your title and subtitle, multiplying the number of search queries your app can match.

Common Mistakes

• Using spaces after commas. "budget, tracker, planner" wastes 2 characters on spaces that serve no indexing purpose. Use "budget,tracker,planner" instead.
• Including multi-word phrases. "expense tracker,budget planner" treats "expense tracker" as two separate words anyway. Just use "expense,tracker,budget,planner" — same result, no ambiguity.
• Repeating title/subtitle words. The most common waste of keyword field space. Every character spent re-indexing an already-indexed word is a character not spent on a new keyword.
• Using fewer than 90 characters. The recommended minimum is 90 characters — anything less means you're leaving potential keywords on the table.
• Not localizing per market. The keyword field can be set differently for each localization. Running the same English keywords in every market wastes the opportunity to target local-language terms.

How RespectASO Helps Optimize the Keyword Field

RespectASO's multi-keyword search lets you evaluate up to 20 keyword candidates at once, scoring each on popularity, difficulty, and opportunity. This helps you choose the highest-value keywords for your limited 100 characters. The seven-category classification system identifies Sweet Spots and Hidden Gems — the keywords that should be prioritized in your keyword field.