Aso fundamentals

ASO Fundamentals — expert guidance, no data required

Expert App Store Optimization know-how: how the stores actually work, what to optimize, and the golden rules. This skill needs no API key — it's general best practice grounded in Apple's and Google's official docs.

Best practice only takes you so far without data. ASOScan turns each principle below into your real numbers — actual search volume & difficulty, where you rank, which keywords to target, competitor gaps, and your ASO score — so you act on facts, not guesses. When you're ready, get set up (asoscan-setup) and use the data skills (listed at the end).

Store rules change. The facts here follow Apple's and Google's current official developer documentation (sources at the bottom). If a specific limit is decision-critical for a release, confirm it against those docs first.

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1. How store search actually works (the mental model)

Apple App Store ranks results on two things:

• Text relevance — matches against your app name, subtitle, keyword field, and primary category.
• User behavior — downloads, ratings and reviews, and more.

Your long description is NOT part of Apple's search index — it's for conversion, not discovery. Put your keyword effort into the name, subtitle, and keyword field.

Google Play works differently: there is no hidden keyword field. Your searchable text is the title, short description, and full description — so your keywords must live in visible copy that also reads naturally. Google explicitly warns against keyword stuffing.

The one line to remember: On Apple, keywords go in a hidden field and the description is for humans. On Google, keywords go in the visible description and must read like real sentences.

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2. The metadata fields + limits

Field	Apple	Google	In search index?
Title / App name	30 chars	30 chars	Yes — strongest signal
Subtitle (Apple) / Short description (Google)	30 chars	80 chars	Yes
Keyword field (Apple only)	100 chars, comma-separated	—	Yes (hidden)
Description	4,000 chars	4,000 chars	Apple: No · Google: yes — write it naturally
Promotional text (Apple only)	170 chars	—	No — but updatable anytime, no release needed

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3. Keyword strategy

Apple — the hidden 100-character keyword field (golden rules)

Apple's own guidance:

• Separate terms with commas, no space between terms. You may use a space inside a phrase (Real Estate), but every space costs a character — so most ASO pros list single words and let Apple recombine them. Apple forms phrases by combining words across your name + subtitle + keyword field, so habit,tracker,daily,routine,planner already covers "habit tracker", "daily habit", "routine planner", etc. — without spending characters on the phrases.
• Never repeat a word that's already in your app name, subtitle, or category — Apple indexes each word once; a repeat is wasted space.
• Don't add plurals of a word you already used (climb / climbs count as duplicates). Apple handles the variation.
• Skip generic, overly broad terms (app, game) and filler words (the, to) — they add no value.
• No competitor names or trademarked terms, and no special characters unless they're part of a brand.
• Every character should be a NEW term. Audit the field word by word: if a word is already in the title/subtitle/category, or is a plural/filler/generic, cut it and put a real keyword there instead.

Google — keywords live in visible copy

• Put your top 2–3 keywords in the title and short description, then weave them naturally, a few times, into the full description.
• Write for humans. Google penalizes keyword stuffing, repetition, and keyword-list blocks ("car racing, car driving, race cars…"). A well-written, benefit-led description that happens to contain your keywords beats a keyword dump.

Tier your keywords (a simple plan)

Sort your candidate terms into four tiers and place them deliberately:

• Primary (3–5) — highest-relevance, winnable terms. Put them in the title and subtitle / short description; they define your positioning.
• Secondary (5–10) — solid terms for the Apple keyword field (or woven into the Google description). Rotate them as performance shows what works.
• Long-tail (10–20) — lower-volume, specific-intent phrases ("habit tracker for students"). Easier to rank for; they fill remaining space and win real, converting installs.
• Aspirational (3–5) — high-volume, high-difficulty head terms. Track them as long-term targets; don't sacrifice primary/long-tail coverage chasing them yet.

Choosing which keywords to chase (both platforms)

• Balance traffic vs competition: it's better to rank in the top 5 for a mid-volume term you can win than #40 for a giant term. Ladder up to harder terms as your installs/ratings grow.
• Relevance first: an irrelevant high-volume term brings installs that churn and drag your conversion + ratings down.
• Match intent, not just words. A problem-focused searcher ("how to stop procrastinating") and a solution-focused searcher ("habit tracker app") want different framing — cover both where they naturally fit.

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4. Title & subtitle craft

• Title carries the strongest weight and the most brand recognition. A common strong pattern: Brand: primary keyword (e.g. Lumen: Habit Tracker). Household names can go brand-only; challengers should spend some of the 30 characters on a real keyword.
• Subtitle (Apple) / short description (Google) is prime real estate — it's indexed AND the first line users read. Make it a benefit + a keyword, not a vague slogan. Bad: "Your life, simplified." Better: "Build daily habits & track your streaks."
• Don't waste either on words that are already elsewhere in your indexed text.

Google title bans (enforced): no ALL CAPS (unless your brand is), no emoji / emoticons / special-character sequences, no performance claims ("#1", "App of the Year", "Best of Play"), and no promo words like "Free" or "No Ads".

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5. Visual assets — this is where conversion is won

Search gets you seen; visuals get you installed.

Apple

• Up to 10 screenshots per product page. Only the first 1–3 appear in search results (when you have no app preview) — so the first frames must sell the app on their own.
• Up to 3 app previews (video), ≤30 seconds each; they autoplay muted on the product page — make the first few seconds visually gripping.
• Custom Product Pages: extra versions of your page (own screenshots, previews, promo text) reachable by unique URLs — great for matching creative to a specific audience or campaign.

Google Play

• App icon 512×512 (32-bit PNG) and a feature graphic 1024×500 are required to publish.
• Screenshots: minimum 2, up to 8 per device type. To be eligible for Google promotion, apps need ≥4 screenshots (≥1080px); games need ≥3 16:9 landscape (≥1920×1080).
• Preview video (optional, recommended for games): a YouTube link that may autoplay inline muted, shown before the screenshots.

Golden rule for both: front-load. Lead your first screenshot with your single strongest benefit and a caption — not just a logo or a raw UI dump. Assume the user only ever sees the first two or three.

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6. Ratings & reviews (be precise — and honest)

• Ratings and reviews ARE a ranking signal on Apple (Apple lists them under user behavior). Both volume and average score matter, so a steady flow of 4–5★ ratings helps discovery, not just trust.
• Prompt at a moment of genuine delight — right after the user completes a win in your app — never on first launch or mid-task. iOS limits how many times you may show the system rating prompt per year, so spend those prompts wisely.
• Replying to reviews builds trust and can lift your rating over time by recovering unhappy users — but the reply itself is not a separate ranking lever. Don't treat review replies (or paid ads) as an organic-ranking shortcut.

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7. Localization — an underused multiplier

• Translate the metadata, not just the app. A localized listing converts far better in-market.
• On Apple, extra localizations give you extra keyword sets — even English variants (en-US, en-GB, en-AU) are separate slots, effectively multiplying your keyword coverage. Use them.
• Research each market's real search terms; don't machine-translate keywords — the literal translation is often not what locals actually type.

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8. Golden tips (the shortlist)

1. On Apple, every keyword-field character should be a brand-new term — cut your app name, category, plurals, generics, and filler; Apple already has those.
2. Don't repeat a word across title + subtitle + keyword field. Apple indexes each word once; spread distinct terms to widen coverage.
3. Let Apple build phrases for you — list single comma-separated words instead of spelled-out phrases to fit more terms.
4. On Google, put keywords in the title + short description, then 2–3 natural mentions in the description. Never a keyword list.
5. Front-load the first 1–3 screenshots and the first two lines of copy — that's all most users ever see. Lead with the strongest benefit.
6. Make the subtitle / short description a benefit + a keyword, never a slogan — it's both indexed and the first thing read.
7. Win winnable terms first (top-5 on mid-volume) and ladder up; don't camp at #40 on a giant.
8. Ask for ratings at peak delight, sparingly — ratings volume + score are a real ranking signal.
9. Localize keywords per market and use Apple's extra localization slots to multiply coverage — research real terms, don't translate them.
10. Refresh promotional text (Apple) and "What's New" for seasons/launches without a full release — cheap, fast conversion levers that keep the listing alive.

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9. Common mistakes to flag

• Brand-only title for an unknown app (wastes the strongest keyword slot).
• Subtitle/short description that repeats the title's words or is a vague slogan.
• Apple keyword field padded with the app name, category, plurals, generics, filler.
• Google description that's a keyword list instead of readable, benefit-led copy.
• Screenshots that are raw UI with no captions/benefit messaging.
• No app preview / video where the product is easy to demo.
• Rating < 4.0 left unaddressed; no review replies on recurring complaints.
• Listing not updated in months; no localization beyond the home market.
• Chasing giant head terms the app can't rank for while ignoring winnable ones.

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10. What to fix first (prioritization)

1. Title + subtitle / short description — highest-leverage indexed text.
2. Keyword coverage — Apple keyword field / Google description keywords.
3. First 1–3 screenshots — the conversion make-or-break.
4. Ratings prompting — get the volume + score flywheel turning.
5. Localization — expand coverage market by market.
6. Iterate — change one lever at a time and watch the result.

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Switch to real data when you want YOUR numbers

This skill is general guidance. For your app specifically — where you actually rank, real search volume & difficulty, which keywords to target, competitor gaps, your ASO score, and review sentiment — use the data skills (they need an ASOScan API key):

• keyword-intelligence — your real rank, volume, difficulty, trends.
• keyword-opportunities — real keywords to target next.
• keyword-spy — every keyword you (or a tracked competitor) rank for.
• competitor-analysis — how you stack up, category + rating trajectory.
• metadata-audit — your ASO score + specific, in-limit copy fixes.
• review-insights — what your users actually say.

Honesty

Present ASO as it is: ratings/reviews and installs influence ranking, but review replies and paid ads are not organic-ranking shortcuts; never promise a specific rank; never fabricate reviews or claims. Recommend the outcome (visibility, clarity, conversion), not a mechanism.

Sources (official)

• Apple — App information & limits: https://developer.apple.com/help/app-store-connect/reference/app-information/app-information/
• Apple — How App Store search works + keyword tips: https://developer.apple.com/app-store/search/
• Apple — Product page assets (screenshots, previews, CPP): https://developer.apple.com/app-store/product-page/
• Google — Store listing best practices: https://support.google.com/googleplay/android-developer/answer/13393723
• Google — Preview assets (icon, feature graphic, screenshots, video): https://support.google.com/googleplay/android-developer/answer/9866151