Introduction
App Store Optimization (ASO) is the mobile equivalent of SEO. Done well, it drives 30–50% of a modern app's organic installs. Done badly — or skipped entirely — it leaves your app invisible in a store with 1.8 million iOS apps and 2.5 million Android apps. This checklist covers everything credible ASO programs do in 2026.
Keyword research
Start with intent-based keyword discovery. Tools: App Annie/data.ai, Sensor Tower, AppTweak, Apple Search Ads suggestions, Google Play Console's suggested keywords. For each candidate keyword, score on search volume, competition (difficulty to rank), and intent alignment with your app.
Target a mix of high-volume head terms (competitive but necessary for visibility) and long-tail terms (lower volume, much easier to rank, higher conversion). A reasonable starter set is 15–25 keywords spanning both.
- Use App Annie, Sensor Tower, AppTweak for keyword data
- Mix head terms + long-tail; 15–25 starter keywords
- Score on volume, competition, intent alignment
App metadata — title, subtitle, keywords, description
App Store (iOS) structure: app name (30 chars), subtitle (30 chars), keyword field (100 chars — not visible to users but indexed), description (4,000 chars, first 3 lines are the only ones users typically read). Google Play structure: app title (30 chars), short description (80 chars), full description (4,000 chars, fully indexed for search).
Rules: keyword stuffing is penalized. Your primary keyword in the title, secondary in the subtitle, rotating long-tail keywords in the 100-char keyword field on iOS. On Google Play, work your keywords naturally into the first 170 characters of the full description, since that's what most heavily influences ranking.
- iOS: name (30) + subtitle (30) + keyword field (100)
- Google Play: title (30) + short desc (80) + full desc (4000, all indexed)
- Primary keyword in title, secondary in subtitle, long-tail rotated
Screenshots and preview video
Screenshots are the single biggest conversion lever in ASO. The first 3 screenshots drive 80% of install decisions. Use them to communicate the core value proposition, not to show UI.
Best practices: consistent visual language across all screenshots, headline text overlaid on each screenshot explaining the benefit, device frame optional (sometimes helps, sometimes hurts — A/B test it), localized versions for major markets, and a 15–30 second app preview video for iOS.
- First 3 screenshots drive 80% of install decisions
- Communicate value, not UI — use overlaid headline text
- Localize for major markets; A/B test device frames
- iOS: include 15–30s app preview video
Reviews and ratings
App rating is the second-biggest conversion factor after screenshots. Apps below 4.0 stars lose roughly 30% of installs vs 4.5+ apps. Prompt for reviews at the right moment (after positive usage events, never during the onboarding funnel), use the native App Store rating prompt (SKStoreReviewController on iOS, in-app review API on Google Play), and always respond to negative reviews within 48 hours.
- Target 4.5+ stars; below 4.0 loses ~30% of installs
- Prompt at positive usage moments, never during onboarding
- Use native rating prompts (SKStoreReviewController, Play in-app review API)
- Respond to negative reviews within 48 hours
Category strategy and ranking
Category choice affects discovery. Pick the category where your app can credibly rank top 100 (ideally top 50). Sometimes a less crowded category is better than a perfect-fit one where you will never rank.
Secondary category (if available) extends your surface area. Use it for an adjacent category where your app is also relevant.
- Pick category where you can credibly rank top 100
- Secondary category extends discovery surface
Ongoing optimization cadence
ASO is an ongoing discipline, not a launch checklist. Monthly cadence: review keyword rankings, A/B test screenshots (Apple Product Page Optimization, Google Play experiments), update description with new features/benefits, monitor review sentiment and respond. Quarterly: refresh screenshots, reconsider keyword mix, audit competitor moves.
Budget: $2k–$8k/month for competent ongoing ASO as a dedicated line item. DIY is possible for early stage but rarely sustained past Series A.
- Monthly: ranking review, A/B tests, description updates, review response
- Quarterly: screenshot refresh, keyword mix audit, competitor review
- Budget: $2k–$8k/month for ongoing ASO
Conclusion
ASO is a discipline, not a launch task. Credible programs drive 30–50% of modern app installs, and the work compounds: good keyword rankings persist, good screenshots get A/B tested into great screenshots, and a 4.5+ rating stays a 4.5+ rating with maintenance. Budget it as a dedicated line item and treat it like the ongoing marketing channel it actually is.