Technical and visual guidelines that define how app assets (screenshots, icons, previews) must be formatted, sized, and structured for each app store. Adhering to specifications ensures assets display correctly, maintain quality, and comply with store requirements.
What It Is
Design specifications are the mandatory requirements set by app stores for all visual and creative assets. They cover:
- Dimensions & resolution – exact pixel sizes, aspect ratios, and DPI requirements
- File formats – accepted formats (PNG, JPG, HEIC, MP4, etc.)
- Color space – RGB vs. CMYK, color profile standards
- Safe zones – text and critical imagery placement areas
- Duration & frame rates – for preview videos and animations
- Localization constraints – text length limits, character encoding
Why It Matters for ASO
Compliance with design specifications directly affects:
- Store approval – rejected assets delay or prevent app listing
- Visual presentation – improperly sized assets appear cropped, blurry, or misaligned
- User experience – correct formatting ensures assets render consistently across devices
- A/B testing – baseline compliance is required before running creative experiments
- Localization quality – text specifications prevent truncation in translated versions
Non-compliant submissions are often rejected without publication, requiring resubmission cycles and delaying updates to screenshots, icons, and preview videos.
Key Things to Know
- Both Apple App Store and Google Play Console publish detailed specification documents that update periodically—check before each submission
- Screenshots typically require 9:16 or 16:9 aspect ratios; iPad and watch versions have separate specs
- App preview videos (iOS) and demo videos (Android) have strict length limits (typically 15–30 seconds)
- Icon specifications are especially strict: exact pixel dimensions, no transparent areas, specific margin requirements
- Localized metadata (title, subtitle, description) have character limits that vary by field and store
- Design tool templates from stores or third-party vendors can speed up asset creation while ensuring compliance
- Regenerating assets at lower specifications (e.g., downscaling high-res screenshots) often results in quality loss—design at native resolution