App Store Metadataとは？

Metadata optimization is the text-based pillar of ASO, complementing the visual pillar of screenshot and icon optimization. Each metadata field serves a different purpose and carries different weight in the ranking algorithms.

On the Apple App Store, the title (30 characters max) carries the most ranking weight and is the most visible text element. The subtitle (30 characters) appears directly below the title in search results and carries significant ranking weight. The keyword field (100 characters) is hidden from users but fully indexed for search. The description (4000 characters) is not indexed for search on iOS but influences user conversion decisions. Promotional text (170 characters) appears at the top of the description and can be updated without a new app version.

On Google Play, the title (50 characters), short description (80 characters), and full description (4000 characters) are all indexed for search. This means keyword placement in the description directly impacts Android rankings. Google Play does not have a separate keyword field.

Optimization tips across both platforms: front-load your most important keywords in the title, use the subtitle or short description for secondary keywords, avoid keyword repetition across fields (the algorithm handles this), write descriptions for humans first and algorithms second, and update your metadata every 4-8 weeks to test new keyword combinations and respond to seasonal trends. Localization of metadata for each target market is also critical, as direct translations rarely capture local search behavior.