What category does
Category determines the top-charts your app appears in, the algorithmic peer set for ranking normalisation, the editorial team that considers you for featuring, and the category-carousel real estate you compete for.
The competitive-density trap
Highest-volume categories (Games, Entertainment) have the lowest per-app visibility. Mid-density categories (Productivity, Health & Fitness) usually offer better rank-to-install economics for mid-market apps.
Primary vs secondary
Apple allows one primary + one secondary. Primary drives most of the algorithmic effect; secondary adds visibility in browse. Play uses one primary + tags, tag selection matters more than teams assume.
Featuring odds
Editorial teams organise by category. If your app genuinely fits a less crowded category, its discoverability may improve. Measure any category switch against a documented baseline.
When to switch
Only when: your product's dominant use case has drifted; a lower-density category is a legitimate fit; you're preparing a major product change that changes the category story. Never for hack-the-charts reasons, Apple and Google both notice and punish category-gaming.