Definition
Install velocity is the rate at which new merchants install an app over a rolling window — typically expressed as installs per day, week, or month. On Shopify, install velocity is widely understood as the single strongest signal feeding the App Store's ranking algorithm: a sharp acceleration in the trailing 7-30 day window typically translates to category-position climbs within 1-2 ranking cycles. Atlassian, WordPress, and Zendesk apply similar velocity weighting, though with different lookback windows and smoothing functions that the marketplaces don't publish. Install velocity is distinct from total active installs — a mature app with 50,000 active installs and zero weekly velocity is stable but stagnant; a 6-month-old app at 2,000 installs adding 150 per week is gaining ground. AppRanks does not compute install velocity directly because most marketplaces don't expose per-day install counts publicly; we infer momentum from category-position trajectory and review-velocity correlation.
Where you see it on AppRanks: App page "Category Rankings" trajectory, audit page "Adoption" check.
Why this metric matters
Install velocity is the single most diagnostic short-term momentum signal for a marketplace app — it leads category-position changes by 1-2 ranking cycles, so an acceleration usually shows up in install counts before it shows up in headline ranking. For developers running campaigns, comparing velocity in the trailing 7 days against a 30-day baseline reads whether the campaign moved real merchants or just generated impressions. For competitive intelligence, a competitor's velocity step-change typically precedes a feature launch, pricing change, or marketplace promotion worth investigating; spotting it early gives a 2-3 week window to respond before the install gap compounds through ranking.
How AppRanks computes it
Marketplaces don't expose per-day install counts publicly, so AppRanks infers install velocity rather than measuring it directly. We scrape category leaderboard positions and review-velocity signals on a 12-24 hour refresh cycle; sustained position climbs combined with positive review velocity correlate tightly with real install acceleration. When Shopify or Atlassian publishes a public install count on the listing (Cloud Fortified apps, BFS-badged apps), we diff the count across snapshots and surface the implied weekly run-rate. For most apps the install count itself is not public; the public app page then surfaces the category-position trajectory and v7d/v30d/v90d review windows as the available proxy signals.
Use cases
- Launch attribution: comparing v7d after a marketing push against the 30-day baseline isolates whether the campaign moved real installs or just generated marketplace impressions.
- Competitive watch: a competitor's velocity step-change typically precedes a feature or pricing announcement; spotting it 1-2 weeks early gives time to respond before ranking compounds.
See also: Active installs — the running total install velocity feeds · Marketplace ranking — what install velocity drives · Example audit with adoption signals
External references: Shopify App Store ranking factors (official docs)