App Store Connect is Apple's set of web tools, also available as an iPhone and iPad app, for developers who publish on the App Store. Members of the Apple Developer Program use it to upload builds, write the App Store product page in up to 40 languages, set up in-app purchases and subscriptions, invite beta testers with TestFlight, submit apps to App Review and reply to customer reviews.
Its Analytics section measures acquisition, engagement and monetization with data that only Apple has. It shows total downloads by territory, device and source (App Store search, browse, referrers), and the conversion rate, the ratio of downloads to unique impressions of the app on the store. Cohort reports follow groups of users over time, and peer group benchmarks compare an app with similar apps. Sales and Trends gives next-day sales and unit data, and Payments and Financial Reports show earnings and taxes.
It is a hosted service included with the paid Apple Developer Program membership.