Choosing an iOS app development company is a test of platform depth rather than portfolio size. Ask about Swift and SwiftUI experience, the App Store review record, Apple ecosystem work, who owns the code and accounts, and the post-launch model.
Platform depth, not app count. Ask what proportion of the firm's work is native Swift and SwiftUI, how they handle the major iOS release Apple ships every September, and whether they have built against new Apple frameworks in the season those frameworks launched. A studio that mainly ships cross-platform builds is a different proposition to a native iOS team, and neither is wrong provided you know which one you are hiring.
App Store record. Ask for their first-time approval rate across submissions, then ask about the most recent rejection they received and what caused it. A firm that cannot describe a rejection has either submitted very few apps or is not being candid. Ask who pays for remediation and resubmission when it happens, because every round trip costs a launch window.
Ecosystem scope. If Apple Watch, iPad, Apple TV, CarPlay or home screen widgets matter to your product, ask to see shipped examples on those targets specifically. Each is a separate build with its own design language, interaction model and testing, and iPhone experience does not transfer to them automatically.
Ownership. Confirm that the source code, the Apple Developer Program account and the cloud infrastructure are all in your name and that intellectual property transfers to you. The Apple Developer account in particular should never sit with an agency, because recovering an app listing from a supplier you have parted with is slow and sometimes impossible.
What happens after launch. iOS changes every year whether or not you touch the app, and Apple periodically raises the minimum SDK required for submission. Ask for the maintenance model priced and written down, and ask to see an iOS product the firm built and still operates.
For reference, PixelForce builds native iOS in Swift and SwiftUI with 100% in-house development from an Adelaide headquarters, holds a 98 percent first-time app store approval rate across 100+ submissions, has been recognised by Apple with Best of Developers and with Watch and TV App of the Year, and hosts client platforms on the client's own AWS account with the intellectual property transferring to them.