With recent developments in legislation around the App Store, you can link users in the United States
You can use Paddle to build a seamless purchase workflow for your iOS app that lets customers make purchases outside your app.
Link out to a checkout that's fully hosted by Paddle to let users make in-app purchases.
Deploy a checkout to Vercel, then link out to it to let users make in-app purchases.
Build your own checkout implementation for more control over the purchase workflow.