The LexLens app and website share the same content and features, but a few things differ by design.
Billing
Following App Store rules, the iOS app doesn't show web payment links. You upgrade in the app via Apple In-App Purchase, and manage or cancel in your Apple Account (Settings → Subscriptions). On the web, upgrading and billing go through Stripe, managed in Account Settings → Manage Billing. Always manage a subscription where you bought it. See Upgrading to Pro (iOS app).
Sign-in
The app adds Continue with Apple, native Continue with Google, and Face ID sign-in. The web "Continue with Google" redirect and SSO are used on the website.
Navigation
The app has a bottom bar (Home · Explore · Saved · Menu); the Menu tab opens the sidebar. Mobile web uses a top header instead — there's no bottom bar on the mobile website.
Notifications
Push notifications are app-only. Email digests work on both. See Notifications on the iOS app.
Offline
If you go offline while the app is open, it shows "You're offline — showing cached articles" with recent items. Opening the app for the first time with no connection may not load — reconnect and try again.