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Loupe – A iOS app that raises awareness about what native apps can see

read original get Privacy Screen Protector → more articles
Why This Matters

Loupe highlights the often unseen ways iOS apps can fingerprint users through publicly accessible APIs, raising awareness about privacy risks in the mobile ecosystem. By exposing these signals, it empowers consumers and developers to better understand and protect their digital privacy. This tool underscores the importance of transparency and informed decision-making in the ongoing debate over user data security.

Key Takeaways

Loupe

Loupe is an iOS and iPadOS app that gives you a hands-on tour of the device fingerprinting surface. It reads real values from public iOS APIs, the same ones any third-party app can call, and shows them to you raw. The point is simple: see what your iPhone quietly exposes, and why each reading helps an app recognize you again.

Trackers don't need your name, email, or location to recognize you online. Each reading isn't necessarily unique on its own, but together they form a fingerprint that follows you across apps and websites.

How signals are organized

Loupe groups every reading into three tiers, reflecting the cost of access:

Passive — visible to any app with no prompt at all (locale, time zone, screen, battery, and more).

— visible to any app with no prompt at all (locale, time zone, screen, battery, and more). Needs Permission — readings that trigger an iOS prompt (contacts, photos, location, calendars).

— readings that trigger an iOS prompt (contacts, photos, location, calendars). Advanced — clever side-channel uses of public APIs, such as URL-scheme probing via canOpenURL and Keychain persistence across reinstalls.

Privacy

Nothing Loupe reads leaves your device unless you explicitly export it. Values are shown raw, without aggregation or hashing. Nothing is uploaded, synced, or shared.

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