Bluesky hijacks an iOS privacy API to stamp its logo on your screenshots

A user noticed that screenshots of Bluesky posts carry the app’s butterfly logo in the corner — even though the live app shows a “Follow” button in that exact spot, with no logo visible. Because Bluesky’s client is open source, the mechanism was easy to trace: a component added in January 2026 (in a file named GrowthHack.tsx) leans on the app’s expo-privacy-sensitive package to pull off the swap.

The technique repurposes iOS’s secure-text-entry feature. The package renders the Follow button into the layer of a UITextField that has isSecureTextEntry set to true. When the system captures a screenshot, iOS deliberately blanks that field’s layer to protect sensitive input — which erases the button and exposes the Bluesky logo sitting underneath. The effect only fires on true screenshots: during an app-switch gesture, iOS grabs its own snapshot before the blanking kicks in, so the swap never happens. On non-Apple platforms the content just renders normally, with no masking.

The trick isn’t novel — Signal and Telegram use the same secure-field blanking to shield their private chats, so Apple is unlikely to close it off. What’s notable is the intent: a privacy primitive is being turned into a growth/branding lever, watermarking shared content with the app’s identity. Reaction on the pull request was mostly negative before the thread was locked, underscoring the tension between a clever hack and misusing an API meant to protect users.