How Bluesky draws its logo on screenshots
- ID
- 15057
- Status
- summarized
- Published
- 18 Aug 2026, 6:20 AM
- Fetched
- 20 Aug 2026, 7:09 AM
- Provider
- Hacker News
- Category
- dev-community
- Original URL
- https://timmarinin.net/2026/bluesky-screenshots/
- Source URL
- https://hnrss.org/best
Summary
- Score
- 4.5
- Created
- 20 Aug 2026, 8:13 AM
- Tags
- Audience
- developers
What happened
Bluesky's iOS app hides its logo during normal use and only reveals it on screenshots by rendering the 'Follow' button inside a UITextField with isSecureTextEntry set to true, leveraging iOS's screenshot-blanking behavior for secure fields. The implementation lives in a file called GrowthHack.tsx, introduced in January 2026 by mozzius, using their own expo-privacy-sensitive package. The logo is always present underneath; iOS blanks the secure field layer on screenshot capture, exposing the logo.
Why it matters
If you build mobile apps and want to watermark screenshots or hide sensitive UI elements on capture, this is a concrete, copyable technique using a documented iOS privacy API. The author notes Telegram and Signal use the same approach for secret chats, so Apple is unlikely to patch it. The community debate over whether this is 'cute' or 'abuse of a privacy API' is worth knowing before you adopt it.
Discussion angle
Is repurposing isSecureTextEntry for branding/watermarking an acceptable hack or an abuse of a privacy-sensitive API—and would you ship it in your own app?