Gentle reminders to blink, so your eyes don't dry out while you work.
When you stare at a screen, you blink far less than normal. A healthy rate is about 15 to 20 times a minute, but while focusing it can drop to just 4 or 5, which leaves your eyes dry, tired, and sore. Blink watches how often you blink and gives you a soft nudge on screen when it's been too long. No pop-ups. The design follows research (the 2014 "Stimulating a Blink" study from UC Davis): gentle on-screen cues get people to blink more, a soft screen blur works best, and pop-ups are the worst because people just turn them off. The cues fade in and out slowly, so you notice them out of the corner of your eye without being pulled away from what you're doing.
Blink is private by design, and you can check that for yourself:
- It doesn't send or receive any data over the network. No accounts, analytics, updater,
or crash reporting. A built-in kill-switch cancels outbound requests, and Chromium's
background networking is disabled. (Choosing "Support Blink" opens a link in your own
browser.) You can confirm it with a tool like Little Snitch or
nettop: nothing goes out. - The webcam is optional and off by default. Blink works fine on a simple timer with no camera. You only turn the camera on if you want to.
- Camera video never gets saved or sent. In webcam mode, each frame is checked in memory and thrown away right after. Nothing is recorded, shown, or sent anywhere. Only simple facts are used, like "a blink just happened".
- Your settings and stats stay on your Mac. They live in one plain text file. You can open its folder, export it, or delete everything from Settings.
- No account, no cloud, no tracking.
Blink can run in two ways:
| Mode | What it does | Camera |
|---|---|---|
| Timer (default) | Reminds you on a set schedule | Not used |
| Webcam (optional) | Only reminds you when you actually stop blinking, using on-device face tracking | On-device only |
And it can remind you in three ways. You pick your favorite during the quick first-time setup, or later in Settings:
- Blur: a soft, frosted pulse (the one the research liked best).
- Dim: the screen gently darkens, then comes back.
- Glow: a soft glow breathes around the edges of the screen (you can pick the color).
A menu-bar desktop app built with Electron, TypeScript, and electron-vite, with on-device face tracking from MediaPipe and unit tests in Vitest.
Some of the more interesting parts of the code:
- Privacy is enforced in code, not just promised. The main process installs a network kill-switch that cancels every outbound request except local files, and disables Chromium's background networking, so the "no network" claim is something you can actually verify. Camera frames never leave the hidden detector window; only small facts (a blink happened, the current blink rate) are passed to the rest of the app.
- On-device blink detection. A hidden window runs MediaPipe's Face Landmarker at about
10 frames per second and reads the eye-blink signals. The model and its WebAssembly files
are bundled with the app and served from a custom local
app://protocol, so nothing is ever downloaded at runtime. - Works with no camera. Timer mode is the default and needs no permission. Webcam mode falls back to the timer automatically if the camera is denied or busy, and pauses itself when it can't see a face.
- Ambient overlays. The cues render in a transparent, click-through, always-on-top window, one per display, with a smooth fade in, short hold, and fade out.
- A real macOS frost option. An optional blur that uses a genuine macOS vibrancy layer (NSVisualEffectView) to blur the desktop behind the cue, crossfaded in and out.
- The tricky logic is pure and tested. The blink math (eye aspect ratio, blinks per minute, and the rules for when to remind you) lives in plain TypeScript with no Electron code, covered by unit tests.
src/
├─ main/ app startup, menu bar, overlays, detection, permissions, storage
├─ preload/ small safe bridges between the app and each window
├─ renderer/
│ ├─ overlay/ the full-screen reminder layers
│ ├─ detector/ hidden window that reads the webcam (only when turned on)
│ └─ settings/ first-time setup and the settings window
└─ shared/ plain, tested logic with no Electron code
├─ cue-timing.ts the fade in and fade out timing
├─ ear.ts measuring the eyes and spotting blinks
├─ bpm.ts blinks per minute
└─ trigger.ts when to show a reminder
One thing worth knowing about the overlay: it sits on top of normal apps and video, but a true full-screen Mac app (on its own Space) can cover it up. That is a limit of macOS.
Blink is built for macOS first. The code is kept tidy so Windows and Linux can come later.
If Blink helps keep your eyes comfortable, you can support its development on Ko-fi: ko-fi.com/rezasoleimani. It's entirely optional and the app makes no network calls of its own.