Stop people reading your Mac screen in a cafe

Screen privacy in a cafe starts with where you sit: back to a wall, away from the queue, with no street window behind you. Then turn the brightness down, stop notification previews, and have one quick way to cover the screen when you look away or get up. macOS can lock the screen with Control-Command-Q, and Shoji adds what the lock does not: a blur that keeps only the window you are using sharp, and a cover that comes on by itself when you stop using the Mac.

None of it is complicated, but the order matters. The seat does more than any setting, and the settings do more than any app.

Choose the seat before you open the lid

Your screen faces the same way your back does. Whatever is behind you can see it, so the best seat is the one with nothing behind it.

• Back to a wall. Nobody can stand behind you, and the only angles left are the seats beside you.
• A corner, if there is one. A wall behind and a wall to one side leaves one direction open.
• Not by the queue, the counter or the path to the restrooms. Each person passing only glances for a second, but a steady stream of them adds up to a lot of glances, and people standing in line have nothing to do but look around.
• Not with a street window behind you. Glass works both ways. Someone waiting outside can see a bright screen in a dim room more clearly than you would expect.
• At a long shared table, take the end. The people opposite see the back of your lid. The person beside you sees your screen at an angle for as long as you both sit there.

If the only free seat is a bad one, that is worth knowing too. It is a seat for reading the news, not for the payroll spreadsheet.

Change a few settings before you start

These take a minute and stay set, so you can do them once at home.

1. Turn the brightness down. Use the brightness keys or the Display slider in Control Center. A screen at full brightness in a dim cafe can be read from further away and draws the eye of anyone looking around the room. Go as low as you can comfortably work.
2. Zoom out a step. In Safari, Chrome and most document apps, Command-Minus zooms the content out. Text you can read at arm’s length is harder to read from the next table. Find the size that works for you, and no bigger.
3. Stop notification previews. In System Settings, open Notifications and set Show previews to Never while you are out. A banner then says that Messages has something for you, not what it says. Or turn on Do Not Disturb from Control Center for the session.
4. Close what you will not need. Mail, chat, the banking tab from this morning. Every open window is something that can come to the front when you switch apps.

While you work

The window you are typing in is the one you are watching. If someone leans in, you will probably notice. The rest of the screen is different: the chat in the corner, the email behind your document, the tab you switched away from. That is what a neighbor reads while you are concentrating.

macOS can take those windows away. Hide Others in the app menu (Option-Command-H) hides every app but the one in front, and full screen gives one window a whole Space. Both work, and both mean that switching apps brings a whole app back into view.

Shoji has a mode made for this, called Focus Blur. Only the window you are using stays sharp, the rest softens, and the sharp spot follows you as you switch. You can still see where everything is; the person at the next table cannot read it. Messages, Slack and Mail can also stay blurred unless you are the one using them, and holding Option over one lets you peek.

The cafe moment Focus Blur does not cover is when you stop looking at the screen altogether. A friend arrives, your phone rings, you watch the room for a while. That is what Shoji’s away timers are for. You can have the screen blur after a minute with no input and lock after five, or any timing you like. The timer waits while a video or a call keeps the display awake, so a video call is not blurred in the middle of a sentence.

When you go up to the counter

A lock protects what is on the laptop, not the laptop. If you can carry it to the counter, do. If you leave it, ask someone you came with to watch it.

If it does stay on the table, lock it. Control-Command-Q works, and so does a hot corner set to Lock Screen (in System Settings, under Desktop & Dock, then Hot Corners). If FileVault is on, in System Settings under Privacy & Security, the startup disk is encrypted, so someone who takes the laptop cannot read your files without your password.

Shoji’s own lock is made for these short trips: press Command-L. A screen slides shut over everything, the display stays on, and downloads keep going while you wait for your order. While it is shut, the keyboard belongs to the lock, so anyone tapping keys as they pass reaches nothing. Each wrong password makes the next try wait longer, and you see every failed try when you come back. Touch ID opens it, which matters in a cafe more than most places: a password typed in front of a queue is a password someone can watch (what a watcher can pick up).

The lock can show a clock or a note. In a cafe, skip the note. “Back in five minutes” is helpful on an office desk, and it tells a room full of strangers exactly how long the laptop will be alone.

If the queue is long or you get talking, Shoji turns on the real macOS lock as well after an away time you choose, so a longer absence ends at the full macOS lock screen.

What a cafe setup does not fix

• Cameras. Many cafes have security cameras, and anyone can photograph a screen. Whatever is sharp at that moment is in the picture, and no blur or lock app protects against that.
• The window you are working in. Focus Blur keeps it sharp on purpose, so the person beside you can still read it. Only a physical privacy filter changes the angle a screen can be read from, and software is not a filter.
• Public Wi-Fi. What travels over the network is a separate problem from what is on the screen, and nothing in this guide touches it.
• Theft. See above. Take the laptop with you.

One thing Shoji does not need is access to your screen. The blur is drawn by macOS itself, so it asks for no Screen Recording, Accessibility or Full Disk Access permission, and your password goes straight to macOS, never stored or sent. It costs $14 once, is free for 24 hours, and runs on macOS 14 or later, on Apple silicon and Intel.

Questions

What is the most private seat in a cafe? A seat with your back to a wall, ideally in a corner, away from the counter and the queue. The fewer people who can stand or walk behind you, the less of your screen anyone sees.

Is it safe to leave a locked MacBook on the table? A locked Mac keeps people out of your apps, and FileVault keeps the disk unreadable without your password. Neither stops someone picking the laptop up. Take it with you when you can.

Does turning down the brightness really help? It does not stop someone sitting right beside you from reading the screen. It does make the screen harder to read from across the room, and it catches fewer eyes.