installing katto

safe to open, and here's how to check

Katto is a small app made by one person and one cat. Because it's new, your computer may ask "are you sure?" the first time. That's normal, and this page walks you through it.

no AI inside no accounts we store nothing, it all stays on your desktop no admin password on Windows

why does my computer ask "are you sure?"

Windows and macOS are careful with apps they haven't seen many times before. Big companies pay for a certificate that tells your computer who made the app, and after enough people download it, the warning goes away by itself.

Katto is still new, so the warning shows up. It doesn't mean anything was found. Signed builds are on the way: once Katto has its certificates, Windows and macOS will name the maker and the warning will stop.

Your antivirus may ask the same question for the same reason. If it offers to scan the file, go ahead: that's exactly what it's for.

Windows 10 & 11

  1. Download the installer from your chest. It's called Katto-Setup.exe.
  2. Open it from your Downloads folder (or the browser's download bar).
  3. If a blue box says Windows protected your PC, click More info. Check the app is called Katto-Setup, then click Run anyway.
  4. Katto installs itself in a few seconds, just for you. There's no wizard and no admin password.
  5. The cat appears on your desktop. Click it to open your day, or right-click for settings.

Katto starts with Windows from then on and updates itself quietly. To remove it: Settings › Apps › Installed apps › Katto › Uninstall. It takes its hooks out of your tools on the way.

macOS 12 and newer

  1. Download the disk image from your chest: Katto.dmg. It works on Apple silicon and Intel Macs.
  2. Open it and drag the cat into the Applications folder.
  3. Open Katto from Applications. If macOS says it can't check the app:
    • macOS 15 and newer: click Done, open System Settings › Privacy & Security, scroll down and click Open Anyway next to Katto, then confirm.
    • macOS 12 to 14: Control-click (or right-click) Katto in Applications, choose Open, then Open again.
  4. You only do this once. After that Katto opens like any other app.
  5. Katto may ask for a few permissions, like seeing key presses for the typewriter or your Downloads folder for tidying. You can say no to any of them; that one feature just stays asleep.

Katto updates itself quietly. To remove it, quit Katto from its menu and drag it from Applications to the Bin.

check it yourself

Every Katto download has a fingerprint (a SHA-256 checksum). If the fingerprint of the file you downloaded matches the one below, it's exactly the file we published, byte for byte.

looking up the newest version…

on Windows (PowerShell, in your Downloads folder)Get-FileHash .\Katto-Setup.exe
on macOS (Terminal)shasum -a 256 ~/Downloads/Katto.dmg

Each release is also scanned by around 70 antivirus engines on VirusTotal. The "scan report" links above open the report for that exact file.

what katto does, and doesn't do

doeskeep your list, reminders, notes and settings in a folder on your computer
doesask a weather service for the forecast near a place you pick, and check for updates
doeswork offline for everything else, files and screenshots included
doesn'tuse AI, upload your files, read your screen for anyone, or show ads
doesn'tneed an account, or keep anything about you on our side
doesn'tmake you keep it: uninstalling cleans up after itself

Still unsure about something? Write to hello@thekatto.app. Amazing Man answers (Toby, his Katto, supervises).

privacy · ← back to the cat