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Sumi on your computer.

The same Sumi you use in the browser, in its own window with a desktop icon. Your books stay safely in Sumi's cloud, so they're the same on your laptop, phone and browser.

Download for WindowsWindows 10 and 11 · 1.1 MBDownload for MacmacOS 10.15 or later (Apple silicon and Intel) · 3.3 MB

Version 1.0.0, built 28 October 2026. Prefer not to install anything? Use Sumi in your browser; it's exactly the same.

Why your computer may show a warning

Sumi is new, and we're in the process of getting our official code-signing certificate from Microsoft and Apple. Until it's in place, Windows and macOS show a caution message for any app they haven't seen before. It's a standard message for new publishers, not a sign that something is wrong. Once our certificate is issued, the warning goes away.

  • Built automatically from our code. Every installer is made by GitHub's build servers straight from Sumi's source code, not on someone's laptop.
  • No admin rights needed on Windows. It installs just for you and can be removed any time from Settings, Apps.
  • Nothing extra on your computer. The app only opens Sumi's own website. Other links open in your normal browser, and the app can't read your files.
  • Same protection as the website. Encrypted connection, your password, and optional login codes by email.
  • You can check the file. Each download has a fingerprint (SHA-256) below. If yours matches, it's exactly the file we published.

Installing on Windows

  1. Click Download for Windows. If your browser says the file “isn't commonly downloaded”, choose Keep (in Edge: the … menu, then Keep).
  2. Open Sumi-Setup.exe.
  3. If a blue box says “Windows protected your PC”, click More info, then Run anyway. It will say “Unknown publisher” until our certificate is issued; that's expected.
  4. Follow the installer. Sumi appears in your Start menu and on your desktop.
Check the file's fingerprint (optional)

SHA-256 of Sumi-Setup.exe:

7e7d0de8d4564d78d5671287307eaecc4244cd89ec98bb8cf1b0bfea21fe7947

To check, run this in Windows PowerShell and compare:

Get-FileHash $HOME\Downloads\Sumi-Setup.exe -Algorithm SHA256

Installing on Mac

  1. Click Download for Mac (choose Intel if your Mac is older than 2020) and open the downloaded file.
  2. Drag Sumi into your Applications folder.
  3. Open Sumi from Applications. If macOS says it can't verify the developer, click Done.
  4. Open System Settings, then Privacy & Security. Scroll down to the message about Sumi and click Open Anyway, then confirm. (On older macOS you can also right-click Sumi and choose Open.)
  5. You only need to do this once.
Check the file's fingerprint (optional)

SHA-256 of Sumi.dmg:

5bb948770dc944d3e601481a66b6622d09b48c6fde7be84443a52d33fc165c40

To check, run this in Terminal and compare:

shasum -a 256 ~/Downloads/Sumi.dmg

Good to know

  • Sumi needs an internet connection. If you're offline, the app waits and reconnects by itself.
  • You sign in with your usual Sumi email and password. Everything you do in the app is saved to the same books as the website.
  • Questions or worries before installing? Email info.intplus@gmail.com and we'll help.