Kation

Kation is an unofficial Proton Drive client for KDE Plasma. It is not affiliated with or endorsed by Proton AG.

Status: initial release. Sign-in, the online view, folder sync and the Plasma integration are done and tested on a desktop with a real Proton account. See ROADMAP.md for what the initial release includes and ideas for what comes next.

What it does

Kation puts your Proton Drive on your KDE desktop, in two ways:

• Browse it in Dolphin. Proton Drive shows up under Network in Dolphin and in the Open and Save dialogs of your apps. You work directly with the files online, without keeping a copy on your computer.
• Keep a folder in sync. Turn on sync and a Proton Drive folder in your home folder stays the same as your Proton Drive: what you change on one side appears on the other. It works offline and catches up when you are back online.

A tray icon shows whether everything is up to date, and icons in Dolphin show which files are synced. Kation signs you in through Proton's own web page, so it never sees your password.

Sync is careful with your files:

• Nothing is deleted for good: deleted files go to the Proton Drive trash or your computer's Trash.
• If a file was changed in both places, you keep both versions.
• Sync pauses instead of deleting when something looks wrong: many files deleted at once, the sync folder missing (an unplugged disk, say), or a different account.

The details are in How folder sync works.

Installing

Download the package for your distribution from the latest release and install it. Releases after 0.2.0 come with SHA256SUMS and build provenance: check the package you downloaded first (the second command needs the GitHub CLI).

sha256sum -c SHA256SUMS --ignore-missing
gh attestation verify <package file> --repo hleroy/kation \
    --signer-workflow hleroy/kation/.github/workflows/release.yml

sudo apt install ./kation_*_amd64.deb            # Debian 13
sudo dnf install ./kation-*.fc43.x86_64.rpm      # Fedora 43
sudo pacman -U kation-*-x86_64.pkg.tar.zst       # Arch Linux
systemctl --user daemon-reload

Each package is built for that distribution release. On another distribution or release (Ubuntu, KDE neon, …), build Kation from source: see DEVNOTES.md.

There is no Flatpak or Snap: most of Kation runs as plugins inside the system's Dolphin and System Settings, which a sandboxed package cannot provide (see ROADMAP.md).

Using it

1. Enable the Secret Service in KWallet: System Settings → KDE Wallet → "Use KWallet for the Secret Service interface". If another package pulled in GNOME Keyring and it now answers in place of KWallet, scripts/disable-gnome-keyring.sh stops it from starting (nothing is uninstalled; --undo restores it).
2. Start Kation from the application launcher and click Sign In….
3. Open protondrive:/ in Dolphin (or click Open Online View). It is also listed under Network.
4. To sync a folder, click Turn On Sync in the Kation window. The first sync downloads all of "My files", so check your free disk space, or untick big folders in Folders to Sync first.
5. Restart Dolphin once after installing, so it loads the emblems and the Proton Drive context menu.

kationd also has commands for scripts and troubleshooting. They go through the running service, so they never compete with it for the Proton session:

kationd status
kationd ls /Documents
kationd sync            # status; also: on, off, pause, resume, now
kationd sync exclude /Videos   # stop syncing a folder (include, excluded)
kationd sync limits 500 0      # upload limit in KiB/s, no download limit
kationd activity               # what sync did recently
kationd link --create /Docs/report.pdf   # public link (also a local path)
kationd weburl /Docs/report.pdf          # address in the Proton Drive website
kationd login | logout

Add --json for machine-readable output and --verbose to see logs.

What	Where
Session	Your keyring (KWallet), entry com.hleroy.Kation
Encrypted metadata caches	~/.cache/kation
Client ID, event cursors, sync state	~/.local/share/kation
Sync settings and speed limits	~/.config/kation/sync.json
Tray settings	~/.config/kationrc; autostart entry ~/.config/autostart/com.hleroy.Kation.tray.desktop
Logs	~/.local/state/kation/kationd.log

Signing out deletes the session, the caches, the sync state, the log and partial downloads. The files in the sync folder and the settings stay.

Logs stay on your computer; Kation sends no telemetry.

Environment variables for kationd:

• KATION_LOG_LEVEL: DEBUG, INFO (default), WARNING or ERROR.
• KATION_CREDENTIALS_STORE: keychain (default), pass, or unsafe_file (plaintext, for tests only).

Contributing

Building from source, the development setup, tests and releases are described in DEVNOTES.md.

Proton's rules for third-party apps

Proton allows its SDK in personal, non-commercial projects that follow its guidelines. Kation follows them:

• It identifies itself honestly, as external-drive-kation@<version>.
• It only talks to Proton's official servers.
• It uses Drive events rather than polling.
• It uses no Proton logos or branding.
• It states that it is unofficial wherever you sign in.

License

Kation is licensed under GPL-2.0-or-later. Code copied from Proton's SDK repository is MIT licensed. See REUSE.toml and LICENSES.