Caffeine Applet for COSMIC DE

A third-party applet for the COSMIC desktop that prevents your system from going idle. Not official COSMIC software and not endorsed by System76. Left-click the coffee icon to toggle an inhibit lock that blocks idle and sleep, keeping your screen on and your machine awake. Right-click for a menu to inhibit for a set time.

Uses the logind D-Bus Inhibit interface directly — no child processes, no PID files, crash-safe by design. Works on any system running systemd-logind or elogind.

Features

• Left-click toggle: Left-click the panel icon to start the configured default idle/sleep session, or end the current session. The default is indefinite. The closed-lid switch is independent.
• Optional closed-lid control: Opt in through the settings file to reveal a Keep awake with lid closed switch. It starts off on each launch and is independent of timed sessions. Acquisition errors appear in the popup.
• Timed sessions: Right-click to select a duration or run indefinitely. The selected row is highlighted and shows a live countdown, for example 15 minutes — 13 min left. Duration presets are configurable.
• Status icon: The panel icon reflects the current state, a steaming cup when active and an empty cup when idle.
• Auto-expiry: Timed sessions release the inhibit lock on their own when time's up — no need to remember to turn it off.
• Crash-safe: Uses a file descriptor–based inhibit lock. If the applet crashes, the OS automatically releases the lock.
• Minimal: No background processes, no polling, near-zero resource usage.
• Distro-agnostic: Works with systemd-logind and elogind.

Installation

Flatpak (recommended)

Available via System76's official COSMIC Flatpak repository (not Flathub — this applet doesn't have a standalone window/use outside a panel, which is outside Flathub's scope).

flatpak remote-add --if-not-exists --user cosmic https://apt.pop-os.org/cosmic/cosmic.flatpakrepo
flatpak install --user cosmic com.github.codevardhan.caffeine-applet

If you have COSMIC Store installed, it should also be visible there under the COSMIC Applets category, provided you have both the flathub and cosmic remotes added at user scope. System-scope remotes currently don't surface applets correctly in COSMIC Store (pop-os/cosmic-store#477), so if it isn't showing up, add both as --user remotes and it should appear.

From source

A justfile is included for the casey/just command runner.

git clone https://github.com/codevardhan/caffeine-applet.git
cd caffeine-applet
just build-release
sudo just install

Then add the applet to a panel in Settings → Desktop → Panel → Configure panel applets.

Uninstall

# Flatpak
flatpak uninstall --user com.github.codevardhan.caffeine-applet

# Native
sudo just uninstall
# or manually:
sudo rm /usr/bin/caffeine-applet
sudo rm /usr/share/applications/com.github.codevardhan.caffeine-applet.desktop
sudo rm /usr/share/icons/hicolor/scalable/apps/com.github.codevardhan.caffeine-applet*.svg
sudo rm /usr/share/metainfo/com.github.codevardhan.caffeine-applet.metainfo.xml

Log out and back in for COSMIC settings to update.

Packaging

If packaging for a Linux distribution, vendor dependencies locally and build with vendored sources:

just vendor
just build-vendored
just rootdir=debian/caffeine-applet prefix=/usr install

Translators

Fluent is used for localization. Translation files are in the i18n directory. New translations may copy the English (en) localization, rename en to the desired ISO 639-1 language code, and provide translations for each message identifier.

Contributing

Contributions are welcome! Feel free to open an issue or submit a pull request. For major changes, please open an issue first to discuss what you would like to change.

Settings

On first launch the applet creates a commented RON settings file from the shipped template at:

~/.config/cosmic/com.github.codevardhan.caffeine-applet/v1/settings

It respects XDG_CONFIG_HOME. For Flatpak, the file is normally under ~/.var/app/com.github.codevardhan.caffeine-applet/config/cosmic/com.github.codevardhan.caffeine-applet/v1/settings.

(
    duration_minutes: [15, 30, 60],
    default_duration_minutes: None,
    dangerous_enable_closed_lid_control: false,
)

The generated file explains units, valid values, examples, left-click behavior, the closed-lid opt-in, and when changes apply. Existing settings and comments are preserved; updates do not replace your file.

Edit duration_minutes to choose your presets, for example [10, 25, 50, 90]. Use one to eight unique, positive whole-minute values, in the desired menu order. Indefinitely is always available. Reopen the popup to reload file changes; existing timers continue with their original deadline. If you remove a running duration from the presets, its countdown stays visible until that session ends. Invalid files produce a popup error and keep the last valid settings (or defaults at startup); the applet does not overwrite them.

default_duration_minutes selects the session started by left-clicking the panel icon. None preserves indefinite sessions; Some(25) starts a 25-minute session. Use positive whole minutes. It may be a duration outside the preset list; its active countdown will still appear. Explicit menu choices always use the duration you select. Settings are also reloaded before starting a session with left-click.

dangerous_enable_closed_lid_control gates availability, not activation. It defaults to false, hiding the lid switch. Setting it to true reveals the switch but never starts a lid inhibitor automatically. The switch is a session control and is not saved; every applet launch starts it off. Setting the config flag back to false releases any active lid inhibitor on the next settings reload. Opt in deliberately for your hardware and cooling setup.

How a session keeps the system awake

Starting a session acquires two inhibitors together, and ending one releases both:

• logind — org.freedesktop.login1.Manager.Inhibit with idle:sleep in block mode. Portable, and it blocks suspend requested from elsewhere. Required: if this cannot be acquired the session does not start.
• Screensaver — org.freedesktop.ScreenSaver.Inhibit on the session bus. On COSMIC this is the one that actually stops the screen blanking. cosmic-idle drives screen-off, auto-lock and auto-suspend, and it does not read logind inhibitors at all, so the logind lock alone leaves the display blanking on schedule. Optional: desktops that do not offer the interface still get a logind-only session, and the popup says so.

If the screensaver inhibitor could not be acquired, the popup shows "Session started, but the screen may still blank". Recover by ending the session and starting it again.

The screensaver inhibitor is held by a dedicated D-Bus connection. It is released explicitly on exit, and closing the connection releases it even if the applet is killed outright.

Closed-lid behavior

When the optional switch is on, it uses the same org.freedesktop.login1.Manager.Inhibit interface as ordinary Caffeine sessions, with sleep:handle-lid-switch in block mode. The low-level lid inhibitor matters because logind ignores ordinary sleep inhibitors for lid events by default. This works with systemd-logind or elogind; the service's authorization policy still applies. Other power managers that handle lid events themselves may require their own configuration. The switch reports whether its inhibitor was acquired; hardware suspend behavior still needs to be verified. The display may still blank when only this switch is enabled.

See systemd's inhibitor documentation.

License

MIT