When starting niri from a display manager like GDM, or otherwise through the niri-session binary, it runs as a systemd service. This provides the necessary systemd integration to run programs like mako and services like xdg-desktop-portal bound to the graphical session.

Here's an example on how you might set up mako, waybar, swaybg and swayidle to run as systemd services with niri. Unlike spawn-at-startup, this lets you easily monitor their status and output, and restart or reload them.

1. Install them, i.e. sudo dnf install mako waybar swaybg swayidle

2. mako and waybar provide systemd units out of the box, so you can simply add them to the niri session:

   systemctl --user add-wants niri.service mako.service
   systemctl --user add-wants niri.service waybar.service
   

   This will create links in ~/.config/systemd/user/niri.service.wants/, a special systemd folder for services that need to start together with niri.service.

3. swaybg does not provide a systemd unit, since you need to pass the background image as a command-line argument. So we will make our own. Create ~/.config/systemd/user/swaybg.service with the following contents:

   [Unit]
   PartOf=graphical-session.target
   After=graphical-session.target
   Requisite=graphical-session.target
   
   [Service]
   ExecStart=/usr/bin/swaybg -m fill -i "%h/Pictures/LakeSide.png"
   Restart=on-failure
   

   Replace the image path with the one you want. %h is expanded to your home directory.

   After editing swaybg.service, run systemctl --user daemon-reload so systemd picks up the changes in the file.

   Now, add it to the niri session:

   systemctl --user add-wants niri.service swaybg.service
   

4. swayidle similarly does not provide a service, so we will also make our own. Create ~/.config/systemd/user/swayidle.service with the following contents:

   [Unit]
   PartOf=graphical-session.target
   After=graphical-session.target
   Requisite=graphical-session.target
   
   [Service]
   ExecStart=/usr/bin/swayidle -w timeout 601 'niri msg action power-off-monitors' timeout 600 'swaylock -f' before-sleep 'swaylock -f'
   Restart=on-failure
   

   Then, run systemctl --user daemon-reload and add it to the niri session:

   systemctl --user add-wants niri.service swayidle.service
   

That's it! Now these three utilities will be started together with the niri session and stopped when it exits. You can also restart them with a command like systemctl --user restart waybar.service, for example after editing their config files.

To remove a service from niri startup, remove its symbolic link from ~/.config/systemd/user/niri.service.wants/. Then, run systemctl --user daemon-reload.

Running Programs Across Logout

When running niri as a session, exiting it (logging out) will kill all programs that you've started within. However, sometimes you want a program, like tmux, dtach or similar, to persist in this case. To do this, run it in a transient systemd scope:

systemd-run --user --scope tmux new-session