Install the server

Pick your platform and get the free Aardy server running. Downloads are on the Download page.

macOS

Open the downloaded disk image and drag Aardy to Applications, then launch it. Aardy is a menu-bar app — it has no Dock icon. The first time you open it, macOS confirms it's notarized by Apple.

Click the Aardy icon in the menu bar to see:

A status line for each paired Apple TV, with Start on / Stop on to start or stop the screensaver on that TV.
Pair a new Apple TV… — see Pair an Apple TV.
Open Aardy Photo Server… — opens the web admin in your browser.
Server Settings…
Start at Login — tick it to start Aardy whenever you log in.
Share with All Users on This Mac… (or Stop Sharing with Other Users… once shared) — see below.
About Aardy… and Quit Aardy Photo Server.

If the menu-bar icon is hidden (for example, under the notch on a MacBook), Aardy opens the web admin in your browser instead.

Share with all users on this Mac

If several people log in to the same Mac, choose Share with All Users on This Mac… so the Apple TVs keep playing no matter who is logged in.

You're asked for an administrator name and password once. Aardy restarts once to finish setting up.
From then on Aardy starts for whoever logs in to the Mac. One user's copy serves the TVs at a time; the others wait in the menu bar and show "Aardy is serving from <user>'s session". If that user logs out, the next logged-in user takes over within about 5 seconds.
The library moves to /Users/Shared/Aardvark ScreenSaver so every user sees the same photos, packs, and pairings.
Users who are already logged in pick it up at their next login.
Network drives and folder permissions belong to whoever is logged in. A source folder that only another user's session can see shows an Unreachable badge on Source Folders and its imports pause; photos already imported keep playing.
Stop Sharing with Other Users… reverses it. The library stays where it is.

Windows

Coming with the public release. The Windows build isn't available yet; this is how it will install.

Run Aardvark-Server.msi. It installs as a background service that starts with Windows. When prompted, allow it through Windows Firewall on private networks (this opens TCP 8737 and UDP 5353 so your Apple TV can find it).

Linux

Coming with the public release. The Linux packages aren't available yet; this is how they will install.

Install the package with sudo apt install ./aardvark-server.deb (or rpm -i). Enable and start it with:

sudo systemctl enable --now aardvark-server

NAS / Docker

Coming with the public release. The Docker image isn't available yet; this is how it will run.

Copy the docker-compose.yml from the download page, set the volume that points at your photos, and run:

docker compose up -d

Use network_mode: host so your Apple TV can discover it via Bonjour.

Once it's running, the server advertises itself on your network under the computer's own name and serves its web admin at http://localhost:8737/ (or http://<this-computer's-ip>:8737/ from another device). On macOS your photo library lives in ~/Pictures/Aardvark ScreenSaver by default.