Selfhosted

In my mind it would be super useful, I could sync my photos when my PC is on and when is off rely on my local photos only since my main goal is having a backup of them.

You could do this perfectly with the docker version, so just curiosity here, why not user docker?

Is it because you don't want to install docker for only Immich? (you could also install other selfhosted server/apps as bonus),

would you be against snap? As someone already mentioned, there is a snap version.

If the important thing is having backups of your photos, there are alternative apps with different packaging formats.

You could make a request for flatpak, and see if other users also would like it, but you would have to wait for feedback from devs and understand if they don't have the resources or willingness to maintain it.

Am I crazy or it makes sense?

If I'm interested in a specific app, I see what packaging formats it has and see how to install it and try it out. Only if I'm having issues with it (that can't be solved), or can't run it on my specific distro with the available packaging formats, I try to suggest/request a different format.

My understanding is that Flatpaks are generally reserved for GUI applications and not command-line tools or servers. I’m not sure it’s the ideal format for Immich.

That said—and I’m probably going to get hate for this—there is an Immich snap package that does just what you’re looking for.

Immich needs an external database.

Jellyfin uses built-in sqlite.

It’s extra work to maintain and test another release format — and the core developers want to focus on making software.

No one is stopping you from rolling your own flatpak.

If your goal is simply having a backup then Immich is probably overkill. Why not just use something like Syncthing?

It probably can be packaged in a flatpak but it would be more of a challenge than using the docker package. You could implement your use case today with the default docker compose setup. You could be up and running in minutes. Start it with -d and it would even start automatically on reboot. It won't consume any more resources than a flatpak version.

Just try this in a directory somewhere: https://immich.app/docs/install/docker-compose/

As for docker itself, if you're on Ubuntu or Debian, you can use the docker version from the stock repos. The package is docker.io and for compose you want docker-compose-v2

I guess I'm a bit confused, immich does have a few docker containers available, I'm using one for backups and it works great.