Komga on a Seedbox: Your Library Is Read-Only, and That's the Right Call

Komga reads your library. It never writes to it.

Komga is a server for comics, manga, magazines and ebooks. You point it at a folder, it builds a browsable library with covers, series, read progress and full-text search, and you read in a browser or in a Kobo, KOReader or OPDS client. It does not download anything. It does not rename anything. It reads.

On an appbox that last part is enforced rather than implied. Our install mounts your library into the container read-only, and that single flag decides which half of Komga's feature list you get. Nobody writes that down before you install it, so you find out when a button fails.

This guide covers the read-only mount and what it rules out, the paths you actually type into Komga, the login that catches everyone, the memory ceiling, and which of the reader apps in our catalogue to use when Komga is the wrong one.

What the read-only mount rules out

Three folders go into the container, all of them read-only:

Everything Komga owns goes to /config, which maps to ~/.config/komga and is writable. That is where the database, the thumbnails, the metadata you edit and the logs live.

So Komga can read every byte of your library and change none of it. What you keep:

• Libraries, series, collections, read lists, read progress
• Metadata editing, including covers and series details, all stored in Komga's own database rather than written back to your files
• Full-text search, duplicate-page detection, one-shots, per-library file-type filters and directory exclusions
• OPDS, Kobo Sync and KOReader Sync

What you lose, and these are the two that produce a support ticket:

• Import Books. Komga's Import screen scans a folder outside your libraries and then moves or hardlinks the files into a destination series. Both of those write. On an appbox it cannot work, and the honest answer is that you should not want it to: the apps that file your books are better at it, and they log what they did.
• Deleting a duplicate file from the Duplicate Files screen. The detection works, because hashing only reads. The trashcan does not, because deleting writes.

If you were counting on either, the thing to change is which app does the filing, not the mount. The mount is read-only because Komga runs as container-root, does not honour PUID/PGID, and rootless Docker remaps that back onto your account. Keeping the library read-only means a scan bug, a bad metadata write or a mis-clicked delete cannot reach the only copy of a 2 TB collection. I would rather explain the missing button.

The paths inside Komga are not the paths you SFTP to

When you click Browse to pick a library root, Komga shows you its own filesystem. You will see /data, /downloads and maybe /flexdisk. You will not see /home/USERNAME/media, because from inside the container that path does not exist.

So if your comics are at ~/media/comics, the library root you type is /data/comics. If your ebooks are at ~/media/books, it is /data/books.

Two rules worth knowing before you add the second library:

• Roots cannot overlap. If you add one library at /data, you cannot add another at /data/comics, because the paths share a prefix. Pick the narrow folders, not /data. One library per content type is also how the file-type filters earn their keep: comics as cbz, cbr, zip, rar, ebooks as epub and pdf.
• Anything outside those three mounts is invisible. The commonest version of "Komga can't see my files" is a library sitting in ~/torrents/data, which is not mounted. Move it under ~/media, or add it to the folder your downloader files into.

~/downloads is mounted on purpose, so you can build a library off freshly grabbed files that are not organised yet. Treat it as a staging view, not a home.

You log in with an email address

Komga has no concept of a username. The account is an email address, and our install creates the first admin for you at install time by calling Komga's own claim endpoint, the same one its setup screen uses.

That admin is [email protected], where USERNAME is your appbox login, with a generated password. Both are in the panel next to the app. If you are typing your appbox username into the login box and getting nowhere, that is why.

One more thing about that login, and it is the reason to change the password: Komga sits on its own subdomain, komga.USERNAME.SERVER, and unlike Calibre and BookLore on the same box it is not behind an appbox login prompt as well. Komga's own login screen is the only thing between the internet and your library. Change the generated password to something you chose, and if you add readers for the household, give them user accounts rather than the admin one. Komga's per-library access restrictions are per user, so a child account can see the comics library and not the rest.

The first scan, and the 1 GB heap

Komga runs on the JVM, and we cap its heap at 1 GB so a thumbnail pass on a big library cannot take the rest of your slice down with it. That is the right trade on shared hardware, and it has one visible consequence: the first scan of a large collection is slower than it would be on a machine with nothing else to do.

Let it finish. The yellow progress bar under the logo shows what is running, and hovering it lists the pending tasks. After the first pass, set a scan interval that matches how often books actually arrive. Hourly is fine for an active automation setup; weekly is plenty for a collection you add to by hand. Leaving it on a tight interval forever just burns I/O re-checking files that have not changed.

Komga's own FAQ warns that the memory figure your operating system reports for a JVM app is not the real usage. If you are looking at the panel's memory graph and worrying, that is the effect, not a leak.

Which reader app to actually install

We list several ways to read books and comics, and they are not interchangeable. The split that matters is whether the app writes to your library:

If you want one sentence: Komga is the reading room, Calibre Web Automated is the door. They are happy together, because CWA files into ~/media/calibre and Komga sees that same folder as /data/calibre. Install both, let CWA do the ingest and conversion, and point a Komga library at the result. That combination gives you the writing you lost without giving Komga write access to anything.

For the grabbing, Komga is not in the conversation. Kapowarr searches and organises comics into volumes, Mylar does the same job the older way, and Shelfmark and Bindery handle ebooks and audiobooks, with Bindery being the modern answer now that Readarr is retired. Any of them can file into ~/media, and Komga picks it up on the next scan. That is the whole pipeline: a downloader writes, Komga reads.

If you are weighing Komga against the lighter option, the Ubooquity guide covers that side. And for audio, which Komga will not touch, see Audiobookshelf.

Upgrades and what to back up

An upgrade stops the container, pulls the image again and starts it with ~/.config/komga intact. Because the database survives, Komga is still claimed, the claim call is a no-op, and your admin account and password come through unchanged.

Two things follow from that. First, ~/.config/komga is the only thing worth backing up, and it is worth backing up, because it holds every metadata edit and every page of read progress you have ever set. Your books are safe either way; your library's organisation is not. Second, we track the current Komga image rather than pinning a version, so an upgrade moves you to whatever upstream has published. Upstream is active, MIT licensed, on 1.28.0 as of 29 September 2026 with five open issues, so that is a low-drama place to be, but it does mean an upgrade is the moment to read the release notes rather than a no-op.

Uninstalling removes ~/.config/komga. Your books are in ~/media and are not touched, because Komga could not touch them if it wanted to.

What it runs on

Any Appbox tier runs Komga. Comics and ebooks are small next to video, so storage is rarely what decides this: Appbox Lite is 500 GB at EUR 5 a month, Appbox +1 is 1000 GB at EUR 11, Appbox +3 is 3000 GB at EUR 14, all unmetered on a 10 Gbit line. If Komga is sharing a box with a Plex library, size for the video and the books will disappear into the margin.

You get a pro-rata refund in the first 7 days if it is not what you wanted, which for a library app is about the right amount of time to find out whether the scan and the sync behave.

The short version

• Your library is mounted read-only. Import Books and duplicate deletion will not work, and nothing else is affected.
• The paths in Komga are /data, /downloads and /flexdisk, not your home folder. Pick narrow library roots, because roots cannot overlap.
• Log in with [email protected], not your appbox username, and change the generated password: Komga's login is the only gate on its subdomain.
• The heap is capped at 1 GB, so the first scan of a big collection takes a while. Let it finish, then pick a sane scan interval.
• Back up ~/.config/komga. It holds your metadata and read progress, and nothing else does.
• Pair it with Calibre Web Automated if you want ingest, and with Kapowarr, Mylar, Shelfmark or Bindery if you want the books to arrive on their own.