Signal Secure Backups

Backing up Signal on Android for free and offline was ~always possible. The app creates a multi GB backup file on the phone memory under the Signal folder that you can just copy out and back on a new phone.

The file is encrypted with the passcode and the database can be extracted.

https://github.com/bepaald/signalbackup-tools

There are a couple of problems with the existing backup:

1. It is non-incremental. This means you'll need about as much free space on your phone as your Signal database takes, and it may take many hours to make if your database is large (mine is 18GB). I used to wake up to find my phone had not even fully charged because it had been so busy writing Signal backups.

2. Once you have it on disk, how do you get it away from your phone? Especially after SyncThing disappeared from Play Store (because it was basically a non-Android app behind a thin Android shell that couldn't easily be upgraded to more modern native APIs), there's nothing super-obvious here.

I would have loved a better solution for local backups, but realistically, $2/month for cloud backup is really cheap, and a pragmatic solution.

> Once you have it on disk, how do you get it away from your phone?

adb pull no worky? At least for HN readers.

Any backup that needs manual intervention is no backup.

Thought people are talking about backups without a "cloud" involved. So you'd need to manually connect your phone to something...

Wireguard + syncthing (from F-Droid) work fine. Triggering it when the phone is on the charger makes it very easy to sync things from a computer to the phone, while next to the computer.

To be clear, Signal + Syncthing also works fine, that's what I have.

It absolutely does not work fine. Keeping 2x the size of my database in free space on my phone to let backups work it's no solution at all, which is why I stopped doing it. (The backup creates two files - current and previous, and Syncthing can't remove complete files to another location, so you need an actually rather difficult to write script to do it).

I never really grokked Syncthing.

I recently vibe-coded a crappy Windows Go GUI to grab files off my phone via rclone & sshd4a and then optionally delete them, but it's a very manual process since sshd4a has to be running on the phone before I initiate the pull.

Syncthing is just open source Dropbox, self hosted.

It's entire purpose is "make two folders identical".

It's very good at that: so good that I frequently wish it did other things - i.e. if it had some notion of minimum seeding levels so it would destage files off a device provided they were replicated elsewhere (e.g. automatically clearing old photos off your phone would be a good use of it).