Battery saving for syncthing-fork on Android with (1) global discovery or (2) tailscale?

protonaut · January 2, 2026, 11:50am

I’m asking myself which scenario of using syncthing-fork on Android is better for battery saving:

(1) To use “Global discovery” to make sure syncthing-fork connects to all the other clients.

(2) To connect all the clients through tailscale and disable “Local discovery”, “Global discovery”, “NAT Traversal” and “Relay” in syncthing-fork. This option requires to additionally run the app tailscale on Android all the time.

I’m not sure if there is a third option:

(3) I already tried to install a private relay. Although android-fork could connect to the relay I couldn’t find a way to discover/connect the clients through the relay. But even if I worked this out I don’t think this option is better than the first option in terms of battery saving.

Background: I already tried to reduce the power consumption by using the option “Sync every hour for 5 minutes” as is stated in this wiki:

github.com/researchxxl/syncthing-android

wiki/Info-on-battery-optimization-and-settings-affecting-battery-usage.md

main

First things first:
* Syncthing-Fork requires to be exempted from doze which is asked during the welcome wizard. The app will cease to function if the permission is revoked.
* The app doesn't require the permission to "waste" your battery. It does run a reliable so called "Android foreground service".
* Technically speaking, it's required to avoid database corruption in case Android can't communicate with the SyncthingNative before putting the app and SyncthingNative in suspend.

Here is how you can reduce battery usage even further by optimizing Syncthing's settings:
* If you've configured your Syncthing instances to connect using DynDNS or static IP addresses, turn off all discovery options: Go to "App/Settings/Syncthing Options" and disable "Local discovery", "Global discovery", "NAT Traversal" and "Relay".
* If you've configured your Syncthing instances to connect devices which are located on the same local network, turn off global discovery and relay options: Go to "App/Settings/Syncthing Options" and disable "Global discovery", "NAT Traversal" and "Relay".
* If you don't need your changes immediately synced between devices and can wait for up to an hour until the changes are synced, go to "App/Settings/Run conditions" and check "Sync every hour for 5 minutes". The app will then stay in the background showing its notification all time but will only do its work in "5-minute-time-windows" every hour. This will save a lot of battery but practically require an always-on device on the other side.

Short summary:
* Optimize for better battery life
  * Pros:
    * You'll totally love Syncthing's efficiency.
    * Good for advanced and expert users.
  * Cons:
    * You have to do more "caretaking" on how you setup communication between devices yourself.
    * You might come to the point where you like to use an always-on server as a partner for your phone.

* Optimize for faster sync

This file has been truncated. show original

protonaut · January 3, 2026, 11:50am

I found a solution. It requires a two step configuration:

(1) First you have to let syncthing do its job with full global discovery and so for connecting to all the clients. (It doesn’t work to connect the clients through a private relay in my experience.)

(2) After all the clients are connected it is possible to switch to a relay and while disabling all “Local discovery”, “Global discovery”, “NAT Traversal” on the client. So no tailscale on android is required.

In the end you get a battery saving but working syncthing-fork configuration without any discovering services needed on the client.

Consider: In case there is a need of connecting an additional client I asume it’s best to just repeat the steps (1) and (2) again.