The Android App

I’m probably just being a “me too” but my $.02

I also use ST Android (but not heavily just for syncing pics and stuff also one Keepass file). It works fine for me. No noticeable crashes or battery drain issues. In fact I don’t know if I can recall the last time it crashed on me. I use a Samsung Note 4 and Note 2. Both stock and unrooted. I wonder if rooting, custom roms or bootloaders (TWRP, ClockworkMod) could be causing these instability issues.

Back in my day I did all the “ things” too and used custom roms and BL’s you name it. Also had lots of instability and battery issues because of it. I have since those days grown tired of modding my phone and constantly having to odin it back to health every weekend. I have noticed also, since then, far more stability from my apps and phone in general. I wonder if that’s also an issue for some.

Admittedly I only use ST much to Sync my windows home and work boxes (it rocks on Windows). Most of my Linux’s are servers (and VM’s at that) and don’t need to sync anything with my workstations.

Thanks Felix for your hard work on the Android side.

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Try synching 50gb (which is roughly what I have here, mostly Music). I also have Note 4 stock rom (but rooted) and it crashes and eats up my full battery like there is no tomorrow in 2 hours.

I don’t think I will try. Though I imagine it would be rough.

I use to copy music over to my phone, but I like my new phone-music solution. I have petabytes and petabytes of music stored and playable on demand. I use a couple of apps to access them whenever I want. I’ve even given those apps a name, I call them… youtube red, soundcloud, pandora, etc. :wink:

Well the reason I prefer local is that memory is cheap and mobile data is expensive.

Not all my mobile devices sync 50gb for sure. Some are down to couple gb and syncthing still causes issues.

My few cents here:

I do use the android app on daily basis, and it does it’s core job (syncing stuff). The utility of it is absolutely great.

However I do agree that it is a PITA to manage: The wrapper’s UI is very unresponsive and super slow, often hangs (while ST itself is alive - files still fly around). I often would give up just trying to get to the debug logs without the UI hanging on me. so I came to avoid using the “native UI” as much as possible.

What I normally do (with my device and other that I help people to set up) is as follows:

  • Install, while it’s still “light” - configure android app’s settings (run conditions, etc.), set Web UI password.
  • Back up settings.
  • Exclude it from battery optimizations.
  • Now everything else I do via network. Access the Web UI via browser from some PC on the same LAN, and configure all the rest, folders devices, etc. Using the Web UI remotely like that is much easier, responsive and besides, there are many settings that are missing from the wrapper’s GUI (some versioning options and more).
  • Now after “set it” i’d “forget it” and usually it works OK.

btw: I know i should be able to access WebUI within the app as well, but again, the wrapper itself will often hang before i get anywhere. And also - in 99% of cases I can’t access the web UI from within the app once I set a password for it (remote access is fine though…)


Okay the semester landed on my shoulders. Alas I won’t have time to test out different sync techniques and chase down crash logs. Back to dropsync for another few months!

Sounds like the method outlined by scienmind would solve most of the problems I experienced, but that is a lot of effort to deploy to “normal” users in my group.

Just an information about a general problem of current Android. There is a problem which causes devices disconnecting from 5 GHz wifi. My own experience:

old 2,4 GHz router: Syncthing app is super stable and never crashes, has to be restarted or does any other worries.

new 5 GHz Linksys WRT3200ACM router and my previous Asus N66U: constant disconnects, devices goes offline, if I start the app, the background service cannot be found and the app has to be swiped to end it from the recent apps list.

Maybe this info helps to find any kind of connection keep-alive for 5 GHz wifis.

I confess I use Resilio Sync to wirelessly transfer music from my desktop to my phone, using my phone. Syncthing not being able to do selective synchronization makes this impractical given how much I have stored on my desktop.

I was hoping Anywhere Sync Browser would allow me to do this without having to run Resilio Sync on my desktop, but for whatever reason, it doesn’t work for me. Whether this is because it struggles with an index for 800GB of files or something else, I can’t say…

It’s actually possible to set syncthing to use an external sd card. All you have to do is go to configs>behavior and check the ‘Use advanced folder picker’ box. Then, when selecting the folder for syncing, just pick /storage/extsdcard.

What exactly are the problems with the wrapper? Are there issues for this on Github?

@Rudeus Unfortunately, Android will not give the app write access to those folders (unless you use root).

@Nutomic Oh,I forgot the android version on my phone is the 4.3.

I use Syncthing on two Android devices, a phone and a tablet. On the phone (a Moto G4), it works flawlessly, but that’s because I’m only using internal storage. I sync the phone’s pictures and a few folders that have notes (recently replaced Evernote with Orgzly to do this).

On the tablet (LG GPad 8.3), I have 16GB of internal memory and a 64GB micro SD. This is where I have the most problems, and I don’t think it’s the fault of Syncthing; rather, I think it’s a limitation imposed by the design of Android.

To get this to work at all, I must have the tablet rooted and have used the SD Fix app to restore pre-Kit-Kat functionality to the SD card. Otherwise, Android itself limits access to the SD card. My tablet is running Lollipop, and this seems to work (see below), but I understand further changes were made to the way SD cards work in Marshmallow and Nougat, so this could still be problematic in newer versions of Android.

Even with these changes, I experience the UI lockups noted by others above. The binary keeps running and syncing, but the UI becomes unresponsive and Android asks me if I want to kill the app. This means I wind up only starting Syncthing when I know something needs to be synced, and then I reboot the tablet once I see that it has synced.

The only difference between the two devices is the use of the SD card. I don’t think this is the fault of the Syncthing android app. I think Google is going in a particular direction: if you want lots of storage, buy a more expensive device that includes it internally. For me, this is the wrong direction: I want to stick a big SD card in there and sync lots of stuff to it, because I basically want an ultra-portable computer, not a streaming-media consumption device. That’s why I have the keyboard case and everything.

For this reason, I’m strongly considering an Ubuntu tablet next. I think whatever the Syncthing Android developers do, they will be fighting an uphill battle with the platform itself. @Nutomic and crew have done a fantastic job in their spare time getting Syncthing to work on this platform, and they should be applauded for their efforts. But ultimately, I think Google, despite the low cost of local storage, is doing what they can to push everybody into the cloud, and that’s a strategy that I, and I suspect many people who use Syncthing, don’t agree with.


Marshmallow introduced adoptable storage where you can format your SD Card as “internal storage” and use it like that. Then Syncthing can write to it without problems.

I know about the pains a lot of people here report and a few months ago when I had a little free-time on my hand I tried to track down some of the issues, even brought some minor fixes that got it working on my device. And that’s exactly where the main problem starts: the incredible amount of different devices with different Android versions and various vendor-specific modifications. It’s almost impossible to track down some of the reported issues without owning the affected device.

I for my part have a very well working syncing solution with this app, based on the various background options and stuff. For me it simply works and I never open it. So I’d like to express my gratitude to @Nutomic for offering this solution and for investing so much unpaid work into it!

I know, that unfortunately this is not going to help anyone who has affected devices. But I just want to add some praise, before @Nutomic gets the impression, that everybody is just ranting and nobody is enjoying what he created.


Yes, and then (AFAIK, I only read about this; I haven’t tried it) you can’t take the SD card out and read it on another device. And you can’t remove one SD card that has, say, work data on it and stick a new one in that has movies or music on it. The point is that the natural way of using SD cards as portable, cross-device, extra storage has been disabled by Google. Whether it’s for “security” or to push people into the cloud, it’s not right.

I advise not to use it as internal. You will end up having issues when upgrading rom.


I think that the issue is that Go binary behaves differently on different devices it is not necesarily the sd card issue. The reason I am saying is that I have many android devices with many versions. The quality of Syncthing on these devices greatly.

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I never had any issues with system upgrades. The only problems I had were lock ups and forced reboots until i switched from a 10-20MB/s card, to a ~70MB/s card.

Can confirm this is an issue between major android versions. Also, rendering an sd card completely non-portable is a bit of a pain.

On the spot! Just as I described before - find a way to set it up, and forget about it :slight_smile: (unfortunately it’s not a “average user friendly” solution overall)

I believe everyone here greatly appreciate @Nutomic’s work. I was hunting for a secure, privacy-friendly FLOSS multi-platform file transfer solution for ages, until I finally came by syncthing one day.

This thread should not be seen as an angry rant collection, but rather a non-github, alternative feedback.

After all, we all are here to help syncthing improve and spread, and “return the data to the people” as a result. Helping people over the world to escape “want convenience? then give us your data” software philosophy.


As the thread starter, I definetely appreciate the hard work done by the devs, that is for sure. No one has obligation to spend their precious life hours to work on tools like this. It is just that sometimes we have to come down with hard critique to improve our tools :wink: