BasicSync and Synctrain: solid apps for bringing Syncthing to phones
One of the best ways to defect from big tech’s cloud storage services — Google Drive, OneDrive, iCloud — is a piece of software called Syncthing. It lets you sync directories/folders between multiple devices directly, without storing files in the dreaded cloud.
If your devices are all computers, zero problem: Syncthing has official binaries for the three major operating systems (Linux, macOS, and Windows), plus a few niche ones — FreeBSD, OpenBSD, and illumos, the last one new to me. On macOS and Windows, there are even packages that bundle startup configuration alongside the system and tray icons. Good stuff.
On phones and tablets, the picture is more complicated. The Syncthing project maintained an official Android app until late 2024, when the lead developer announced its discontinuation due to a combination of lack of app maintenance and “Google making [app] publishing something between hard and impossible.”
A fork called Syncthing-Fork announced it would keep going, only to get tangled up a few months later in a rather odd mess involving two apps with the same name from two different developers. They sorted it out and the project keeps receiving updates, despite the dent to its reputation.
On iOS, things were even worse. There was only one app, paid and proprietary, called [Möbius Sync](https://apps.apple.com/br/app/m%C3%B6bius-sync/id1539203216
Möbius Sync). It works (I actually bought it), but it doesn’t inspire much confidence either, and revisiting it now, I notice it hasn’t been updated in a year and is still parked on Syncthing’s old engine — the project had a major update (2.0) in the meantime.
Fortunately, new (and good!) apps have emerged to fix the shortage on mobile devices.
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On Android, Andrew Gunnerson released BasicSync in November 2025. The app lives up to its name, as he points out in the project repository’s brief description:
The app is intentionally kept very basic so that the project is easy to maintain and keep updated. BasicSync only controls when Syncthing runs. The actual configuration is done through Syncthing’s own web UI.
The part he describes with excessive modesty (“only controls when Syncthing runs”) is done with a lot of care. There are alerts for errors and file version conflicts, controls to switch the sync mode (manual or automatic), and, most importantly, the way it was built to make BasicSync immune to the background-process restrictions Google introduced starting with Android 12, which make it harder for this kind of app to work.
BasicSync isn’t on the Play Store. You can install it via F-Droid or by downloading the installer (*.apk) directly from the repository. (To make things even easier, add the address to Obtainium.) The extra effort is worth it.
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On iOS, there’s Sushitrain. On the App Store it goes by Synctrain, because Sushitrain wasn’t available. The name is a nod to sushi restaurants where customers order via tablets and get their food delivered on a little train that runs between the kitchen and the tables. It’s been on the App Store since January 2025, it’s free, and open source.
Right off the bat, Synctrain stands out for feeling right at home on iOS. That’s no accident, since the app is built with Apple’s own technologies — Swift with SwiftUI. The core, responsible for file syncing, is written in Go. (Not that this paragraph matters to you at all; just a bit of trivia.)
Synctrain has two important features that are often missing from Syncthing-based apps: on-demand downloads and selective sync. Both exist in iCloud, for example. (I imagine other cloud storage apps have them too.) They’re great for anyone low on phone storage or who’d rather not carry every single file from a computer directory around in their pocket. The app also allows automatic photo and video sync outside of iCloud.
Otherwise, it does its job as you’d expect. Which, on iOS, means it needs some attention. Like Möbius, Sushitrain/Synctrain also sometimes struggles to run in the background. You can set up notifications, and opening the app shows alerts including the time since the last sync with other devices.
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A little over a month ago, I turned off syncing for my documents and macOS desktop via iCloud Drive. I switched to Syncthing (macOS) and Synctrain (iOS) so I could sync only the document directories I actually need when I’m out and about. There’s no reason to carry around bank statements and tax documents, or my journals, all the time. iCloud Drive’s model is all-or-nothing. With Syncthing, I can pick which directories to sync and I’m not limited to just two preselected by Apple; any of them can join the party.
If you go down this same path, don’t forget about backups! Personally, I’m using rclone together with Backblaze B2, as I explained in this guide/tutorial [pt_BR] from January 2022. It’s a bit involved for regular folks. A routine of copying files to a USB drive, or the help of an app like Parachute (iOS), would already solve the problem.