Möbius Sync iOS client now in beta

Following the helpful feedback and discussion in my previous post, our iOS client is now called Möbius Sync with beta build available to download via Apple TestFlight here. See https://www.mobiussync.com for more details.

I’m creating a new topic to avoid the old unpopular name from continually resurfacing, and happy to keep discussing the issues here.

The intention is to release at a low up-front price, with no ads and no analytics (except for Apple’s mandatory app store analyics).

Hopefully these changes are seen as improvements and the new iOS app helps expand Syncthing’s reach for everyone’s benefit.

I will respond to the specific suggestion of open-sourcing the whole app later.



Thanks for addressing the name concerns, very happy someone is working on filling the ios gap. Wish you best of luck!


I should be clear: there are now no ads and no analytics (except for Apple’s mandatory app store analytics).


Moving this discussion in here:

I really do wish there could be an reasonable way to open the full source code. I’m not worried about a small number of users taking the source code and compiling it for themselves; I am worried about another dev resubmitting to the App store and undercutting me.

I’ll keep researching and exploring this for the medium term, and keen to hear more from anybody about this challenge, but for now, I’m pretty set on getting it out there and we’ll see what happens down the track.

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This is not exactly related to the application, but your website seems to load quite slowly. I am not sure whether this is mainly due to my distance from the server location, but the site seems to be way heavier than it should be (judging by the minimal visible content).

Please check https://developers.google.com/speed/pagespeed/insights/?url=https%3A%2F%2Fmobiussync.com.

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Ironically it’s currently hosted on Google Sites. (We’ll be moving it elsewhere when we get the time.)

Awesome! I love this new name, and it feels very appropriate and differentiates your brand nicely. :slight_smile:


Yes, just off the top of my head, within my circle of friends I can think of 11 new users right off the bat. I’d imagine this could be one of those apps that doubles the Syncthing userbase.

Can’t blame you there, it’s definitely the easiest for drafting up something in under 10 minutes without a VPS or object store. I use GSites for projects all the time, they’re pretty awesome despite the bloat.

Oh. Yeah, okay, that’s fair I suppose. Is there any chance that the wrapper could be made “source-available” as a reproducible build to trusted members of this community and protected by NDA/noncompete just to audit the code and vouch for the safety either publicly within this forum, and/or as a shoutout on your site?

…am I being too paranoid here?

I’m just really, really concerned about the security of my data. Medical records, tax records, business documents, bank statements, family photos, journals…

Well, then again, I guess most users of Syncthing are this security-conscious.

EDIT: replaced ‘privacy’ with ‘security’.

This is indeed the thing with open source; anyone can publish it on the App Store and charge for it. :roll_eyes:


Disappointing about closed source. I don’t have a problem with charging for the application, the lack of an iOS client was a big dealbreaker with Syncthing but if I’m forced to use closed source applications I might as well use Resilio.

I also can’t think of any examples where a dev took open source code and resubmitted an app to undercut someone else. So I fail to see the justification for the paranoia.

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I have seen seen cases like that in Android, although it was a little bit different. The original application was free and open source, but some people would fork it and then release on the Play Store under a different name charging money for it.

Sure but thats on Android with Google’s extremely lax rules when it comes to publishing apps to their store. Last time I checked Apple doesn’t even allow anyone to publish GPL forked apps on their App Store.

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Long time Resilo Sync user, currently looking at alternatives since they removed support for Windows Server for all except their really expensive business plans.

Would have moved over to Syncthing before, the only thing missing for me was iOS support. So really excited to see Mobius Sync! Thanks!

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Xmas came early this year! I’m so glad to have this. I bought my first ever iPhone recently, and was so disappointed to find out that there was no syncthing for it (and honestly, I’m also disappointed at very many things about the ways these iPhones work generally).

I have tested your app, and it is working great for me. In your other thread, you mentioned that it will try to occasionally sync in the background. How often does it try?

I look forward to paying you a reasonable amount for this app.

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I’ll be glad to test this!

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Happy to see this (and testing it). For me, the lack of iOS client is a huge dealbreaker as well, so I’m super happy to see this happening and will surely buy the app. I am not as strict on closed source as others here, on iOS that’s unfortunately the case anyway. I wouldn’t mind a free ad supported version although I wouldn’t use it. Also I’d pay for a non-subscription app (assuming reasonable price).

One technical suggestion that would be fairly important for me is a selective cache of some sort, similarly as for nextcloud: As of now, Moebius Sync will sync a complete Folder which can be 10s of GBs which I don’t want permanently on my phone. But I may want to look for stuff on the go and download files here and there (assuming I have syncthing instances running somewhere).

The only choice I have now is to create a separate “Mobile” folder with only the necessities but risking that I can’t access data on the go that is somewhere else.

I am aware that this might be hard to implement (though definitely not impossible) and it goes a bit against the concept of syncthing (it’s not client/server) but I’m just putting this out because it would be extremely valuable for a mobile client.

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Just wanted to add another PS: I understand your concerns about somebody else selling your app if you make it open source. But I need to agree with other people here: I think it will be unlikely a threat for two reasons:

  1. KeePassium and StrongBox are both commercially successful apps but source code is public. Both work very well and I do not know of a case where this was an issue. You could consider contacting their authors on their view/experience on this! And JFYI: https://keepassium.com/articles/keepass-apps-for-ios/

  2. Your potential customers are not 99.9% of iOS users who neither care about or have no clue about security/privacy … it’s the 0.1% that does. These potential customers value transparency and the ability to audit the code. By not making the code public, you are risking to loose exactly those people who regard such a syncapp as security critical.

  3. Your potential customers (or most of them) are the ones who understand the ecosystem. Those people won’t be tempted to use a stolen app. An app that’s obviously stolen will likely not have a chance to succeed.



Does this NEED to be ios14.1?

Tools like this are really great for retiring devices.

But also I’m on 14.0 (for some development reasons) and it’s not supported.

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Would love to download this, but I’m getting “This app is not available in your country or region.” I’m in the US.

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Thanks for the positive feedback. There is no application control over how often the background syncs run in iOS, so once the initial release is out, I want to focus on the various ways to work around this.

Indeed that’s on my personal wishlist too, but I imagine it’ll be quite difficult to do too.

The big question for me is whether to embark on that or photo upload first.