There’s a crowdfunding thing for an iOS port on currently at $ 385.00.
I see someone called denim2x posted a goal of $ 800 – is this an active contributor? (OTOH I suppose they don’t have to be if it’s possible to run syncthing itself on iPhone and just do a wrapper that does iPhone-specific stuff.)
Iphone is a sandbox system which will never allow any app to put data available to memory other apps can read like its on Android. I doubt it would work to port a wrapper to IOS easily for that info a work colleguage gave me.
Getting syncthing running on iOS similarly to how it’s done on android is “easy”, I’ve had it up and running a few times as a proof of concept. But as Catfriend1 says the problem is that almost nothing is accessible from that point onwards so it’s not very useful. Files can be synced and accessed using the Files app on the phone. But photos are off limits[1], as are contacts, media, files in other apps like lastpass, and so on.
1) We can ask for permission to access them, but need to use a special API to get at them. It’s similar to the SD card issue on Android.But you could use it to easily transfer photos from your computer to your phone? (I know someone using Signal’s “Note to self” for that currently on iPhone, since the fsync app is not really usable.)
We could transfer them to inside the Syncthing container so you could copy them from the Files app. But we can’t get them into the Photos app without the above mentioned API.
Photos (and many other things) are not files on iOS. They are essentially database entries that may live in the cloud. You can ask to get the data for a photo, a bunch of stuff will happen in the background, and at some point you get a callback with the data. Syncthing doesn’t deal with that out of the box.
Btw, On Syncthing iOS port (again) 's napkin-calculation can probably be multiplied up a bit since data.syncthing.net says there are now about double as many Syncthing users =P
But that doesn’t require deep knowledge of Syncthing stuff, rather knowledge of iOS, or?
The correct solution is to write an iOS app that speaks the syncthing protocol, a la fsync.
rsilio does have an app, how about syncthing does get one too??? and i would back it also
could some developer open a kickstarter -like thing?! somone who really could solve this app demand? and we hop on to it and pay him
Nasty. Once files aren’t files any longer, but are these cloud-backed, dynamically assembled, temporarily existing, RESTless blobs, that’s something which I think is doomed to be impossible to sync reliably, longer term. It’s like trying to sync fog around. You would be assuming Apple never changes the API on you, and of course they would change it, as soon as they noticed you were encroaching on their exclusive back-channel access to those photos, etc. (because you potentially provide an escape route out of their walled garden).
Maybe I’m being too paranoid here? 
Probably. Yet the technical issue remains; it’s not just a question of compiling Syncthing for iOS. (Android is going there too, I suspect.)
and how does RESILIO solve it ?
By using the relevant APIs I’m sure. I haven’t claimed there is any technical difficulty there so I’m not sure what you’re implying.
i only try to understand, what is needed ( and may be what would it cost, can the api’s be licenced? ) to bring syncthing a similar app solution
Sorry for chiming in late. I’ve just found syncthing in a list of sync servers: I’ve been a fairly long-time user of nextcloud (and owncloud before that). You know the saying about filling vacuums.
Nextcloud has an iOS client that seems to work, and it’s open source. Perhaps the necessary tricks could be learned from it?
Secondly: whether or not iOS chooses to represent photos or anything else as files or blobs or whatever is clearly parallel-universe reality-distortion at work: photos come out of the camera as files, so there is a definite sense in which keeping them as files must be OK. iOS must have to do the translation itself when reading from SD cards.
Good luck with the mission!
I’ll try once more to be more clear.
We don’t need to learn the tricks; we understand perfectly well (at a high level) what is required.
Implementing it is a lot of work and none of us currently involved in Syncthing maintenance have the desire to do that work.
Explaining again how photos are accessible on iOS, or how other apps can sync things on iOS, doesn’t change this situation at all.
Someone who wants to do it and had the necessary time and ability just needs to do it.
may be money gives someone the necessaty and time 
Just not to bountysource please. Huge chance neither you posting a bounty nor anyone that invests the time will ever see that money again. Google about tos change if you want to know more (they reverted it for now, but the intent behind it was still terrible).
something like that you mean? https://www.reddit.com/r/pcmasterrace/comments/dut66o/potentially_huge_google_tos_change_youtube_may/
No, no clue what’s that about. What I was talking about is bountysource changing the terms to keep bounties older than 2 years for themselves. Bad move in general, criminal move because they wanted to apply that retroactively. After the backlash they reverted the change, but that doesn’t change the fact that any trust they had is lost now.