Hi,
Playing with Delta Chat I realize that files sent using the app will have the same limitations as attachments for emails, which mean probably around 25 MB or even less if some of the participants has lower quotas.
Maybe an integration with services like Firefox Send, which also locally encrypts files could be useful when you try to send a file bigger than 25 MB.
See Firefox Send client API implementation for reference.
Relying only on one company for that would be against the decentralization philosophy/nature of delta-chat.
(as far as I know is “Firefox send” fully in the hands of Mozilla)
We actually have plans for integrations with the dat-project which is decentralized.
Own-cloud integration of own instances could also be a solution.
until then we need to create the link manually and then share it with delta-chat.
A workaround for email restrictions could be: splitting large files to smaller peaces (unix split) and send them with several mails.
This would provide in general possibility to send unliminted file size 
But there is still the problem of inbox size.
It is great for unstable connections but with a limited quota we also would need an external server or a way in which both clients delete those parts once they have been uploaded or downloaded.
@Simon dat-integration is a bit for the longer term, as things stand. I think it’s interesting to find pragmatic ways to arrange for large-file transferal.
@nukeador do you happen to know a bit more about how Firefox Send works, if it is specified somewhere as an HTTP service and if there are other deployed providers than the central Firefox Send one?
Server code is open sourced here
You can set-up your own instance but there is currently no federation system AFAIK.
@nukeador k, i also found a docker-build repository GitHub - andreipoe/docker-firefox-send: A Docker image for Mozilla's Firefox Send designed to be built locally … so if there would be support in Delta Chat to upload to firefox-send instances, one could configure different instances for mediating the upload. The link would be sent via delta chat’s normal messaging in a special message. Also interesting is that there is a rust-command line tool GitHub - timvisee/ffsend: Easily and securely share files from the command line. A fully featured Firefox Send client. which does the client-side part. This might fit well into the evolving deltachat-core-rust work … all in all this looks like it’s a viable path for adding large-file support but it’s certainly quite some work, also on the UI side.
If someone could try out the docker repository and use it for uploads and downloads, that’d be nice to know that it actually works 
@hpk, I think this would be better for people on Cuba or other countries with an only-email connection.
Is email space quota free??
Better ask @adbenitez about that.
Also remember in box size… even when you’re deleting the file on the emailserver as soon as you downloaded it - what happens when you are off-line while people send you stuff?
Right: the inbox gets full and you can’t recieve any messages anymore.
I think keeping that in mind, it makes sense to do the “handshake”/matchmaking over email and let the file transfer be done in a different protocol/by different means.
Verification system: No new part is send until the old part is confirmed to be received (and deleted), this would work with read receipts system already implemented but making it mandatory.
Ah… that sounds too complicated, and if both are online anyway you can establish a direct p2p connection and transfer the file that way.
“Keep it simple and stupid”
Privacy, if not I would say “torrent”. And yeah is too complicated but not for me because I am not a programmer jajajajajajaja.
Then establish a p2p connection through tor 
For a joke is great, but there are several reasons because torrent over tor is not a good idea. The main reason is overflow the network.
https://blog.torproject.org/bittorrent-over-tor-isnt-good-idea this for others
p2p !== torrent
I mean the p2p where you download directly from your chat partner.
I know, and I repeat again:
Torrent has a verification system even to look for errors in parts and you can broke a connection and continue several days later.
I think dat would have similarities to torrent…
But anyways my Point was about why I think file sharing over email isn’t a very good idea.
Like e-mail is made for Letters but we need “E-Shipping” for big data-packages…
Does something like that exist? Something similar to email but for larger files?
I dont know, I was only proposing the idea to reduce a possible (in a future) dependency in external services (also exists lufi, used on https://upload.disroot.org as a replacement to Send). It is possible over e-mail why not try it?. Anyways, I began proposing this because @adbenitez told me there are (also) contracts only for email connection and not general internet in his country.
Oh, I just remembered some bad experiences over people who live in very far countries or locations (venezuela, chile and the main land of spain) when I was trying to send a file over torrent 100 kb/s of upload from my router and ~200kb/s of download of a friend and a final transfer rate of 4 kb/s (venezuela case) and with calls using SIP in p2p mode (to all that locations and using Linphone [no problem to near people and using the server except a year ago using the flexisip server from the Linphone]) with the lowest bitrate and quality audio codec and trying to maintain unstable calls.
I also tested tox, if I remember, with similar problems.
I thought on problems with high latency.