Threema is going Open Source!

Hey People,

I just got news from the Threema-Channel… They are going Open Source!

Within the next months, the Threema apps will become fully open source, supporting reproducible builds. This is to say that anyone will be able to independently review Threema’s security and verify that the published source code corresponds to the downloaded app.

I’m no developer, but here are many… maybe there will be a way in the near future to build a native secure Threema messenger for the Sailfish-platform. That would be so awsome!


You have funny ideas :grin: Android fork maybe, but a port for SFOS?

The current native Sailfish client is very, very basic so this may help indeed.

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This guy apparently already ported Threema to SFOS somehow :slight_smile:

Will it be compatible with Threema Work?
so can I contact people there too or is this some kind of internal Server thing for the company

Dieser Tweet stammt von einem Account, der nicht mehr existiert???

@4carlos bei mir gehts. Such doch einfach mal Kool-Aid Man auf Twitter, der hat vor längerem, wie auch immer Threema auf SFOS portiert :wink:

At least he claims that he ported it, I do not find it in openrepos and also in the web no other mentioning.
Does anybody know something about that client?

It was available on OpenRepos for a while, so a few people should still have it.
But it never was a full-functioning client.
It’s fine for sending/receiving Threema text messages but there are still issues with sending group messages etc.

Apparently Kool_Aid_Man has deleted his repository in openrepos, given that he used the same alias there.

The repository had to be deleted for legal reasons.
Or, to be precise, because of the lack of time the developer had to work around said legal reasons.
( no, Threema did not threaten to sue :innocent: )

That’s a pity.
I am totally clueless what kind of legal problems these could be.

Should Threema really open-source their code so we won’t have to rely on reverse-engineered stuff any more this may open completely new possibilities. But let’s wait for them to actually deliver.


Question is: do they just open the client code or also the server?

they were talking about the clients in their announcement

That’s a pity. So it will stay centralized, not different to Telegram then.

This is not a port in the strict sense of the word. Porting the client will not be possible due to the different UI and different API calls.

Kool-Aid Man will have used the Message API which is available to third parties. We won’t see a real 1: 1 ported Threema client on SFOS. However, a modified client for Android is possible without much effort. For Sailfish you almost have to reprogram from scratch. The source code can only give hints how to do it.

Open source here rather means that the source code is open and can be compiled for Android yourself with certain requirements.

That’s what I think


The server is the heart of Threema’s infrastructure and a secret. If you really want to be free, use jabber / xmpp.

The app uses an open-source re-implementation of the Threema protocol:


Ah, OK. I only suspected it because I couldn’t imagine that this app was based on the original code.

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