Compatible XMPP Clients


Continuing this discussion:

Unfortunately most of my friends and Family have iPhones and can’t install Kontalk.

So I was searching for a spreadsheet telling me which XMPP clients are compatible, but didn’t find any. I only found this on Wikipedia, but Kontalk is not even on there:

So, next I checked PrismBreak and they only recommend ChatSecure for iOS, so I’ll test that now.

Now to my question:
Should we start a spreadsheet of compatible clients with one column for basic support and some more for additional features like encryption and group chat?


As a matter of fact, Kontalk is 100% XMPP compatible + a few additions such encryption and a few other things. But for the rest, you can use a normal XMPP client to connect to it.
The problem is that Kontalk uses client certificate authentication. It’s not a custom thing, it’s very much standard, yet there is lack of support from clients. That I know of, only one desktop client supports it: Gajim. I don’t know about iOS clients, but I can’t find one.

I recently wrote a Pidgin plugin that also handles the client certificate authentication part (and also encryption and key retrieval), so you might say Pidgin is compatible.

Even bigger than authentication, another problem is registration. Given an existing account, and if ChatSecure indeed supports client certificate authentication, you just have to throw it the kontalk-login.p12 file from the personal key pack exported from the Android app after having registered.
On a different note, I’m actually thinking of building a web-based registration module that just generates a personal key to be imported in any client…


I have tried from gajim to send an encrypted gpg message and I have not got it. Can you explain how it is done? thank you very much


PGP encryption in Kontalk is not strictly following XEP-0027. We had to modify it a bit to patch some serious security issues with the spec. When I was talking about Gajim, I meant that Gajim supports the authentication method Kontalk uses.


I managed to add a friend who is using kontalk to my xmpp roster. But encryption is not working as Kontalk doesn’t support OMEMO and I don’t know where to find my contacts publig GPG key. Are these keys available outside of the kontalk network? As I prefer XMPP with my own server I don’t want to install kontalk for chatting with this contact.


I’m not absolutely sure.
But if I Export my personal key in the Settings of Kontalk App, there will exported “”. Inside this ZIP-file is a file named “kontalk-public.asc”.
I think this is the public key.

Maybe you can handle this. I’m not a tech :wink:


The public keys can be retrieved via XEP-0189, but you won’t be able to use them to encrypt because Kontalk uses a slightly modified version of XEP-0027 for security reasons. When we’ll support OMEMO we’ll be fully compatible also at the encryption level. Sorry for now you’ll have to disable encryption with your XMPP contact.


Thank you for the clarification. The unencrypted chat is no fun for my friend as he says he get’s a warning pop up with every single message so I wait for OMEMO support till I use the xmpp - kontalk combination for chatting.