In my circle and family, threema is easily the most popular option of those listed here. the app was reduced quite a few times and could be bought for about 2 EUR. they also were one of the first “all privacy” messenges, so that might be why they are a bit more popular.
however, the situation with that paid gateway is very suboptimal 
and mstormi actually got me interested in the telegram binding.
Would be interested in Signal integration.
Hello,
I also use Telegram at the moment, but would also like to switch due to the lack of E2E encryption. Because of the running costs at Threema, I would prefer Signal.
Basically, I see two other messengers as options. That would be Wire and Messages from Google based on RCS. As far as I have read, E2E encryption is in the beta phase for Messages. However, I don’t know whether an API is planned or already available.
Awsome idea. I would love a Signal binding. I do not have Alexa or any cloud connection, so privacy is a point for me.
As far as I know, Signal has some Java code which can be used for a binding. There are some threads in the forum about an external script / application to build a Signal bot. A first class integration as a binding would be a major improvement and seems to find some users here.
To make the list of messengers complete: Matrix is probably a good solution for the future. Today, it is not widely spread but that could change. In addition, Matrix is the only federated server architecture. But a secure and privacy focused messenger does not help if it cannot deliver a message to anybody else.
I hope all this encourages you to do it.
Hope I can test the binding some day.
Hi Markus,
this is a topic which I’ll always thought I do it somehow in the future…
What I am just wondering: There is no way to send push notification directly from the openhab server to the Mobile app? I see the field “Benachrichtigungen” in the Android app but its greyd out with the message “Benachrichtigungen nicht verfügbar: Server für den Fernzugriff ist keine openHAB-Cloud-Instanz”. So still there is a OpenHAB cloud instance necessary for direct push notification? This would be the first thing I’d like to use as I use the openhab app quite intensive. This way there is no need to go via Threema and friends. This might be the 2nd step.
Cheers
Marco
At this point, I’d be careful with new google products. Lately they have been abandoning them even faster than before …
Another Idee: Integrate Message on Openhab-App and not use a messanger?
It is with noting that you really don’t need to use your real phone number with either signal or telegram. There are a number of sites that you can use to get a fake phone number that can receive the SMS messages required to activate the account. TBH, I have not researched how much info you need to provide to get one of these, nor how long you need to hang onto the number. I think with signal you are good to go after initial login, but telegram you might need to hang on to it for future logins.
–Scott
What about the Matrix protocol?
It’s encrypted, federated so you can host your own instance and still talk to everyone, hast SDK and bot examples available and it just works.
The Element client is really nice as well.
We switched a couple of years ago and never looked back! 
Hi Manuel,
that’s what I mean, the infrastructure for push notification is there I think…
That would be the first mechanism I’d consider.
Right now it looks you need a openhab cloud instance to get push notifications.
Don’t know how it compares to the others in the first post but there is also a binding for pushover which is a small one time cost for the app and then unlimited use. I have used Telegram and Pushover and they both are good and have different things about them that I like.
Please consider matrix.org as was suggested by @Spaceman_Spiff !!!
I have the same security/privacy concerns as many of you and the Matrix/Element combo is very good. It can be as self-hosted as you want, or cloud-based for those who don’t care as much. Fully open source, and the protocol itself is technically beautiful (handles every corner case I’ve seen with grace).
Hello together,
if you want to have all possibilities and you have the space and knowledge for it, go ahead with Mattermost. It’s a simple Signal, WhatsApp, Slack Alternative. Inclusive a Desktop- and a mobile App - for Free.
It’s OpenSource and you can host it onsite on your own servers. They have an open API which can be connected to send automatically messages. We use it in our company since 2 years. Working great.
I am thinking about integrating this API into to my local openhab Installation so I can be notified without any costs, securely over our internal servers. And my Childs / Wife have only one additional app at there mobile phones.
What do you think about this alternative?
Michael
Hi,
I read on the Mattermost website that there is only one transport encryption, no E2E-encryption, did I understand that correctly?
Best regards Ulf
Hello Ulf,
that’s correct. But when you install it at your own server, you have the full control.
Michael
I think maybe we don’t need to get caught up in a format war here. Someone is offering to write a binding and I think that’s great… and we can try to influence but I doubt anyone would convince me to switch from Matrix/Element to Mattermost nor do I believe I could convince Ulf to do the opposite. Ideally OH would be the “one ring to bind them” and have bindings available for many/all of the popular messaging systems.
In case @markus7017 decide to not choose Signal, I could myself decide to build a Signal binding. I did not know there was an API available.
More choice we have, better it is for the users. I don’t think we have to choose only one solution.
Regarding Signal, I do not find an official API. I see signal-cli project but it requires platform specific libraries to run. I am not sure it would be so easy to develop a binding that would work on any machine.
If Signal has no public API, then I’m not interested in using it.
I believe there are other more reliable applications out there. For example, Utopia p2p Home - Utopia P2P Ecosystem all-in-one application that allows you not only to successfully communicate, but also guarantees anonymity, but also complete security of personal data. Plus, it’s completely free.