Asklemmy

Signal ?

Signal, hello?

Signal.

Signal!

nothing better than Signal

Signal is probably the simplest to get started with.

There is also element/matrix for more of a discord type feel.

SimpleX if you want something more anonymous.

Everyone is saying Signal, but my family uses a Matrix space (mix of phones and PCs in this case) and it works great. It's FOSS, federated. Truly future-proof.

https://www.privacyguides.org/en/real-time-communication/

signal, simplex

I'd recommend Threema. It's privacy focused, based in Switzerland. You don't even need a phone number to create an account, they collect no data on you (claimed, but haven't checked) and the code is open source, under A-GPL 3 license.

There's a build for Apple and Android, for which you pay once.

I use this to talk with important family members.

Signal

Signal is a nice suggestion but is based in the US meaning they could be subpoenaed and legally not allowed to say. It's unlikely you'd be targeted though, unless you're a very high-profile person. If you're concerned about where servers are being run and who by then matrix is a great alternative.

I've been using Delta Chat for the last few weeks, its very similar to WhatsApp, but decentralised... Works very well, available on android & ios, definitely worth a look, as it could be good for your use case..

https://delta.chat/en/

I just got to know about Delta Chat which sounds fantastic as it basically uses your email but wrapped as chat.

XMPP and Matrix are other good options too, although these require creating an account (Delta Chat can work with your normal email account).

The good thing about these last 2 is that they have calls and all that stuff.

Clear vote for Matrix.

Easily works with basically every system from iOS, Android, Windows, Linux,Mac and there are Web-Clients as well. And everyone can find their own client of choice.

You can use one of the huge federated instances like matrix.org or set one up yourself.(Which is much easier than setting up an Activity pub instance,btw.)

There are rooms/channels that can be open or semi-open just like in Telegram, and bots are absolutely not problem (Not Like in signal). Registration is not bound to a phone number like it was in signal for a long time (but is no longer) and (unlike still needed in signal) a phone does not need to be used for sign up&transfer between devices works seamlessly.

If you selfhost or use beeper you can even bridge to different services (signal,WhatsApp, telegram) etc. so you only use one app for everything.

I'll be different and say Session.