Only because nobody answered with this one:

IRC

Decentralized and an open protocol. Client setup to connect is not so straightforward, but it's a one and done. Very robust.

I'm allergic to centralized communication schemes, though I do use signal to communicate with one person.

I want to research some of the other suggestions that have been brought up, so thank you for the post!

Matrix is only really enjoyable with unencrypted chats.

I have fairly recently switched phones. Now, a good number of older messenges fail to decrypt. Even when I don't switch devices, a group chat for a three day long event with a very small group already gave us lots of fun decryption errors. Oh, and I have this other fun group chat where Fluffy Chat constantly reminds me that people whose devices I haven't verified will be able to read my messenges every time I send something. Also, Matrix has coutless clients with different feature sets and I heard calls are a pain to ßet up.

Signal, on the other hand, just works. Federation and decentralization is obviously nice but a functional product is more importmant. I haven't had a chance to try XMPP unfortunately.

Simplex

• If you have a targeted group/peer need then whatever they are using or whatever you all decide right in the beginning - I'd suggest Matrix or some other decentralised alternative, definitely not Signal.
  • Matrix had the huge opportunity to be "the messaging app" but they neither became good at corporate usage and definitely ended up sucking at personal usage. They started doing too many things, at once, and while completely ignoring the individual user.
• If you want a wider general acceptance then sadly Matrix is DoA. WhatsApp becomes a huge choice outside USA and China but it has started becoming shittier by the day and looking at who has become WhatsApp's global head now, I don't think it's gonna get any better (check his last "app" or company's screenshots and come here if you don't end up vomiting). So Signal or maybe some other similar app. You are limited by societal trends and acceptance here, not the tech or finesse or privacy of an app.
• If you just want privacy and a simpler app, proven (at least so far), then well Signal it is, as much as I hate it for reasons they decided to make it a centralised messaging app and then stuffed crypto in it etc.

I prefer matrix for two main reasons:

• I can host my own server (and I do)
• It's not centralized

As a bonus it has briddes for almost anything you can think of, so I use the signal bridge.

I created this to help find active matrix rooms https://activematrixrooms.com/

I use both signal and matrix.

I actually prefer XMPP. It's also less of a hassle to set up than Matrix and the protocol is much more mature. There are still issues, but it's rather functional for audio and video calls (if you're using a supported client).

Edit: For clients, I use Cheogram on Android and Profanity (which is a TUI) or DinoX (for calls) on Linux.

I use both. No, really.

If one's intent is to connect with as many people as possible, having as many messaging/real chat apps as possible is a good idea (imo).

That's why I have WA, DC, Stoat, Signal, Matrix and IRC.

I use matrix with a bunch of my friends to replace discord and and it is quite good. The main draw for me was the awesome client options like fluffy chat, commet, and sable.

Signal is more stable & simple to set up. So for its intended use, getting people to actually talk to me on it, it's better.

Matrix is obviously better as a Discord replacement. It doesn't require a phone number which is also good. Not centrally managed so easier to decouple from big tech corruption. So it is better in those ways.

Signal. Matrix was made by Israeli spyware company Amdocs and when an employee was asked about it after the split to a UK company they pretended like Amdocs wasn't caught in multiple global spyware scandals already.

I feel uneasy about Signal being an app centralized in the USA, but it is the only one streamlined enough to be usable by non tech-savvy friends and family. I wonder if it will fall prey to Chat Control in Europe, so the time to explore alternatives will soon be upon us.

So far, I have heard of XMPP, Matrix, Delta chat and SimpleX. Never got friends to switch to XMPP or Matrix for more than one conversation, so I guess we're just f*cked.

Signal is a centralized, US-based service which requires your phone number (thus your real identity, IE name and address), has social networking graphs of everyone you talk to, and must forward that information to the US government when asked, as well as (by law) not tell you that they've been asked to do so. During the Obama era, 60 NSLs were issued for this private information every single day.

People overlook its privacy concerns for the same reason they do with apple: it has a shiny interface and is easy to use, and makes people very attached to it. Behind all that, is a surveillance network that its creators have explicitly said they do not want it to be able to run in a decentralized, private manner.

It has a long history of privacy offenses below (such as refusing to publish its server's source code for years, its reliance on other US tech services (amazon, google), US-government funding, and a US-defense-tank friendly administration) which get ignored or shouted down by many of those above. See the article below.

Why not signal.

Pretty much any alternative is better, as long as its not hosted in a five-eyes country, and especially if it doesn't require phone numbers or real identities like signal does.

I personally have been using SimpleX for friends and real life contacts, and Matrix for larger more anonymous group chats.

Do you want it to be so complicated that no one you know in real life is able to use it for more than two weeks before they make some kind of mistake or change that deletes their entire message history and identity? Matrix

Do you want a slim chance that friends and family might use it, but you have to listen to privacy nutjobs tell you your app is a CIA NSA PsyOp and you might as well cc: potus(at)whitehouse(dot)gov all your messages, it's run by an american non-profit obviously it can't be trusted? Signal

Signal. Requires little technical knowledge, other then knowing about end to end encryption and why its important

I would like to use matrix since if anything, I think its cool. But noone I know would be remotely interested.

I've been using XMPP the past two decades. I use it because I haven't found something that's better.

well what are your criteria? Asking for advice without saying what you need isn't tremendously useful and, as has happened, mostly just results in people recommending whatever they personally use for whatever reasons.

Signal requires your phone number, which is not only quite bad for privacy, but also easy to block 2FA for your government if it decides it doesn't like private chats.

Both ! Use Matrix with tech savy friends and Signal with your family

I'd go with Matrix. I use it as my main messenger and I've actually set up my own self-hosted instance. It works perfectly for both 1:1 conversations and managing my tabletop RPG groups. Voice chat through Element Call is fantastic – honestly, it's a solid alternative to Discord.

What I really appreciate is the control I get from self-hosting: I have complete autonomy over the server and data for both my personal messaging and community spaces. For RPG campaigns, the room structure and customizable permission system are ideal. The voice quality is reliable enough for long gaming sessions, and everything feels more private and independent compared to relying on Discord.

This is how I explained Matrix to my mom: its like an email address, but for chat. You can chat at me, even if we aren't using the same server, like someone can send an email from Gmail to Hotmail. She got set up and promptly went back to texting me every dang time.

Signal is more like WhatsApp, Element/Matrix is aiming to be more like Telegram or Discord.