It is not a matrix client. I haven't dug too deep into their system, but it looks to me like a centralized server with additional steps (ie. still a single entity owning the server infrastructure)

From what I read in their documentation[1], session's network is built upon an onion routing system where nodes are registered in the OXEN blockchain; you stake 15000 $OXEN to create a node and if you are "well-behaved" you get rewards in that blockchain -- otherwise you lose your stake.

I haven't dug too deep but it doesn't sound much more centralized than the tor network for example.

[1] https://docs.oxen.io/products-built-on-oxen/session/network-...

That's a good thing. Forcing people to give their phone number to use an instant messaging app/protocol is a sign the company just wants your private data.

Also, by doing that and letting the account existence be publicly known, anyone with their phone number will know that they have an account on that service and lets you try to contact them. That can range from privacy violation to life-in-danger situations.

I adamantly refuse to register for accounts that require my phone number unless it's for commercial or official purposes. The likes of Google, Facebook and Microsoft can go take a long walk off a short plank.

We give too much information away. Companies have shown that they are incapable of keeping the information private anyway. We get big scandals, the interwebs kick up a big stink, brows are furrowed, and then we go back to doing what we did before with nobody learning anything.

I agree with you when it comes to random apps, but messengers are probably the only exception where I accept it.

If I gave my phone number to someone, I made an implicit social contract with that person or organization that they may contact me using that phone number. I don't see it as a big stretch if they use that number to send me a message or call me using WhatsApp, Signal or any other messenger where I registered using that same number. It's for the same purpose of communication, after all.

If I don't want to be contacted, I just don't share that number.

And it's not like people don't know that messengers or social networks can collect contact metadata about messages and calls. It's what traditional landline and mobile providers have been doing for ages.

I find phone numbers awesome because you actually "own" them to some degree. (i.e. you can take your number to a new provider). Moving to a different messenger app with the same phone number means I can at least still find some of my network there. Only email on your own domain would have that feature.

I don't really care if they sell my phone number, it's already out there, I don't consider it private data anymore.

Quite true. It would be better, though, to be able to use an instant messaging system using a simple identifier lie an e-mail address, as an alternative to a phone number. Simply because there are quite some people out there who mainly want to message on a computer, and want to keep only some kind of messages on their phones.

Delta Chat.

It’s basically an email client disguised as a messenger.

"Convenience, not privacy!"

It's a fork of the Signal client but instead of the centralized Signal back end, uses the decentralized Oxen Service Node system to relay messages.