How to choose a private messenger: 7 questions worth asking
Almost every messenger calls itself private. The word costs nothing, because it can hide completely different things: one app encrypts only the network connection, another keeps your messages unreadable even to its own servers, and a third simply does not show ads. The seven questions below pull those cases apart. The answers are usually somewhere in the documentation, and when they are not, that is an answer too.
1. What is encrypted, and from whom
Encryption happens in three different places, and they get confused constantly. The difference matters, because it decides who could in theory read your conversations.
The strictest model, end-to-end encryption, means the keys live only on the participants' devices and the server physically cannot decrypt a message. That is how Signal and WhatsApp work. In Chattr, messages are encrypted in transit and on the server, but this is not end-to-end encryption: we do not use conversations for advertising and do not share them with third parties, yet Signal's model is stricter. If end-to-end is a hard requirement for you, the honest answer points to Signal.
- Transport encryption (TLS): protects against anyone listening between you and the server. Nearly universal, ordinary websites have it too.
- Encryption at rest: data sits on the server's disks encrypted. Helps if a disk is stolen, but the service holds the keys.
- End-to-end encryption (E2EE): only the participants hold keys, and the server cannot decrypt even if it wanted to.
2. What you have to hand over to sign up
A phone number is usually tied to your legal identity, your bank card and a dozen other services. A messenger that requires one knows who you are regardless of how well it encrypts messages. It can also find you by number in other people's address books, so your account surfaces to people you never gave it to.
Chattr sign-up is anonymous and needs no phone number. That does not make Chattr cryptographically safer than Signal, but it removes the most obvious link between an account and a person.
3. What metadata is left behind
Even when message content is sealed properly, a layer of data remains around it: who contacted whom, when, how often, from which IP address, how large the attachment was. That layer reconstructs a great deal, sometimes more than the text itself would.
So the useful question is not “do you encrypt messages” but “what do you keep about the fact that a conversation happened, and for how long”. We wrote about this separately in the article on metadata.
4. What happens when the network is filtered
Privacy is worthless if the app will not open. On networks that filter traffic, messengers stop connecting, slow to a crawl or lose media delivery, and the usual answer, install a VPN, does not always hold: VPNs get blocked too, they drain the battery, and they require trusting one more intermediary.
Chattr is built to stay reachable on those networks without a separate VPN. That is its core job and the main reason people use it alongside cryptographically stricter alternatives.
5. Is the source code open
Open source lets independent specialists verify that an app does what it claims. It is a strong argument, and Chattr loses this one: our code is closed. Signal publishes both client and server, so if independent verifiability is critical to you, that counts in its favour.
Worth remembering, though, that open source is not the same as secure: what matters is whether an audit happened, who ran it, and whether the published code matches the build that actually ships in the app store.
6. How the app makes money
A free product always has a revenue source, and that source sets its incentives. If it is advertising, the app benefits from knowing more about you. If it is a subscription or donations, it earns when you are satisfied rather than when you have been profiled more precisely.
Chattr is free, and the optional Pro subscription costs 150 RUB a month, which pays for servers and development. There are no ads, no trackers, and no data sales.
7. What happens to your data if you leave
Good sign: the service has a clear page about deleting your account, and it is not hidden. Bad sign: deletion only happens through a support conversation and no timeframe is stated anywhere.
Check this before you move your conversations in, not afterwards. Chattr documents account and data deletion on a dedicated page.