Comparison of secure instant messengers

[JohnnyDoe]

When privacy, censorship resistance, and decentralization matter, the usual mainstream messengers won’t cut it. Instead, a number of privacy-first, often federated or decentralized instant messaging apps have emerged. Below is a comparison of the most relevant ones.

SimpleX​

• A radically different model—no user ID, no accounts. Communication is routed via intermediaries without exposing metadata.
• No central server, completely anonymous.
• Built around the Signal encryption protocol but avoids contact lists or phone numbers.

XMPP (with Conversations)​

• A protocol from 1999, revitalized through modern clients like Conversations on Android.
• Federated architecture, with OMEMO encryption.
• Mature, widely supported, and easy to self-host.

Delta Chat​

• Uses the email infrastructure (IMAP/SMTP) to send encrypted messages via OpenPGP.
• If you have email, you already have Delta Chat—no additional servers needed.
• Technically federated by nature of email.

Matrix (with Element)​

• A modern, federated real-time communication protocol.
• Uses end-to-end encryption via Olm and Megolm.
• Supports everything from simple chats to full VoIP and bridges to other networks.

Session​

• Forked from Signal, but built on a blockchain-based, decentralized network.
• Requires no phone number or email to use.
• Metadata-resistant and designed for anonymity.

Messenger	Year	Architecture	Encryption	Federation/Decentralization	Self-Hostable	Unique Traits	Platforms
SimpleX	2021	Decentralized (relay-based)	Signal (modified)	✅ Full decentralization	✅	No IDs, no metadata, no contact list	Android, iOS, desktop
XMPP (Conversations)	1999 / 2014	Federated (XMPP protocol)	OMEMO	✅ Federated	✅	Mature, modular, server-agnostic	Android, iOS, desktop
Delta Chat	2017	Email-based	OpenPGP	✅ Via email infrastructure	✅ (email)	Uses existing email accounts	Android, iOS, desktop
Matrix (Element)	2014 / 2016	Federated	Olm/Megolm	✅ Federated	✅	Bridging to Slack/Telegram/IRC etc.	Android, iOS, desktop
Session	2020	Decentralized (blockchain)	Signal (fork)	✅ Blockchain node-based	⚠️ Only with staking	Fully anonymous, no phone/email	Android, iOS, desktop

 

[CEO]

I would like to add :

Network protection layer: Next DNS / nym Mixnet for both financial and personal use.

Mobile protection layer: GrapheneOS only for specific devices.

Desktop protection layer: Qubes OS has some hardware support limitations.

 

[JohnnyDoe]

I would like to add :

Network protection layer: Next DNS / nym Mixnet for both financial and personal use.

Mobile protection layer: GrapheneOS only for specific devices.

Desktop protection layer: Qubes OS has some hardware support limitations.

better to discuss these in dedicated threads

 

[CEO]

better to discuss these in dedicated threads

I mentioned it here because of the complex sophisticated relationship.

 

[GuaraniGhost]

I would like to add :

Mobile protection layer: GrapheneOS only for specific devices.

I read that GrapheneOS will lose access to immediate updates to changes announced by Google when Android 16 is released.

 

[CEO]

I read that GrapheneOS will lose access to immediate updates to changes announced by Google when Android 16 is released.

They will find a way to fix it.

GrapheneOS Frequently Asked Questions

Answers to frequently asked questions about GrapheneOS.

grapheneos.org

 

[Marty McFly]

I like ElementX (Matrix), nice UI

 

[WhoMe]

Session is in trouble:
x.com/session_app/status/2034446033732968901#m

 

[Morpheus]

Session in trouble again.
What about Threema? Since many many years one of my preferred platforms, next to signal with a random number + session

 

[Marty McFly]

I don’t think session will close

 

[chicharito]

Here's a good article on why Signal sucks if you're running extra-curricular activities on the side (SimpleX is better): https://bible.beginnerprivacy.com/opsec/signalnoanonymity/

 

[WhoMe]

Given Session's problems, I'm looking elsewhere but to my horror, SimpleX doesn't encrypt calls. WHAT! That's a serious shortcoming.

If Signal switches to usernames and no phone number required, that will be enough for me if Session folds.

 

[JohnnyDoe]

elementX seems the best alternative so Session

 

[WhoMe]

Given Session's problems, I'm looking elsewhere but to my horror, SimpleX doesn't encrypt calls. WHAT! That's a serious shortcoming.

If Signal switches to usernames and no phone number required, that will be enough for me if Session folds.

I should probably clarify what I said about SimpleX not encrypting calls. It only does it for compatible phones. Someone I called has an older model Galaxy and his phone is "too old" to encrypt the call. Signal, Session, even WhatsApp can encrypt the call regardless of the model of phone. So that's something SimpleX must fix.

 

[CEO]

I should probably clarify what I said about SimpleX not encrypting calls. It only does it for compatible phones. Someone I called has an older model Galaxy and his phone is "too old" to encrypt the call. Signal, Session, even WhatsApp can encrypt the call regardless of the model of phone. So that's something SimpleX must fix.

GraphenOS response is good enough :

Why are older devices no longer supported?
GrapheneOS aims to provide reasonably private and secure devices. It cannot do that once device support code like firmware, kernel and vendor code is no longer actively maintained. Even if the community was prepared to take over maintenance of the open source code and to replace the rest, firmware would present a major issue, and the community has never been active or interested enough in device support to consider attempting this. Unlike many other platforms, GrapheneOS has a much higher minimum standard than simply having devices fully functional, as they also need to provide the expected level of security. It would start to become realistic to provide substantially longer device support once GrapheneOS controls the hardware and firmware via custom hardware manufactured for it. Until then, the lifetime of devices will remain based on manufacturer support. It's also important to keep in mind that phone vendors claiming to provide longer support often aren't actually doing it and some never even ship firmware updates when the hardware is still supported by the vendors...

GrapheneOS Frequently Asked Questions

Answers to frequently asked questions about GrapheneOS.

grapheneos.org

-

Tech Spec:

WebRTC uses two pre-existing protocols, Datagram Transport Layer Security (DTLS) and the Secure Real-time Transport Protocol (SRTP).

Ref. Securing

SimpleX Chat allows you to make end-to-end encrypted audio and video calls with your contacts via WebRTC. Note: Group calls are not supported at this time.

Ref. Audio & video Calls

SRTP in WebRTC

Ref. SRTP in WebRTC

WebRTC. All of the WebRTC related protocols are required to encrypt their communications using DTLS; this includes SCTP, SRTP, and STUN.

Ref. DTLS (Datagram Transport Layer Security) - Glossary | MDN