Comparison of Instant Messengers

There are probably a hundred or more different instant messengers out there. But which one respects your privacy, is resistant to censorship attempts by governments and Big Tech, and is easy to use for normies?
I have limited this comparison to only ten messengers:

• XMPP, the pioneer of FOSS and federated instant messengers. XMPP is just a protocol and not an application; in this article it is represented by the Android app Conversations.
• Delta Chat, which is based on normal email and hence has the greatest theoretical userbase among all federated messengers.
• Matrix, a new and very promising federated protocol, here represented by the leading client Element.
• Signal, the most mainstream end-to-end (E2E) encrypted FOSS messenger.
• Telegram, the most mainstream FOSS messenger, and market leader in some countries.
• Threema, the most mainstream E2E-encrypted FOSS messenger with the option of anonymous accounts.
• Facebook Messenger, the second most popular messenger worldwide.
• Line, the most popular messenger in Japan, Taiwan, and Thailand.
• Viber, as it is the most popular messenger in some countries.
• WhatsApp, the #1 most popular messenger worldwide.

Some messengers that are relevant but did not make it on the list:

• iMessage (+FaceTime): not available on Android
• RCS (Google Messages): not available on iOS
• Anything else made by Google: Google Chat, Google Meet, Google Duo, Google Hangouts, it's hard to follow what they're pushing at the moment. They keep deprecating and reinventing their IM apps. It's too tiresome to follow and they won't ever make a breakthrough anyway. Should have kept Google Talk, which was simply an XMPP client.
• Skype: Not market leader in any country (anymore), cannibalized by Microsoft Teams
• Briar: Peer-to-peer messenger with the most mindshare, but low adoption, limited functionality (only text messages), not available for iOS
• Tox: Another well-known P2P messenger, supports more platforms than Briar, but low adoption.
• ICQ: One of the first, and historically very popular, IMs. It's still around but with a small number of active users.
• WeChat: The market leader in China, and third most popular IM worldwide, but it's a privacy nightmare and there's no reason to use WeChat if you're not Chinese or living in China.
• KakaoTalk: The market leader in South Korea, but low adoption elsewhere.
• IRC: A protocol with many clients and server federation. Unlike XMPP for example, IRC focuses mostly on group chats rather than 1:1 instant messaging.
• Discord: Quite popular, but mostly focuses on group and voice chats. Privacy nightmare.
• Kik: Quite popular, but not #1 anywhere
• Snapchat: Quite popular, but more like a social media than pure IM, and not #1 in any country.
• QQ: Second most popular messenger in China. But if WeChat doesn't make it on list, QQ won't make it either.
• Wire, Wickr, Slack, Microsoft Teams, BBMe, Mattermost: Focus on enterprise users.
• Jami, Session: Low adoption.
• Instagram, LinkedIn: Mainly social media rather than a messenger.
• Mumble, Teamspeak: Voice chat focus.

Comparison of Instant Messengers

Source: eylenburg.github.io

Last updated: April 2023

	Federated & FOSS			Centralized & FOSS			Proprietary Market Leaders
	Conversations (XMPP)	Delta Chat	Element (Matrix)	Signal	Telegram	Threema	Facebook Messenger	Line	Viber	WhatsApp
General information
Year introduced	2014 (XMPP: 1999)	2017	2016 (Matrix: 2014)	2014	2013	2012	2011	2011	2010	2009
Developer	mainly Daniel Gultsch	various developers	The Matrix.org Foundation CIC	Signal Technology Foundation	Telegram FZ LLC	Threema GmbH	Facebook, Inc.	LINE Corporation	Rakuten Group, Inc.	Facebook, Inc.
Domicile of developer	Germany	n/a	UK	USA	UAE	Switzerland	USA	Japan	Japan	USA
Monthly active users	n/a cannot be determined due to server federation	n/a cannot be determined due to server federation	n/a cannot be determined due to server federation	40 million	550 million	10 million	1.3 billion	250 million	825 million	2.0 billion
Play Store number of installs	100,000+refers only to the Conversations app, which is only one of many XMPP messengers	100,000+	500,000+refers only to the Element app, which is only one of many XMPP messengers	50,000,000+	500,000,000+	1,000,000+	5,000,000,000+	500,000,000+	1,000,000,000+	5,000,000,000+
Protocol used	XMPP + OMEMO	IMAP/SMTP + OpenPGP	Matrix + Olm/Megolm	Signal	MTProto	NaCl + Ibex	MQTT + Signal	MQTT + Letter Sealing	Viber	XMPP + Signal
Price	freeFree download on F-Droid. Play Store costs €2.99. Alternatively, Quicksy (same developer, almost identical app) is free on the Play Store as well.	free	free	free	free	€3.99	free	free	free	free
Sustainability
License of client/server	GPL	GPL	Apache	GPL	GPL/Proprietary	AGPL/Proprietary	Proprietary	Proprietary	Proprietary	Proprietary
Server architecture	Federated	Federated	Federated	Centralized	Centralized	Centralized	Centralized	Centralized	Centralized	Centralized
Ability to self-host server	Yes	Yes	Yes	No	No	No	No	No	No	No
Compatibility with other messengers	Yes, if supported by server "Transports" to various other protocols and messengers, e.g. IRC, SMS, Email, WhatsApp, Facebook Messenger, Telegram, Skype, Discord	Normal Email if recipient does not use Delta Chat	Yes, if supported by server "bridges" to various other protocols and messengers, e.g. IRC, SMS, Email, XMPP, WhatsApp, Facebook Messenger, Apple iMessage, Telegram, Signal, Skype, Discord, WeChat	No (SMS in earlier Android versions)	No	No	Instagram; Android app can send/receive SMS	No	No	No
Compatibility
Smartphones:
Android	Yes (APK available)	Yes (APK available)	Yes (APK available)	Yes (APK available)	Yes (APK available)	Yes (APK available)	Yes (no APK available)	Yes (APK available)	Yes (no APK available)	Yes (APK available)
iOS	Other XMPP client(s)	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
KaiOS	No	No	Other Matrix client(s)	No	Other Telegram client(s)	No	Older versions of KaiOS	No	No	Older versions of KaiOS
Mobile GNU/LinuxMobile distributions such as Sailfish OS, Ubuntu Touch, postmarketOS etc.	Other XMPP client(s)	Other Delta Chat client(s)	Other Matrix client(s)	Other Signal client(s)	Other Telegram client(s)	Can run Android versionusing Anbox (most distributions) or Sailfish X Android App support	Can run Android versionusing Anbox (most distributions) or Sailfish X Android App support	Can run Android versionusing Anbox (most distributions) or Sailfish X Android App support	Can run Android versionusing Anbox (most distributions) or Sailfish X Android App support	Can run Android versionusing Anbox (most distributions) or Sailfish X Android App support
Desktops:
Windows	Other XMPP client(s)	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
macOS	Other XMPP client(s)	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
GNU/Linux Desktop distributions such as Ubuntu, Debian, OpenSUSE, Fedora etc.	Other XMPP client(s)	Yes	Yes	Yes	Yes	Yes	Can run Android versionusing Anbox	Can run Android versionusing Anbox	Yes	Can run Android versionusing Anbox
Unix e.g. FreeBSD, OpenBSD, NetBSD, DragonFlyBSD, Illumos, and Solaris	Other XMPP client(s)	No	Other Matrix client(s)	No	FreeBSD FreeBSD has a port of the standard Telegram app / other client(s)For other Unix operating systems	No	No	No	No	No
Web client	Other XMPP client(s)	No	Yes	No	Yes	Yes	Yes	Chrome extension	Yes	Yes
Capability
Offline messages (if recipient is offline)	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Group chats	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Voice messages	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Voice and video calls	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Send photos, video and other files	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Screensharing	No	No	Yes (not on mobile)	No	Yes	No	Yes (not on mobile)	Yes (not on mobile)	Yes (not on mobile)	No
Public/searchable groups	Yes	No	Yes	No	Yes	No	No	No	Yes	No
Ephemeral (self-destructing) messages	Only on local deviceAutomatic message deletion on local device, but no remote deletion on other people's devices	No	No	YesPlease note that this doesn't truly protect messages from being saved or read by other parties. See: https://www.freie-messenger.de/en/begriffe/pseudosicherheit/	YesPlease note that this doesn't truly protect messages from being saved or read by other parties. See: https://www.freie-messenger.de/en/begriffe/pseudosicherheit/	No	YesPlease note that this doesn't truly protect messages from being saved or read by other parties. See: https://www.freie-messenger.de/en/begriffe/pseudosicherheit/	YesPlease note that this doesn't truly protect messages from being saved or read by other parties. See: https://www.freie-messenger.de/en/begriffe/pseudosicherheit/	YesPlease note that this doesn't truly protect messages from being saved or read by other parties. See: https://www.freie-messenger.de/en/begriffe/pseudosicherheit/	YesPlease note that this doesn't truly protect messages from being saved or read by other parties. See: https://www.freie-messenger.de/en/begriffe/pseudosicherheit/
Delete messages on device of recipients	No	No	No	Yes	Yes	No	Yes	No	Yes	Yes
Use with multiple accounts	Yes	Yes	Other Matrix client(s)	No	Yes	No	No	No	No	No
Usability
Find contacts from phone address book	supported by other XMPP clients e.g. Quicksy, from the same developer as Conversations and mostly identical	No	Phone number & Email	Phone number	Phone number	Phone number & Email	Phone number & EmailCan upload address book to Facebook to check if contacts have a Facebook account	Phone number	Phone number	Phone number
Automatic backups of chat history	Chat history is saved on the XMPP server, but useless without decryption keys, which some other XMPP clients can back up automatically (Con­ver­sations: only manual backups to local device).	Local backups of chat history are possible but not automatic. Chat history is saved on the Email server, but useless without decryption keys, which need to be manually backed up to local device.	Chat history is saved on the Matrix server, but useless without decryption keys, which can be automatically backed up to local device or Matrix homeserver	Backup on local device only (no cloud backup which would protect against loss of device)	All data is saved on Telegram servers, except for "secret chats"	No	All data is saved on Facebook servers, except for "secret chats"	Backup to cloud only (Google Drive/iCloud), and text messages only	Backup to cloud only (Google Drive/iCloud)	Yes (local device or Google Drive/iCloud)
Data can be transferred to new device	Yes (at least to new installation of Conversations)	Yes	Yes	Yes, but only Android ↔ Android or iOS ↔ iOS, not supported on Desktop	Yes, except for secret chats	Yes, but only Android ↔ Android or iOS ↔ iOS, not supported on Desktop	Yes	Text messages only, and only Android ↔ Android or iOS ↔ iOS, not supported on Desktop	Yes, but only Android ↔ Android or iOS ↔ iOS, not supported on Desktop	Yes, also between Android and iOS using "Move to iOS" and "Switch to Android" apps
Use on multiple devices	Yes	Yes	Yes	Yes, but only one Android/iOS device (but: can have linked iPad)	Yes, except for "secret chats"	Yes, but only one Android/iOS device	Yes, but "secret chats" are unavailable on desktop/web	Yes, but only one Android/iOS device	Yes, but only one Android/iOS device	Yes (needs a "primary device" running Android or iOS)
Import chat history from other apps	No (from other XMPP clients only)	No	No (from other Matrix clients only)	No (SMS import possible in earlier versions)	Yes (KakaoTalk, Line, WhatsApp)	No	Yes (SMS import on Android)	No	No	No
Privacy
User ID	XMPP address (user@server.tld)	Email address (user@server.tld)	Matrix ID (@user:server.tld)	Phone number	Phone number or "Fragment" number	Threema ID (8-digit ID)	Email address of Facebook account	Phone number	Phone number	Phone number
Anonymous sign-up possible	Yes	Yes	Yes	Phone number requiredCould use a "burner SIM" for anonymous sign-up, but in many countries it is not legal to sell/buy SIM cards anonymously	Possible with "Fragment" number (paid)Has to be paid with "TON" cryptocoin. Alternatively, can sign up with phone number.	Yes if purchased anonymously Android license can be purchased from Threema directly using Bitcoin, while the iOS app can only be bought in the App Store (hence the latter is only anonymous if the Apple ID itself is anonymous, i.e. anonymous email address used to sign up and no phone number given)	Facebook requires real identity to sign upThis may even include a video recording of the user's face to verify identify	Phone number requiredCould use a "burner SIM" for anonymous sign-up, but in many countries it is not legal to sell/buy SIM cards anonymously	Phone number requiredCould use a "burner SIM" for anonymous sign-up, but in many countries it is not legal to sell/buy SIM cards anonymously	Phone number requiredCould use a "burner SIM" for anonymous sign-up, but in many countries it is not legal to sell/buy SIM cards anonymously
E2Eend-to-end encryption of 1:1 text messages	Yesif supported by recipient's client app	Yesif recipient is also using Delta Chat, other will be sent as unencrypted email	Yesif supported by recipient's client app	Yes	Only in "secret chats"	Yes	Only in "secret chats"Impossible to verify as app is closed source	Yes (claimed)Impossible to verify as app is closed source	Yes (claimed)Impossible to verify as app is closed source	Yes (claimed)Impossible to verify as app is closed source
E2Eend-to-end encryption of group chats	Yesif supported by recipient's client app	Yesif recipient is also using Delta Chat, other will be sent as unencrypted email	Yesif supported by recipient's client app	Yes	No	Yes	Only in "secret chats"Impossible to verify as app is closed source	Yes (claimed)Impossible to verify as app is closed source	Yes (claimed)Impossible to verify as app is closed source	Yes (claimed)Impossible to verify as app is closed source
E2Eend-to-end encryption of voice and video calls	Yesif supported by recipient's client app	Yes	Yesif supported by recipient's client app	Yes	Yes	Yes	Yes (claimed)Impossible to verify as app is closed source	Yes (claimed)Impossible to verify as app is closed source	Yes (claimed)Impossible to verify as app is closed source	Yes (claimed)Impossible to verify as app is closed source
E2Eend-to-end encryption of chat backups	Yes	Local backups: no, on email server: yes	Yes	Yes	No ("secret chats" not backed up)	Yes	No ("secret chats" not backed up)	?	No	Optional, therefore pointlessE2EE for backups is an optional feature. Unless ALL parties in a chat have it enabled, the backup can be accessed by Google, Apple, governments etc. Furthermore, device-level backups on iPhone will store the unencrypted chats in iCloud. See here.
Minimal metadata	No	No	No	Yes	No	Yes	No	No	No	No
Security
Encryption: Authentification of contacts	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Encryption: Forward secrecy	Yes	No	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Encryption: Plausible deniability	Yes	No	Yes	Yes	?	No	Yes	?	Yes	Yes
Lock app with password/biometrics	No	No	No	Mobile apps only	Yes	Yes	No	No	Desktop app only	Yes

So, what's the conclusion?

• In an ideal world, everyone would use federated messengers, so that no company has the power to ban users or sell out to a Big Tech oligopolist such as Meta, Apple, Google, Microsoft, or Amazon, and so that people can self-host their own servers and thereby circumvent censorship attempts.
  • At the moment, Matrix seems to be the most promising. It has decent client apps across all major platforms, supports all the important features, and has optional contact discovery.
  • XMPP has a very lightweight and easy to set up server software. Furthermore it is a standardized protocol that has been around since 1999 and is the basis for other messengers such as Whatsapp. The main problem with XMPP is the fact that there isn't any client app which works across all major operating systems and has implemented all the important features (such as video calling). I believe that this is a roadblock to more widespread adoption among the less technologically inclined ("Oh you have an iPhone? Then you need to download Siskin, not Conversations.").
  • Delta Chat has the advantage that everyone already has an email address so there are billions of potential users which already have each other saved in their address books. However, the email protocol has its own limits, for example you can't conduct voice or video calls. Because of this, I don't think that Delta Chat will have a realistic chance of ever replacing WhatsApp.
• Signal is the next best choice. It has the best privacy out of all major messengers (XMPP and Matrix leak metadata, Signal doesn't), it can be used as the default SMS app on Android which is a huge selling point when trying to get friends and family to install it,^{not anymore} and its interface and setup are familiar to anyone who has used WhatsApp. However, Signal needs your phone number, so you can't sign up anonymously if your country forbids the anonymous purchase of SIM cards. Otherwise, the main downside is that Signal is using centralized servers, hence there is always a risk that Signal will be acquired by a privacy-hostile company. Furthermore, the Signal developers do not allow third-party clients, so users of niche operating systems are excluded.
• Telegram has lots of features and encourages the development of third-party clients. It's probably the best messenger if you don't care too much about privacy. The main downside is that chats are not E2E encrypted by default, and the E2E encrypted secret chats don't sync across devices. Furthermore, it is centralized and was forced to censor in the past (e.g. in 2022 they blocked over 60 public channels for German users after being threatened by the German government).
• Threema is good from a privacy perspective and allows users to sign up without giving up their phone number. The main problem I see is that the app costs money. It's not much, and it's good to know how the development is financed, but it is a major showstopper for widespread adoption.
• Among the big proprietary messengers, Whatsapp, Line and Viber E2E-encrypt all messages by default, which is great. However, you can never be sure that the company or the government doesn't hold the keys to access your messages, as the apps are closed source and can't be audited. Furthermore, the cloud chat backups of the proprietary messengers are not E2E encrypted. If backups are not end-to-end encrypted, then even if you don't upload your chat history to the cloud, your conversation partner may do so, and this effectively makes the rest of the E2E encryption pointless, because Apple/Google and the US government can read your messages in the cloud backup. WhatsApp offers E2EE for backups as an optional feature, however unless all parties in a chat have it enabled, this encryption can be circumvented. Furthermore, device-level backups on iPhone will store the unencrypted Whatsapp chats in iCloud unless the user has enabled "advanced data protection" (E2EE device backup) which is an opt-in feature. Hence it is more likely than not that your conversation partner has an unencrypted chat backup in a cloud somewhere and that ultimately WhatsApp's end-to-end encryption is just privacy theatre if someone "serious" (like the US government) wants to see your chats.