News that WhatsApp has been sharing large amounts of highly personal data with Facebook since 2016 has led a large number of unhappy users to look for an alternative messaging app that genuinely respects their privacy.

At Proton, we view end-to-end encryption as a core requirement for any messenger app that claims to be secure and private. This means messages are encrypted on your device and can only be decrypted on the device of the intended recipient. 

WhatsApp uses end-to-end encryption, so the actual messages are therefore secure on the platform. But this does nothing to stop Facebook from abusing metadata: information about whom you communicate with, from where, at what time, how often, and from which device.

Open source code is another important indicator that a service is secure. By publishing an app’s code publicly, anyone can examine it to ensure the app is doing what it is supposed to be doing. We believe open source is one of the best indicators that an app can be trusted.

We have therefore limited the following list of best WhatsApp alternatives to open source messaging apps that use end-to-end encryption (E2EE). Please note that apps are not reviewed in any particular order.

Signal

Pro

Free
Very good encryption
Almost no metadata kept
Protocol independently audited
Seamless to use on Android
Disappearing messages
E2EE text, voice, and video group chat

Cons

Requires a valid phone number to register
Hosted on Amazon Web Services (AWS)

The Signal messaging protocol is an end-to-end messaging protocol developed by the Signal Foundation, a non-profit organization founded by cryptographer and privacy activist Moxie Marlinspike. The Signal Protocol is open source, has been professionally audited for security vulnerabilities, and is widely admired for its cryptographic strength. 

Because of the quality of the Signal protocol, it is used by a variety of third-party messaging apps to provide secure end-to-end encryption for messages. These include WhatsApp, Facebook Messenger, and Skype, Unlike WhatsApp and other third-party apps that implement the Signal protocol, however, the Signal app from the Signal Foundation is 100% open source. 

Crucially, in light of recent heightened awareness about WhatsApp’s privacy policies, the Signal app and Signal Foundation keep almost no metadata related to the app’s usage. Only “the date and time a user registered with Signal and the last date of a user’s connectivity to the Signal service.” This is a claim that has been proven in court.

The app app itself has not been audited, however, and some security concerns exist around Signal’s reliance on Intel Software Guard Extensions (SGX). In theory, this could result in users’ metadata and data(but not messages) being compromised at the server level. This is a particular concern because Signal uses AWS to host its infrastructure, which is subject to legal demand from the US government.

Unlike WhatsApp, Signal is designed to replace your phone’s regular SMS messenger app on Android (not iOS). Texts exchanged to other Signal users are end-to-end encrypted, but texts to non-Signal users are not. Signal will warn you when messages are sent unencrypted. 

This makes Signal very transparent in use, but the fact that users must register with a valid phone number in order to match contacts is also the main source of criticism the app receives. It should be noted, though, that contacts are stored locally only and cannot be accessed by Signal Foundation.

In addition to messages, Signal supports disappearing messages, E2EE group voice chats, and now group video chats between up to eight users. Signal is a non-profit organization that relies on donations to operate.

Telegram

Pros

Free
Channels for broadcasting messages
Bots for managing groups
Sync across multiple devices (not E2EE)
Polls, stickers, sharing live location, identity management
E2EE 1-1 text, voice, and video chat

Cons

Encryption concerns
Only Secret Chats are E2EE 
Group chats (text or voice) are not E2EE
Collects lots of metadata
No group video chats
Requires a valid phone number to register
Headquartered in the UAE, which is not known for human rights or privacy from the government (despite having some strong privacy laws)

With over 500 million users, Telegram is a very popular WhatsApp alternative. A big part of this popularity is the widespread perception that Telegram is highly secure, a perception only heightened by a number of governments, notably Indonesia, Russia, and Iran, trying to block or ban the app.

There are, however, some big caveats regarding the security that Telegram offers its users. Regular default “Cloud-based messages,” that can be accessed on any of a user’s devices, are encrypted in transit and when stored on Telegram’s servers, but they are not end-to-end encrypted. Only client-to-client “secret chats” are end-to-end encrypted. Secret Chats are not available for groups or channels.

The open source in-house MTProto encryption used to secure communications in Telegram (whether E2EE or otherwise) has come under criticism from security experts, although the new version (MTProto 2.0) has been formally verified to be cryptographically sound. The Telegram API and all Telegram apps are open source, but its server-side backend is not. 

Another issue is that Telegram may collect a great deal of metadata from users: “We may collect metadata such as your IP address, devices and Telegram apps you’ve used, history of username changes, etc.”

On the other hand, Telegram has built its own secure cloud infrastructure, distributed across the globe. The encryption keys used to secure the Telegram Cloud are split in pieces and never stored in the same place as the information they protect.

Security considerations aside, a key feature that contributes to Telegram’s popularity (especially in repressive countries such as Iran, where it enjoys over 40 million users despite government attempts to regulate use of the service) is support for “channels.” Users can create and post to channels that any number of other users can subscribe to. 

Public channels can be created using an alias and a URL that anyone can subscribe to, making Telegram a powerful tool for organizing resistance and disseminating information in repressive countries. 

Other features that help make Telegram popular include polls, stickers, sharing live locations in chats, and an online authorization and identity management system for those who need to prove their identity. A bots feature assists managing groups and channels. 

It also features One-to-one voice and video chats are fully end-to-end encrypted, although group voice chats are not. Group video calls are not supported.

Telegram is funded by public donations (notably from its own founder, Pavel Durov), although it is possible in-app monetization features will be introduced in the future.

Threema

Pros

No phone number or email required to sign up
Almost no metadata kept
Independently audited 
Swiss-based with own servers
GDPR compliant
E2EE group text and voice chat
Group polling and distribution lists (Android only)

Cons

Not free
Relatively small userbase
No group video calls

Like Proton, Threema is based in Switzerland, a country with very strong data privacy laws and independent from the United States and European Union. It also owns its own server infrastructure located in Switzerland. 

All Threema’s apps use the open source NaCl cryptography library for end-to-encryption of all communications, and all have been recently audited (in 2020) by security professionals. 

An email address or phone number is not required to register an account, and it is possible to purchase Threema for Android anonymously using Bitcoin. Threema claims this allows you to text and make calls anonymously, and it goes to lengths to ensure that a minimum amount of metadata is collected. 

The fact that the app is not free is likely to be a pain point for some, but at around US$3 (one-time purchase), it’s unlikely to break the bank for most. This may contribute, however, to one of the biggest downsides with Threema: that its userbase is relatively small. 

The Android app features distribution lists that allow you to send messages to multiple separate recipients. In addition to fully E2EE group text and voice calls, Threema offers a group polling feature. E2EE video calls are supported, but not for groups.

Wickr Me

Pros

Free
Built for ephemeral messaging
Anti-censorship feature
E2EE group text and voice chat
No phone number or email needed for signup

Cons

Apps themselves are not open source 
Security audits are not published
No video chat (although available on free Pro version of app)

There are three Wickr apps, with the free Wickr Me being the version designed for personal use. The lowest tier of the more Slack-like Wickr Pro is also free, although it requires you to verify your identity at start-up.

Wickr Me places ephemeral messaging front and center, with messages disappearing from both the sending and receiving devices after a set period of time (six days by default). Undelivered messages sitting on Wickr servers are also deleted after this time.

You can also set a Burn-On-Read timer to determine how long a message lasts before self-destructing once it has been read. If it is not read then it will self destruct at the end of the message timer length. All metadata is scrubbed once a message is opened or expires (whichever comes first)

Wickr advertises itself as open source software, but there are a couple of major caveats to this claim. The code for the core wickr-crypto-c end-to-end encryption protocol that underpins all Wickr apps is available on Github for anyone to examine, but licencing restrictions mean that it cannot truly be described as open source.

More serious from a security stand-point, though, is that while the core crypto protocol is source-available, the code for the Wickr apps themselves is not. Wickr says that its code has undergone multiple independent security audits, but the full results of these audits are not publicly available.

No phone number or email is needed to register with the service. Up to 10 people can be invited into a room or end-to-end encrypted text or voice group chat. Video conferencing is not available in Wickr Me, although it is supported in the Wickr Pro app (including E2EE group chat with all room members).

Wickr is hosted on public server networks (such as Google and AWS), but has partnered with Psiphon to offer Wickr Open Access, a powerful anti-censorship feature.

Wickr Me is free, but it is funded through Wickr’s premium Pro and Enterprise apps. 

Wire

Pros

Free option
E2EE text, voice, and video group chats
Syncs across up to eight devices
Advanced video conferencing features

Cons

Quite a lot of metadata logged (and possibly stored in plaintext)
Phone number or email address required to register

Wire is another service based in privacy-friendly based in Switzerland. A phone number or an email email to register. In order to facilitate syncing across multiple devices, however, Wire keeps quite a lot of metadata. 

For years Wire kept a list of all users a customer has contacted in plaintext on their servers until an account is deleted, and it is unclear if this practice continues. Wire’s privacy white paper, however, makes it clear it logs data such as the participants in a group chat and user-defined folders used for organizing chats. 

The functional benefit of this is that it allows Wire to work across multiple devices in a way most E2EE messenger apps (including Signal) do not. It’s also worth noting that Edward Snowden recommends using Wire (or Signal).

Wire uses the Proteus protocol to provide end-to-end encryption for text messages. Proteus is an early fork from the code that went on to become the Signal Protocol. Proteus, and all Wire apps, have been publicly audited (making Wire the only app we are aware of to have this done).

Voice (up to 25 participants) and video calls (up to 12 participants) are end-to-end encrypted using DTLS with an SRTP handshake.

The app does support advanced video conferencing features that will appeal to business users, though, including screen sharing, screen recording, and advanced meeting scheduling.

Wire is keen to push users toward its premium Pro and Enterprise products, but a free version is available which offers similar features to the Pro app.

Element (was Riot.im)

Pros

Free option
Server federation
“Bridges” for interoperability with other apps
E2EE text chat
No phone number or email needed for signup

Cons

Questions over Matrix server network reliability
Not fully audited

All the other messenger apps discussed in this article rely on a centralized server network to function (although, as in the case of using AWS, this can be a highly distributed network).

Element is instead built on the idea of federation. Users can set up their own servers using the Matrix communications protocol or connect to Matrix servers that have been set up by other users. Federation has received the support of Edward Snowden, but remains a controversial idea due to the potentially unreliable ad-hoc peer-to-peer nature of such a network.

Matrix servers are interoperable, so any user of any Matrix client (Element is the most popular of these) can communicate with any other Matrix user. Matrix “bridges” even allow for communication with the users of other popular messaging platforms, such as Signal, Slack, or even WhatsApp.

Matrix (and thus Element) uses the Olm implementation of the Double Ratchet algorithm, with Megolm used for group communications. All Element apps, plus the Matrix protocol itself, are open source, but have not been formally audited. Olm and Megolm, however, have.

An email or phone number is not required to register with Element, although these can be added to make contact matching easier. By default, messages are hosted on a large public server run by Matrix, but you can connect to any Matrix server or set one up yourself in a matter of seconds.

All text chats and 1:1 voice and video calls are end-to-end encrypted. Group voice and video calls ( which also allow screen sharing) leverage Jitsi ( without E2EE support in Element at the present time). The Element app is free, but premium plans are available for Element-managed Matrix servers.

Keybase

Pros

Free (funding model is unclear)
E2EE text chats with support for public and private channels
Can connect to people via their social media profiles with PGP verification
Syncs across multiple devices
Self-destructing messages
Stellar wallet
250 GB free storage per user
Encryption is not TOFU

Cons

Owned by Zoom
A lot of metadata logged (much of it shared on a public blockchain)

Keybase is a free and open source (FOSS) messenger app (servers are not open source) that end-to-end encrypts all texts and files between users. Voice and video calls are not supported directly, but are possible using a (not E2EE) Jitsi bot.

E2EE group chat, with support for private and public “Teams” (i.e., channels) is end-to-end encrypted.

Keybase is notable for allowing you to connect to others using their social media (Twitter, GitHub, Reddit, Hacker News, and Mastodon) identities, which are verified using PGP encryption keys. No phone number or email address is required, and the app will sync across multiple devices. 

The PGP-based end-to-end encryption used by Keybase is solid and underwent a full independent audit in 2019. Interestingly, Keybase is almost unique in not supporting Trust On First Use (TOFU) when connecting to servers. This helps to make it resistant to man-in-the middle attacks.

The app also offers self-destructing messages; bots to automate your Keybase tasks; a Stellar wallet; full PGP support for encrypting and decrypting messages and files; and 250 GB free storage per user.

However, messages are stored on centralized servers (based in the US), which log a worrying amount of personal data. This includes your Team names and memberships, hashed passwords, account activity, your Keybase user ID and your IP address, network activity, and more. Not only is information stored encrypted, but much of it is added (in hashed form) to a public blockchain.

Arguably even more concerning is that Keybase is now owned by Zoom, a company widely criticized for its many privacy and security lapses, and which may be subject to pressure from the Chinese government. The fact that it is not clear how Zoom benefits from offering Keybase for free may also be a reason for concern.

Final thoughts

As a replacement for WhatsApp as a general purpose messenger that genuinely respects your privacy, Signal is an obvious choice, although being hosted on AWS servers remains a concern in light of its reliance on SGX. The security concerns around Telegram make it harder to recommend as a simple messenger, although its “channels” feature remains a powerful tool for organizing resistance in restrictive countries.

Another alternative for secure communication is end-to-end encrypted email. The biggest benefit of ProtonMail is its interoperability: You don’t need to have your recipient using the same messenger service to benefit from end-to-end encryption because, unlike any of the messenger apps discussed here, you can send end-to-end encrypted messages to anyone who has an email address using our Encrypt for non-ProtonMail users feature. The simplest way to benefit from E2EE, though, is to have both ends of the conversation using ProtonMail. Our servers are located in privacy-friendly Switzerland, and as with the messenger services discussed in this article, ProtonMail apps are open source.

The other apps discussed above all offer useful features that will appeal to those who need them, whether it’s anonymous sign-up, business collaboration tools, or server federation. Element/Matrix is a particularly strong choice for privacy enthusiasts, although its niche user base severely hampers its practicality as as a WhatsApp replacement.

As you take back your privacy in the digital age, anything you do to move more of your personal data behind strong encryption is an important step toward building an internet that puts people first.

FAQ

What are the dangers of using WhatsApp?

Since 2016, WhatsApp has shared the vast majority of its users’ transactional data and metadata with Facebook. A new privacy statement, which users must agree to by May 15, 2021, or use access to their accounts, “clarifies” this situation.

Information shared by WhatApp with Facebook includes your IP address, device ID, operating system, browser details, mobile network information, who you message, how long and how often you interact with them, transaction and payment data, and more.

Is WhatsApp chat private?

Messages in WhatsApp are end-to-end encrypted using the Signal protocol. This means only you and the intended recipient(s) can read your actual messages. So WhatsApp is secure. It does, however, collect a lot of metadata that is damaging to your privacy (see above).

What is the safest messaging app?

Signal is both highly secure and respects your privacy. We discuss it, plus the pros and cons of other good WhatsApp alternatives, in this article. 

How can WhatsApp be free?

WhatsApp is owned by Facebook, which makes a huge amount of money from invading users’ privacy in order to better target you with personalized ads. WhatsApp adds to the data Facebook knows about you by sending a great deal of metadata regarding your use of WhatsApp to Facebook. 

Note that, as Signal and some of the other apps discussed in this article, show, it is possible to offer a free messaging app without invading users’ privacy in this way.

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Footnotes:

All Telegram apps are open source, but the backend isn’t. This would not really be an issue if all communications were E2EE, but they are not by default (and no group chat is E2EE).
By default, Telegram chats are not end-to-end encrypted. Only client-to-client “secret chats” are. Secret chats are not available for groups or channels.
The 2015 audit of MTProto protocol was not very favorable. MTProto 2.0 has been formally verified to be cryptographically sound.
Wickr says its code has undergone multiple independent security audits, but the full results of these audits are not publicly available.
The Element apps and the Matrix protocol have not been formally audited. However, the Olm and Megolm protocols that underpin Matrix have.
All metadata is scrubbed once a message is opened or expires (whichever comes first).
Contacts can be added using social media profiles and verified using PGP keys.
Wickr has partnered with Psiphon to offer Wickr Open Access, a powerful anti-censorship feature for its servers.
Element and/or Matrix don’t actually own their own servers, but new Matrix servers can be set up within minutes on any server platform (or can be self-hosted). It is therefore almost impossible to shut down or block access to the Matrix platform. 
Wire is based in Switzerland and all users outside the United States are subject to Swiss law. US users, however, are subject to US law.
Matrix is a community-developed open source platform whose federated servers can be hosted anywhere in the world. 
Keybase is owned by Zoom, which may also be subject to pressure from China.

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