How to choose a messaging app: encryption, numbers, groups

Choose a messaging app by four things: whether it encrypts chats by default, who you need to reach, which devices you use, and what it asks for when you sign up. Signal, WhatsApp and Threema encrypt personal chats by default. Telegram's regular chats are not end-to-end encrypted, and only its Secret Chats mode is. The messaging apps ranking orders the options, and the points below explain how to read them.

Encryption by default

Encryption by default matters more than encryption in a special mode, because a mode you have to start is easy to forget. Signal encrypts chats and calls by default, and its client code is published. WhatsApp encrypts personal chats and calls by default, and its client is closed source. Threema also encrypts chats and calls by default. Element encrypts rooms and calls and is built on the open Matrix network. The ranking describes Apple's Messages as end-to-end encrypted for iMessage conversations.

Telegram works differently. Its regular chats are stored in the cloud and sync to every device, so they are not end-to-end encrypted. Secret Chats are end-to-end encrypted, but they are a separate mode with fewer features. If you use Telegram for private conversations, start a Secret Chat for each one you want protected.

To understand what the term covers and what it does not, read what end-to-end encryption means.

Phone numbers, metadata and anonymity

Many messaging apps tie your account to a phone number. WhatsApp's listing says its accounts are tied to a phone number on the mobile app. Signal's desktop apps work only after you set up the phone app, according to its listing. Threema can be used anonymously, with minimal metadata, and its listing describes use without personal data.

iMessage works only between Apple devices, and standard text messages reach everyone else. Before you commit, check what each app asks for when you sign up, and whether you can use it on a second device without your phone.

Metadata is the next question. Encryption protects what you write. It does not necessarily hide who you talk to, when, how often or from where. That information is called metadata. Threema's listing describes minimal metadata, which is the vendor's own claim, so check its documentation for detail. For the other apps, read each privacy policy to see what the company collects, and assume that servers can see some metadata unless the vendor describes a design that avoids it.

Groups, calls and reach

Reach often decides the choice. The ranking says WhatsApp and Telegram reach the most contacts. iMessage reaches only other Apple users, and SMS reaches everyone else. Signal reaches only people who have installed it, which keeps its reach smaller than WhatsApp's.

Group features differ. Telegram groups hold up to 200,000 members, and it has public channels. WhatsApp offers group chats with voice and video calls. Signal offers group chats with voice and video calls, and Element offers end-to-end encrypted rooms and calls. In a mixed group with Apple and non-Apple users, Messages falls back to SMS, according to the ranking.

Backups and message history

The listings here do not describe backup options for most of the apps, so do not assume one exists. Two details are documented. Telegram syncs chats across phone, desktop and web, which means its regular chats live on its servers. Apple's Messages can recover deleted messages and whole conversations, according to its listing.

Before you rely on an app as a record of conversations, check the vendor's help pages for three things: whether backups exist, whether they are encrypted, and who can restore them.

Platforms, cost and client code

Check your devices first. The table summarizes the platforms and cost each listing shows.

App	Platforms listed	Cost	Client code
Signal	Android, iOS, iPadOS, Windows, macOS, Linux	Free, funded by donations	Published, AGPL-3.0
WhatsApp	Android, iOS, macOS, Windows, web	Free, data charges may apply	Closed source
Telegram	Android, iOS, iPadOS, Windows, macOS, Linux, web	Free, no subscription needed	Published
Apple Messages	iOS, iPadOS, macOS	Included with Apple devices	Closed source
Element	Android, iOS, Windows, macOS, Linux, web	Free personal app, paid organization plans	Published, AGPL-3.0
Threema	Android, iOS	Private app is a one-time purchase	Android published, AGPL-3.0

Signal, Telegram and Element have official Linux apps. Messages has no Linux app, and Threema is listed only for Android and iOS.

Published client code lets others read what an app does. Signal and Element publish their client apps under AGPL-3.0. Telegram publishes its client code, with GPL-2.0 for its Android app. Threema publishes its Android code under AGPL-3.0. WhatsApp and Apple's Messages are closed source. Reading code is not an audit, and the rankings do not claim audit results for any of these apps.

Our picks and what to do next

The messaging ranking orders the six apps as follows, with the editorial score in brackets:

1. Signal (92.5): end-to-end encryption on by default for chats and calls, with client apps under AGPL-3.0. Its reach is smaller than WhatsApp's.
2. WhatsApp (90.0): end-to-end encryption for personal chats and the broadest contact reach in the list, with a closed-source client.
3. Telegram (85.0): large groups, public channels and sync across devices, with end-to-end encryption only in Secret Chats.
4. Messages (84.0): built into iPhone, iPad and Mac at no cost, and limited to Apple users in iMessage form.
5. Element (82.0): an encrypted, open, self-hostable app on the Matrix network.
6. Threema (80.5): encryption by default and minimal metadata, with a one-time price for the Private app.

Start with the people you need to reach, because no app is useful if they are not on it. Then choose the encryption default you can rely on, check the sign-up requirements, and test a group call with two people before you move a real group. For the full order and filters, read the messaging apps ranking.