Updated 16 October 2026 · Edited by the Benchmark Buyer team · How we review
We do the homework you'd do before buying, so you don't have to. Like any careful buyer, we read the independent security research, each app's own privacy policy and the expert reviews, then sum up where they agree and where they don't. We don't run our own tests. There are no standard lab tests for messaging apps, so this guide draws on what each app says it encrypts and keeps, 4 independent security analyses published since May 2025, and 5 expert reviews published between July 2025 and September 2026.
The short answer
Signal is the clearest consensus pick. All five expert sources we counted include it, all of them in their top three, and it is the only ranked app with a recent independent analysis whose problems were fixed. Threema is a close second if you'd rather not give a phone number. SimpleX Chat goes furthest on collecting nothing about you, but few experts cover it yet.
Not end-to-end encrypted unless you start a secret chat
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Big groups and channels, not privacy
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Stars show the consensus score out of 10, turned into a 5-star scale and rounded to the nearest half star; the exact score is in each product's section. Security evidence sums up whether chats are end-to-end encrypted by default, whether the code is published, how much data the app's own privacy policy says it keeps, and any independent security analysis from the last 18 months. Popularity (●●●● very high to ●○○○ lower) is based on how many people have rated each app on Google Play: very high (5m+ ratings), high (1m+), medium (500k+) or lower. It shows how widely used an app is, not how good it is, so it doesn't affect the score.
1. Signal: the app every expert includes
★★★★★Consensus score: 9.6
Signal is the only app on all five expert lists. Zapier, Privacy Guides and CloudSEK put it first, TechRadar second and eSecurity Planet third. Every chat and call is end-to-end encrypted by default, and Signal says it "cannot decrypt or otherwise access the content of your messages or calls". Its apps and its server code are published on GitHub. In April 2026 an independent formal analysis of the Double Ratchet, the method Signal uses to keep changing its encryption keys, proved its main security properties. It also found three weaknesses in forward secrecy, two of them in Signal's own code, and all three were reported and fixed.
"Signal is the benchmark secure text messaging app" (Zapier)
"Contact lists on Signal are encrypted using your Signal PIN and the server does not have access to them." (Privacy Guides)
Where opinions differ: you need a phone number to sign up, which is the one piece of data we count against it. Zapier names that link to a phone number among Signal's drawbacks. In 2026 a run of phishing attacks that took over Signal accounts led the President of Germany's Bundestag to advise MPs to use Wire instead. Signal said its infrastructure and encryption were not compromised (CyberInsider).
Who it suits: almost anyone who wants private chats and calls and can get their contacts to install it.
2. Threema: private messaging without a phone number
★★★★½Consensus score: 8.9
Four of the five expert lists include Threema. Zapier ranks it second and calls it the best secure messaging app you pay for, CloudSEK puts it third for metadata protection, and TechRadar and eSecurity Planet both place it fourth. Its privacy policy says a phone number and email address are optional, contact syncing is off unless you turn it on, and hashed contact details are deleted from its servers after each sync. Its apps' source code is public; Threema's security page doesn't mention its server code.
"Threema is a Swiss-made secure messaging app specializing in absolute privacy and anonymity." (eSecurity Planet)
"The app can be used anonymously, and it's not just messages but also phone calls that can be securely encrypted." (TechRadar)
Threema's most recent published audits (Cure53 in 2024, a university analysis in 2023) are older than our 18-month limit. That isn't counted against it; its security score is based on what we could check.
Who it suits: people who don't want their messaging account tied to a phone number and are happy to pay for the app.
Privacy Guides recommends SimpleX Chat alongside Signal, and CloudSEK names it best for messaging without an ID. Its privacy policy says its servers "do not create, store or identify user chat profiles", messages are removed from its relay servers once delivered (or after 21 days), and the servers can't read even the size of your messages. The apps and the server code are published.
"SimpleX Chat is an instant messenger that doesn't depend on any unique identifiers such as phone numbers or usernames." (Privacy Guides)
Where opinions differ: only two of the five expert sources list it, and CloudSEK puts it last of eight. Its last independent review (Trail of Bits, October 2024) is older than our 18-month limit, so its top security score rests on what it publishes about itself.
Who it suits: people who want to share as little about themselves as possible and don't mind adding contacts by QR code or invite link.
eSecurity Planet names Wire best for secure enterprise collaboration and CloudSEK best for business communication. Chats are end-to-end encrypted and Wire says it doesn't have access to the keys. Its apps and server code are published. But its own privacy policy lists more data than the apps above: an email address to sign up, technical logs kept for up to 90 days, your registration IP address, and usage data kept for up to a year.
"Wire works most naturally in structured company environments where internal account management matters." (CloudSEK)
A government edition, Wire Bund, is approved by Germany's federal cyber security agency (BSI) for classified information (CyberInsider). We found no independent audit of Wire's consumer app from the last 18 months.
Who it suits: organisations that want encrypted team chat with central account management.
5. WhatsApp: strong encryption, but more data and closed code
★★★½☆Consensus score: 6.7
TechRadar ranks WhatsApp first and Zapier third, both mainly because so many people already use it. Messages and calls are end-to-end encrypted by default, using the encryption protocol developed by Signal. A May 2025 formal analysis by researchers at King's College London and Royal Holloway proved the security guarantees of WhatsApp's multi-device group chats and set out their limits. WhatsApp doesn't publish its code, and its privacy policy says it needs your phone number and collects usage, device and connection information, plus your address book if you choose to sync it.
"WhatsApp is also wildly popular, so there's a good chance your contacts are already using it." (Zapier)
Where opinions differ: TechRadar's top pick, but Privacy Guides and CloudSEK leave it out. In November 2025 University of Vienna researchers showed they could use WhatsApp's contact lookup to check about 3.5 billion accounts, collecting phone numbers and, where set to public, profile photos and "about" text. Meta said no messages were exposed and added protections from September 2025 (Security Affairs).
Who it suits: people who need to reach friends and family who won't switch apps.
TechRadar ranks Telegram third and CloudSEK second, for performance and for large groups and channels. But Telegram's own privacy policy says normal "cloud chats" are stored on its servers; only secret chats, which you have to start yourself, are end-to-end encrypted. It may keep your IP address and device details for up to 12 months. Its apps are open source; Telegram's source code page doesn't cover its servers. A May 2026 review by Symbolic Software found that a fixed identifier in Telegram's traffic lets someone watching the network track a user across restarts, IP changes, VPNs and Tor.
"Telegram is almost as well-respected as Signal is, although its encryption methods aren't open source" (TechRadar)
Where opinions differ: the two experts who list it rank it highly for features, but it scores lowest here on security evidence.
Who it suits: following channels and running large public groups. For private conversations, the apps above are stronger.
Apple's iMessage isn't ranked because none of our five fresh expert sources includes it.
Not ranked, and why
Session is on only one of our five expert lists (CloudSEK, best for anonymous messaging). A June 2026 paper from the University of Osaka showed impersonation, timestamp-forgery and message-replay attacks on its protocol (IACR ePrint 2026/1247).
Briar, Element, AWS Wickr and Facebook Messenger each appear on only one expert list. We need at least two to rank an app.
Molly is an alternative Android app for Signal accounts, recommended by Privacy Guides alongside Signal, so it is covered by Signal's entry.
How we score
We don't run our own tests. Each app's consensus score combines three things:
Security evidence (50%): up to four checks, each scored out of 100 and averaged.
End-to-end encryption by default for all chats: 100 if yes, 0 if not.
Published code: 100 if the apps and server code are public, 70 if only the apps, 0 if neither.
Data kept: starting from 100, minus 20 for each of the following that the app's own privacy policy says it requires or keeps: a phone number or email address, your contacts, IP addresses or logs, usage analytics, or messages it can read.
Independent security analysis from the last 18 months: 90 if problems were found and fixed, 80 if security was proved with stated limits, 40 if a weakness was left unfixed. Work commissioned by or written with the app maker is mentioned but not scored. If there is no recent analysis, this check is left out rather than scored as zero.
Expert rankings (35%): each app's position in 5 expert lists, from TechRadar, Zapier, eSecurity Planet, Privacy Guides and CloudSEK.
Breadth of agreement (15%): how many of those 5 lists include the app.
To be ranked, an app needs a place in at least two expert lists. No app can score above 9.9. We leave out evidence older than 18 months; for example, Tom's Guide's list was last updated in March 2025, so it isn't counted. Affiliate commission plays no part in the score.
Evidence last checked: 16 October 2026. Full details on how we review.