Secure Messaging Apps: A Comparison

In a world full of technology, there is plenty of information to be found online. Unfortunately, there are also a lot of people who take advantage of this information. If your personal information isn’t stored securely, it can be easily accessed by ill-intending individuals or groups.

This raises an obvious question: what actually makes for secure information storage in a messaging app? Popularity alone doesn’t answer that question, and marketing claims about “military-grade encryption” don’t always hold up under closer inspection either. Today, we’re going to look at five different messaging apps and their actual security practices, then compare them to figure out which ones genuinely deserve your trust. For broader account security tips beyond just messaging apps, see our guide on securing your online presence.

Telegram

Telegram was developed in 2013 and was one of the first mainstream apps to offer end-to-end encryption at all. End-to-end encryption means the messages sent and stored between two people are encrypted in a way that a third party can’t decrypt, keeping the conversation genuinely private between the two of you. However, Telegram doesn’t apply end-to-end encryption to group chats by default, and those groups can contain up to 200,000 members, meaning most Telegram conversations aren’t as locked down as people assume.

What Telegram does offer is self-destructing messages through its “Secret Chats” feature. These messages delete themselves after a set amount of time, which helps limit how long sensitive information sticks around and who might be able to see it over your shoulder.

The catch is that this stronger end-to-end encryption is optional rather than the default. Regular Telegram chats use standard encryption in transit, but not the device-to-device encryption that Secret Chats provide, and it’s widely assumed that most users never actually switch over to using Secret Chats for their day-to-day conversations.

Another downside worth knowing is that Telegram’s exact corporate structure and headquarters have shifted around over the years, which has made it historically difficult to pin down which country’s legal jurisdiction actually applies to the company. Telegram also relies on its own custom encryption protocol (MTProto) rather than a widely peer-reviewed standard, which makes it harder for independent security researchers to fully audit.

Signal

Signal is developed by the Signal Foundation, a nonprofit funded through donations and grants rather than advertising or data sales. All of its software is free, open-source, and publicly auditable, which is a meaningfully different trust model than most other apps on this list.

Signal covers the same basics as any other messaging app — text, images, videos, music, and files sent to your contacts. Like Telegram, it supports self-destructing messages, with a timer you can set anywhere from five seconds up to a full week.

On top of that, Signal also offers screenshot-blocking for certain sensitive content, helping prevent information from being easily saved by someone you’ve shared it with.

Crucially, Signal uses end-to-end encryption by default for every single conversation, group chats included, without requiring users to opt in or configure anything themselves. When you add a new contact, you have the option to take an extra step and verify their identity through safety numbers or a QR code, protecting against more sophisticated interception attempts. Signal also refuses to back up your conversation history to the cloud, storing everything locally on your device instead.

The main downside of Signal is that it requires a working phone number with SMS access to verify your account, which means people without an active SIM card can’t easily sign up.

WhatsApp

WhatsApp is possibly the most popular messaging app in the world, with well over two billion people using it. Given that scale, it’s tempting to assume it must be safe simply because so many people already trust it. Let’s actually look at WhatsApp’s security measures to see whether that assumption holds up.

Since 2016, all WhatsApp messages have been protected by end-to-end encryption built on the Signal protocol, the same underlying technology that powers Signal itself. This prevents any third party, including WhatsApp as a company, from reading the actual content of messages sent between users.

Each contact you talk to has a unique security code you can use to verify their identity, though this verification step is manual and most users never bother to check it. When properly used, this encryption protects conversations from being intercepted or read by a middleman, even one with access to WhatsApp’s own servers.

That said, when WhatsApp was acquired by Facebook (now Meta) back in 2014, a later terms-of-service update raised real concerns by proposing to share WhatsApp account data with Facebook for things like targeted advertising. WhatsApp eventually paused that specific sharing in some regions following regulatory pushback, but the episode understandably left a lot of users uneasy about the platform’s long-term data practices.

Another meaningful downside: when conversations are backed up to the cloud (to Google Drive or iCloud, depending on your device), that backup typically isn’t covered by the same end-to-end encryption protecting the live conversation, which means a compromised cloud account could still expose your chat history to a third party.

WhatsApp does have one genuinely useful perk, though: the ability to delete messages after they’ve already been sent. This is limited to roughly an hour after sending, but it can prevent the recipient from seeing something you sent by mistake. It can be deleted for just yourself or for both parties, though a “this message was deleted” notice stays behind either way.

Threema

Threema is a Switzerland-based app with several million users. While it’s most popular in German-speaking countries, it offers a feature not many other apps have: a clean way to separate business and personal conversations within the same account.

When you register, you receive an anonymous ID and password rather than needing to hand over a phone number or email. You’re not required to fill in a profile name or picture either, and linking the account to your email or phone number is entirely optional, which makes it one of the more genuinely private apps on this list by design.

The app can access your contacts to help you find people you already know, but this can be easily switched off to preserve your privacy further. Threema refers to this philosophy as “data restraint” — the idea being that data the company never collects in the first place can’t later be leaked, subpoenaed, or misused.

You can lock private chats behind a PIN code for an extra layer of protection when you hand your phone to someone else. Each contact is also color-coded by trust level: green for people you’ve verified in person, yellow for people verified through some other method, and red for unverified contacts. Marking someone as “green” requires physically scanning their QR code together, which is a small bit of friction that meaningfully raises the bar for impersonation.

The main current downside is that Threema doesn’t yet offer video calling. Its security model otherwise holds up well under scrutiny, with no major faults uncovered so far. The app also costs a small one-time fee, typically a few dollars depending on your app store and region.

What actually matters when choosing a secure app

Across all four of these apps, a few themes keep coming up that are worth paying attention to regardless of which one you pick: whether encryption is on by default or something you have to remember to enable, whether cloud backups quietly undermine that encryption, whether the company can see your metadata even if it can’t read your messages, and how much personal information you’re required to hand over just to create an account in the first place. A single flashy feature, like self-destructing messages, matters a lot less than these underlying defaults.

iMessage

Apple’s iMessage is worth a mention too, since it’s the default for hundreds of millions of iPhone users who may never have consciously chosen it as their “secure” messaging app. iMessage does use end-to-end encryption by default for messages sent between Apple devices, which puts it ahead of apps where encryption is opt-in. The catch is that iMessage automatically falls back to unencrypted SMS when messaging an Android device, and iCloud backups of your messages have historically been accessible to Apple under certain legal circumstances, unless you specifically enable Advanced Data Protection.

For Apple-only friend and family groups who want reasonable security without downloading anything new, iMessage is a solid baseline. For anything more sensitive, or for conversations that cross over to Android users, it’s worth pairing it with one of the dedicated apps above instead.

How to actually make the switch

If you’ve decided to move away from a less secure app, the hardest part is usually just getting the people you talk to most to switch with you. If you’re still deciding which app to move to based on features rather than just security, our comparison of popular messaging apps covers that angle too. Start with your closest circle rather than trying to convert everyone at once — a partner, a couple of close friends, or a family group chat. Once a small group is comfortable with the new app, it tends to spread naturally as people see it working. It also helps to keep your old app installed during the transition, so you don’t miss anything important while everyone gradually catches up.

Conclusion

Right now, we’ve compared five well-known messaging apps based on their features and, more importantly, their actual security practices. As always, the final decision is yours to make. That said, when it comes to Telegram and WhatsApp specifically, we’d encourage some caution — Telegram’s default encryption gaps and WhatsApp’s corporate ownership history are both worth weighing carefully before trusting either with genuinely sensitive conversations.

Signal is a trustworthy, well-audited alternative to WhatsApp that’s worth switching to if privacy is a real priority for you. You will need access to a phone with a working SIM card to activate an account, though, which is worth knowing upfront.

We’d also genuinely recommend Threema, even though it’s less well known than Signal. The app is secure, can be set up without handing over your email or phone number, and lets you manually verify people you actually trust. You do need to pay a small one-time fee for it, but that cost is minor compared to the value of not handing your personal information over to an unknown third party.