Signal
Signal lets users send encrypted text messages, make private voice and video calls, and share files with individuals or groups across all major devices at no cost.
Private messaging the way it should be — encrypted by default, free forever, and built by people with no financial interest in your data.
Signal is a free, open-source messaging app developed and maintained by the Signal Foundation, a nonprofit organisation based in the United States. It is built entirely around a single principle: that private communication should be accessible to everyone, without compromise and without cost.
Every message, call, file, and status update sent through Signal is protected by the Signal Protocol, an end-to-end encryption standard so widely trusted that it has been adopted by WhatsApp, Google Messages, and other major platforms. Unlike those platforms, however, Signal is run as a nonprofit with no advertising revenue, no data collection, and no commercial stake in what users say or share.
Signal is available on iOS, Android, Windows, macOS, and Linux, and is used by journalists, government officials, security researchers, and everyday users who want a messaging app they can genuinely trust. It requires a phone number to register, and it is funded entirely through donations.
Apps are frequently updated and may change over time. While we aim to keep our reviews accurate and up to date, some information may become outdated or no longer reflect the current version.
Disclaimer ▽ (click open)
How to Use
Getting started with Signal requires downloading the app from the Apple App Store or Google Play and registering with a phone number. A verification code is sent by SMS, and once confirmed, the app checks whether any existing contacts are already using Signal. No account name or email address is required beyond that.
The main screen displays active conversations. Tapping a contact opens the chat, where text messages, voice notes, photos, videos, GIFs, and files can be sent instantly. All content is encrypted end-to-end by default with no configuration required. Group chats support up to 1,000 members and include admin controls, invite links, and permission settings.
Disappearing messages can be set on any conversation, causing messages to delete automatically after a chosen time period ranging from a few seconds to several weeks. Voice and video calls work directly from the contact view and are fully encrypted, with group calls supported for up to 40 participants.
The desktop app links to the mobile account and syncs message history across devices. A username system, introduced in 2024, allows users to communicate without revealing their phone number to new contacts, adding an additional layer of anonymity for those who need it.
Strongest Points:
✓ End-to-end encryption is applied to every message, call, and file by default — no settings to configure, no opt-in required
✓ Completely free with no subscription, no ads, no in-app purchases, and no commercial data collection of any kind
✓ Open-source codebase that is independently audited and publicly verifiable, with a strong and consistent security track record
✓ Username system allows communication without sharing a phone number, reducing identity exposure when connecting with new contacts
✓ Disappearing messages, note-to-self, encrypted backups, and screen security give users strong day-to-day privacy controls
Weaker Points:
✕ A phone number is required to register, which limits anonymity at the point of account creation despite the username system
✕ Signal's usefulness depends entirely on contacts also using it — adoption friction remains the most common barrier for new users
✕ Feature set is leaner than mainstream messengers — no message scheduling, no advanced media tools, and no channel broadcasting
✕ The desktop app requires a linked mobile device and cannot function fully as a standalone application
✕ Encrypted cloud backup storage beyond the free tier requires a small monthly fee, adding a cost for users with large message histories
How to Use
Getting started with Signal requires downloading the app from the Apple App Store or Google Play and registering with a phone number. A verification code is sent by SMS, and once confirmed, the app checks whether any existing contacts are already using Signal. No account name or email address is required beyond that.
The main screen displays active conversations. Tapping a contact opens the chat, where text messages, voice notes, photos, videos, GIFs, and files can be sent instantly. All content is encrypted end-to-end by default with no configuration required. Group chats support up to 1,000 members and include admin controls, invite links, and permission settings.
Disappearing messages can be set on any conversation, causing messages to delete automatically after a chosen time period ranging from a few seconds to several weeks. Voice and video calls work directly from the contact view and are fully encrypted, with group calls supported for up to 40 participants.
The desktop app links to the mobile account and syncs message history across devices. A username system, introduced in 2024, allows users to communicate without revealing their phone number to new contacts, adding an additional layer of anonymity for those who need it.
Strongest Points:
✓ End-to-end encryption is applied to every message, call, and file by default — no settings to configure, no opt-in required
✓ Completely free with no subscription, no ads, no in-app purchases, and no commercial data collection of any kind
✓ Open-source codebase that is independently audited and publicly verifiable, with a strong and consistent security track record
✓ Username system allows communication without sharing a phone number, reducing identity exposure when connecting with new contacts
✓ Disappearing messages, note-to-self, encrypted backups, and screen security give users strong day-to-day privacy controls
Weaker Points:
✕ A phone number is required to register, which limits anonymity at the point of account creation despite the username system
✕ Signal's usefulness depends entirely on contacts also using it — adoption friction remains the most common barrier for new users
✕ Feature set is leaner than mainstream messengers — no message scheduling, no advanced media tools, and no channel broadcasting
✕ The desktop app requires a linked mobile device and cannot function fully as a standalone application
✕ Encrypted cloud backup storage beyond the free tier requires a small monthly fee, adding a cost for users with large message histories
Use it For:
🔐 Privacy-conscious individuals who want a daily messaging app with no data collection, no ads, and no commercial pressure on their conversations
📰 Journalists, activists, and researchers who require genuinely secure communication for sensitive work or source protection
👥 Friend and family groups who want an encrypted alternative to WhatsApp without giving up group chats, voice calls, or media sharing
💻 Users who communicate across multiple devices and need a consistent, encrypted experience on mobile, desktop, and tablet
🌐 People in countries with restrictive internet environments who need a trustworthy, audited communication tool that cannot be easily compromised
App Usable on:
Phone
Tablet
PC
TV
Applications and Features
Signal covers the full range of personal communication with text messaging, voice calls, video calls, and file sharing, all encrypted using the Signal Protocol end-to-end. Group chats support up to 1,000 members with granular admin controls, including the ability to restrict who can send messages and who can invite new members.
Disappearing messages can be enabled per conversation with timer options ranging from a few seconds to four weeks. Messages can be edited within a short window after sending, and reactions, reply threading, and voice note playback are all supported. The Note to Self feature acts as a private, encrypted space for personal notes, links, and reminders.
Signal introduced a username system in 2024 that allows users to share a username instead of a phone number when connecting with new people. This does not remove the phone number requirement at registration, but it significantly reduces daily identity exposure. Sealed sender technology adds a further layer by hiding metadata about who is sending a message, not just its contents.
Encrypted backups, introduced as a stable feature in 2024, allow message history to be backed up and restored across devices with end-to-end encryption. The free tier covers messages and 45 days of media; expanded storage of 100 GB for all attachments is available for a small monthly fee. IP address protection for calls, safety numbers for contact verification, and a screen lock complete a feature set focused entirely on security without compromise.
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App Summary
Signal holds a position that no other mainstream messaging app can claim: it is entirely free, entirely nonprofit, and built from the ground up to collect as little information about its users as technically possible. The Signal Protocol that powers its encryption is the same standard adopted by WhatsApp and Google, but Signal applies it without any of the data-sharing that comes alongside those platforms.
For everyday users, it functions like any familiar messaging app — quick to set up, easy to navigate, and reliable across devices. The username system and disappearing messages add practical privacy tools that go beyond what most people expect from a free application. Encrypted backups now make device switching straightforward without sacrificing security.
The core limitation is social rather than technical: Signal works best when the people being contacted are also using it. For those who can get their circle across, it is one of the most trustworthy communication tools available at any price.
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Signal is completely free with no subscription, no ads, and no in-app purchases. The only optional cost is expanded encrypted backup storage — 100 GB for all message attachments is available for a small monthly fee, while messages and the last 45 days of media are backed up at no cost. The app is funded entirely through donations.
Learning Difficulty:
Signal uses a clean, familiar chat interface that anyone accustomed to WhatsApp or iMessage will navigate without difficulty, and all encryption works automatically in the background without any configuration from the user.
Required Skill Sets:
Educational Content:
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1/4
Questions & Answers: ⮛ (click to open)
Is Signal really private, or does it still collect data?
Signal collects almost no data by design. The only information stored on its servers is a phone number, the date an account was created, and the date of last connection. Message content, contact lists, group memberships, and call logs are never stored and are not accessible to Signal or anyone else.
Do both people need Signal for messages to be encrypted?
Yes. End-to-end encryption only applies when both the sender and recipient are using Signal. If a message is sent to someone who does not have Signal installed, it will not be delivered through the app at all — Signal does not fall back to unencrypted SMS like some other apps.
Can Signal be used without sharing a phone number with contacts?
Yes. Signal introduced a username system in 2024 that allows users to share a username instead of a phone number when connecting with new contacts. A phone number is still needed to create an account, but it does not need to be visible to the people being contacted.
Is Signal safe to use on a desktop computer?
Yes. Signal offers a desktop app for Windows, macOS, and Linux that syncs with the mobile account and applies the same end-to-end encryption to all messages. The desktop app must be linked to a mobile device to function and cannot be used as a fully standalone account.
Good to Knows: ⮛ (click to open)
• Signal has been reported to be actively used by the CIA for internal day-to-day operations, and it has repeatedly complied with government data requests by having virtually nothing to hand over.
• The app received a major donation of over $100 million from WhatsApp co-founder Brian Acton, which secured its long-term development without the need to commercialise.
• Signal stores only a phone number, random encryption keys, and the date an account was created — even when legally compelled to share data, there is almost nothing available to share.
Takeaways: ⮛ (click to open)
• Signal delivers the strongest combination of privacy, encryption, and usability of any free messaging app — and its nonprofit structure removes any commercial incentive to change that.
• The username system and encrypted backups introduced in 2024 addressed two of the most common complaints, making Signal a more complete daily messaging solution than it has ever been.
• Its main practical challenge remains adoption — getting contacts to install it is the only real barrier to making it a primary messaging app.
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