Training Example: Signal – Review the Data, Give Your Score & Compare to the Real AI Evaluation

[H1] Speak Freely
Say "hello" to a different messaging experience. An unexpected focus on privacy, combined with all of the features you expect. Get Signal
[H2] Why use Signal?
Explore below to see why Signal is a simple, powerful, and secure messenger
[H2] Share Without Insecurity
State-of-the-art end-to-end encryption (powered by the open source Signal Protocol) keeps your conversations secure. We can't read your messages or listen to your calls, and no one else can either. Privacy isn’t an optional mode — it’s just the way that Signal works. Every message, every call, every time.
[H3] Say Anything
Share text, voice messages, photos, videos, GIFs and files for free. Signal uses your phone's data connection so you can avoid SMS and MMS fees.
[H3] Speak Freely
Make crystal-clear voice and video calls to people who live across town, or across the ocean, with no long-distance charges.
[H3] Make Privacy Stick
Add a new layer of expression to your conversations with encrypted stickers. You can also create and share your own sticker packs.
[H3] Get Together with Groups
Group chats make it easy to stay connected to your family, friends, and coworkers.
[H2] No ads. No trackers. No kidding.
There are no ads, no affiliate marketers, and no creepy tracking in Signal. So focus on sharing the moments that matter with the people who matter to you.
[H2] Free for Everyone
Signal is an independent nonprofit. We're not tied to any major tech companies, and we can never be acquired by one either. Development is supported by grants and donations from people like you. Donate to Signal

[H1] Donate to Signal
Card, PayPal, Bank Crypto, Stock, DAF Signal is a nonprofit built for you. No ads, no trackers, no surveillance. Donating to Signal helps pay for the servers, bandwidth, and ongoing development to ensure that Signal remains available to the millions of people around the world who count on it to protect their privacy. Thank you for your support! Signal Technology Foundation is a nonprofit under section 501c3 of the US Internal Revenue Code. Tax ID: 82-4506840 Note: You will only receive a badge in your Signal account if you donate inside the Signal app.

[H2] Signal for Mobile
Android iPhone or iPad Or visit signal.org/install from your phone
[H2] Signal for Desktop
Download for Mac To use the Signal desktop app, Signal must first be installed on your phone.
[H3] Not on Mac?
Signal for Windows Signal for Linux - Debian-based distros Download for Windows Download from the Microsoft Store To use the Signal desktop app, Signal must first be installed on your phone.
[H3] Not on Windows?
Signal for Mac Signal for Linux - Debian-based distros Download for Linux To use the Signal desktop app, Signal must first be installed on your phone.
[H3] Not on Linux?
Signal for Mac Signal for Windows

[H3] Label yourself
Nina Berman on 19 Mar 2026
[IMG: A screenshot of a message bubble sent by]
We all take on different roles in relation to our friends, neighbors, family members, and colleagues. Keep those different roles clear in your many Signal group chats by using group member labels, now available in the latest versions of Signal for Android, Desktop, and iOS. Read more...
[H3] Put a pin in it
Nina Berman on 29 Jan 2026
[IMG: A screenshot of a group chat displaying a pinned message at the top of the thread.]
Your most frequently asked questions, dinner reservations, and vacation itineraries are already top of mind. Now they can be top of chat as well.In the latest version of Signal rolling out now, you can pin your most important messages to the top of your 1-1 and group chats. Read more...
[H3] Signal Polls: Yes, no, maybe (yes!)
Nina Berman on 19 Nov 2025
[IMG: A stylized representation of a Signal poll.]
Signal polling: An easier way to see what your group chat really thinks and feels. Read more...
[H3] Signal Protocol and Post-Quantum Ratchets
Graeme Connell and Rolfe Schmidt on 02 Oct 2025
[IMG: A stylized Signal logo inscribed with mathematical symbols representing a qubit.]
We are excited to announce a significant advancement in the security of the Signal Protocol: the introduction of the Sparse Post Quantum Ratchet (SPQR). This new ratchet enhances the Signal Protocol’s resilience against future quantum computing threats while maintaining our existing security guarantees of forward secrecy and post-compromise security. Read more...
[H3] Introducing Signal Secure Backups
jimio on 08 Sep 2025
[IMG: Two Android phones against a light-blue background showing Signal secure backups, allowing the user to opt in to create a secure backup archive of messages and media.]
In the past, if you broke or lost your phone, your Signal message history was gone. This has been a challenge for people whose most important conversations happen on Signal. Think family photos, sweet messages, important documents, or anything else you don’t want to lose forever. This explains why the most common feature request has been backups; a way for people to get Signal messages back even if their phone is lost or damaged.After careful design and development, we are now starting to roll out secure backups, an opt-in feature. This first phase is available in the latest beta release for Android. This will let us further test this feature in a limited setting, before it rolls out to iOS and Desktop in the near future. Read more...
[H3] By Default, Signal Doesn't Recall
jlund on 21 May 2025
[IMG: A screenshot of a Microsoft Windows desktop. Microsoft Paint and Minesweeper are visible behind a black rectangular window that is empty except for graffiti-style text that says]
Signal Desktop now includes support for a new “Screen security” setting that is designed to help prevent your own computer from capturing screenshots of your Signal chats on Windows. This setting is automatically enabled by default in Signal Desktop on Windows 11.If you’re wondering why we’re only implementing this on Windows right now, it’s because the purpose of this setting is to protect your Signal messages from Microsoft Recall. Read more...
[H3] A Synchronized Start for Linked Devices
ravi-signal on 27 Jan 2025
[IMG: A view of a mobile phone displaying the "Finish Linking" step. Two options are displayed: "Transfer Message History" and "Don]
With Signal on Desktop and iPad, you can link your primary Android or iOS account with another device, letting you check and respond to messages in both places or conduct video meetings and calls from the comfort of a bigger screen.Signal’s upcoming beta releases will also introduce the option to transfer your messages and media when you link your primary Signal device to a new Desktop or iPad. Instead of starting fresh, and having only new messages show up, you can choose to bring your chats and your last 45 days of media with you. Or, you can choose not to. Read more...
[H3] Improving Private Signal Calls: Call Links & More
Nina Berman on 11 Nov 2024
[IMG: Desktop view of a Signal video call with five participants against a blue and purple background]
If you love group calls on Signal, but don’t want to create a group chat for every combination of your friends or colleagues, you’re in luck. Today we’re launching call links: Share a link with anyone on Signal and in just a tap or click they can join the call. No group chat required. Read more...
[H3] Proxy Please: Help People Connect to Signal
Meredith Whittaker on 09 Aug 2024Several countries have recently blocked Signal, leaving their residents without a trusted and safe place to communicate.To help in this situation, Signal provides a built-in censorship circumvention feature and also includes support for a simple TLS proxy that can bypass these blocks in many circumstances and let people communicate privately. Read more...
[H3] Keep your phone number private with Signal usernames
Signal on 20 Feb 2024
[IMG: iPhone showing the creation of a Signal username, axolotl.99, on a lightly colored gradient background with floating numbers.]
Signal’s mission and sole focus is private communication. For years, Signal has kept your messages private, your profile information (like your name and profile photo) private, your contacts private, and your groups private – among much else. Now we’re taking that one step further, by making your phone number on Signal more private.Here’s how: Read more...
[H3] Trend report: Use Signal
nina-signal on 13 Dec 2023New long-sleeve shirts and tote bags fresh from the Signal test kitchen:
[IMG: Two longsleeve shirts and a tote bag with stylized neon Signal logo and Cantonese characters reading]
We build Signal for people all over the world. So, of course we wanted to reflect that same global outlook in our merch. Read more...
[H3] Privacy is Priceless, but Signal is Expensive
Meredith Whittaker and Joshua Lund on 16 Nov 2023
[IMG: An illustration of a phone screen displaying the Signal interface. Every interface element is represented by photos of currencies from around the world.]
Signal is the world’s most widely used truly private messaging app, and our cryptographic technologies provide extra layers of privacy beyond the Signal app itself. Since launching in 2013, the Signal Protocol—our end-to-end encryption technology—has become the de facto standard for private communication, protecting the contents of billions of conversations in WhatsApp, Google Messages, and many others. Signal also continues to invest in research and development in the pursuit of extending communications privacy. This commitment underlies our recent work to add a layer of quantum resistance to the Signal Protocol, and our previous work on metadata protection technologies that help keep personal details like your contact list, group membership, profile name, and other intimate information secure. This singular focus on preserving the ability to communicate privately is one reason that we work in the open, documenting our thinking and making our code open source and open to scrutiny—so you don’t have to take our word for it. Read more...
[H3] New Features Roll Call: Fall 2023
nina-signal on 08 Nov 2023
[IMG: A stylized close up checklist with pink checkmarks on a gray background. The truncated text of the checklist reads]
You should be able to communicate without worrying that every gossip tidbit, meme, or joke you share and who you share it with will get churned up into fodder for targeted ads or used to train an AI model. You also shouldn’t have to strip your communications down to the barest and most utilitarian version of relaying information.This is why Signal is dedicated to providing a truly private messaging app, and why we work to constantly make the experience better for everyone who uses it.We want you to know about the improvements we’re making in Signal, even the smaller ones that simply make the app nicer to use. So, starting here we’re publishing a periodic New Features Roll Call, reviewing multiple new features and quality of life improvements in one place. Read more...
[H3] Quantum Resistance and the Signal Protocol
ehrenkret on 19 Sep 2023
[IMG: An abstract illustration of a Bloch Sphere]
The Signal Protocol is a set of cryptographic specifications that provides end-to-end encryption for private communications exchanged daily by billions of people around the world. After its publication in 2013, the Signal Protocol was adopted not only by Signal but well beyond. Technical information on the Signal Protocol can be found in the specifications section of our docs site.Today we are happy to announce the first step in advancing quantum resistance for the Signal Protocol: an upgrade to the X3DH specification which we are calling PQXDH. With this upgrade, we are adding a layer of protection against the threat of a quantum computer being built in the future that is powerful enough to break current encryption standards.This post is written to introduce this work to non-experts, and will review what quantum computing is and the challenges it presents for current cryptographic algorithms, before providing a high level overview of how we are adapting our specifications to answer these challenges. If you would like to skip this summary and explore our PQXDH specification in depth, you can read our technical whitepaper here. Read more...
[H3] Standing firm against threats to private and safe communication
meredith-signal on 09 Mar 2023
[IMG: The Signal logo centered over a map of the UK in the background]
Signal exists to provide people everywhere with a tool for real private communication. That’s our only goal, and we take it very seriously. We’re structured as a nonprofit to ensure that market forces can never put profit or expediency over the safety of those who rely on us. Our work also resonates beyond the Signal app. The Signal Protocol has become the foundation for end-to-end encryption technology that is used and trusted by many private messaging services to protect billions of messages every day.We recognize that privacy is a human right and that free expression and the ability to dissent are fundamental to a safe and vibrant society. But the current state of the Online Safety Bill in the UK puts the future of privacy and expression in grave jeopardy. Read more...
[H3] Signal is for everyone, and everyone is different
nina-signal on 07 Mar 2023
[IMG: An illustration of the earth and the Signal logo]
The tech industry–its products, conceptual frameworks, linguistic conventions, and cultural norms–is largely centered in the US (and, increasingly, China. But we’re focused here on the US, where Signal is based). This is not because the US has better programmers or more visionary entrepreneurs, but due primarily to historical material conditions. For example, early investments in networked computation from the US military, which happened around the same time that the US was becoming a global superpower, which was followed by the privatization and then commercialization of networked computation, then the dot com boom, etc. etc., and here we are. Read more...
[H3] Story Time
nina-signal on 07 Nov 2022
[IMG: Stories on Signal]
If your favorite way to update your friends about life disappears in 24 hours, we’ve got some happy news for you.Stories are now available on Signal for Android and iOS, with Desktop coming soon! Read more...
[H3] Removing SMS support from Signal Android (soon)
nina-signal on 12 Oct 2022For many years, the Signal app on Android has supported sending and receiving plaintext SMS and MMS messages in addition to Signal messages. SMS and MMS are standardized communication protocols that allow mobile devices to send and transmit messages, and most people picking up their phone to text or share memes don’t really think about them.To give some context, when we started supporting SMS, Signal didn’t exist yet. Our Android app was called TextSecure and the Signal encryption protocol was called Axolotl. Almost a decade has passed since then, and a lot has changed. Read more...
[H3] Help people in Iran reconnect to Signal – a request to our community
meredith-signal on 22 Sep 2022Signal is currently blocked in Iran. To help people in the country access Signal, we are republishing and revising a post that we originally posted in February, 2021 during a very similar situation in Iran.If you are willing and able, please follow the instructions below to set up a proxy server that will enable people in Iran to connect to Signal. We are grateful to the community who pitches in to help each other during these moments.If you are currently running a proxy, you will need to make some updates to ensure it continues to function. Update instructions are here. Read more...
[H3] A Message from Signal's New President
meredith-signal on 06 Sep 2022On September 12 I’ll be stepping into the role of Signal’s President, a new position created in collaboration with Signal’s leadership. I am thrilled, and I can’t think of a more meaningful use of my time, or a greater honor. I’ve been a friend, admirer, and champion of Signal since it was RedPhone and TextSecure, and in 2020 I joined Signal’s Board of Directors, helping inform high-level strategy and direction. So in many ways this is a happy step on a long continuum, not a dramatic change.Signal is more important now than ever, and I expect this to stay true well into the future. As President I will dedicate myself to helping Signal build a long taproot so it can grow and thrive in dynamic climates. In this role I will be working with Signal’s CEO and leadership, with a particular focus on guiding Signal’s strategy, ensuring our financial sustainability, sharpening and broadening Signal’s public communications, and whatever else is needed to strengthen the app and the org. Read more...
[H3] Technology Deep Dive: Building a Faster ORAM Layer for Enclaves
gconnell on 19 Aug 2022
[IMG: Header Image]
Private doesn’t mean lonely. Signal’s mission is to help you connect with people in a secure way. This means that you need to know which of your contacts are also on Signal. This is called “contact discovery” and it’s an essential part of any messaging app.Most other communications apps enable contact discovery by maintaining their own internal social graph or by uploading and storing your full address book on their servers. But Signal enables you to find and connect with people in a privacy-preserving way. In short, we let you see which of your friends use Signal, but we don’t want to know who your friends are. Letting you know which of your contacts are using Signal while preserving the privacy of your social map requires some complex engineering choices on our end.In this post, we’ll be diving into some new ways that improve our ability to handle contacts in a privat