• 🖲 Protects your messages and metadata - who you talk to and when.
• 🔐 Double ratchet end-to-end encryption, with additional encryption layer.
• 📱 Mobile apps for Android (Google Play, APK) and iOS.
• 🚀 TestFlight preview for iOS with the new features 1-2 weeks earlier - limited to 10,000 users!
• 🖥 Available as a terminal (console) app / CLI on Linux, MacOS, Windows.

• Why privacy matters
• SimpleX approach to privacy and security
  • Complete privacy
  • Protection against spam and abuse
  • Ownership and security of your data
  • Users own SimpleX network
• Frequently asked questions
• News and updates
• Make a private connection
• Quick installation of a terminal app
• SimpleX Platform design
• For developers
• Roadmap
• Help us pay for 3rd party security audit
• Disclaimer, License

Everyone should care about privacy and security of their communications - innocuous conversations can put you in danger even if there is nothing to hide.

One of the most shocking stories is the experience of Mohamedou Ould Salahi that he wrote about in his memoir and that is shown in The Mauritanian movie. He was put into Guantanamo camp, without trial, and was tortured there for 15 years after a phone call to his relative in Afghanistan, under suspicion of being involved in 9/11 attacks, even though he lived in Germany for the 10 years prior to the attacks.

It is not enough to use an end-to-end encrypted messenger, we all should use the messengers that protect the privacy of our personal networks - who we are connected with.

Unlike any other existing messaging platform, SimpleX has no identifiers assigned to the users - not even random numbers. This protects the privacy of who are you communicating with, hiding it from SimpleX platform servers and from any observers. Read more.

As you have no identifier on SimpleX platform, you cannot be contacted unless you share a one-time invitation link or an optional temporary user address. Read more.

SimpleX stores all user data on client devices, the messages are only held temporarily on SimpleX relay servers until they are received. Read more.

You can use SimpleX with your own servers and still communicate with people using the servers that are pre-configured in the apps or any other SimpleX servers. Read more.

1. How SimpleX can deliver messages without any user identifiers? See v2 release annoucement explaining how SimpleX works.

2. Why should I not just use Signal? This post shows why Signal cannot be considered a private messenger. Signal is a centralised platform that uses phone numbers to identify its users and their contacts.

3. How is it different from Matrix, Session, Ricochet, Cwtch, etc., that also don't require user identites? Although these platforms do not require a real identity, they do rely on anonymous user identities to deliver messages – it can be, for example, an identity key or a random number. Using a persistent user identity, even anonymous, creates a risk that user's connection graph becomes known to the observers and/or service providers, and it can lead to de-anonymizing some users. If the same user profile is used to connect to two different people via any messenger other than SimpleX, these two people can confirm if they are connected to the same person - they would use the same user identifier in the messages. With SimpleX there is no meta-data in common between your conversations with different contacts - the quality that no other messaging platform has.

Selected updates:

Jul 11, 2022. v3.0: instant push notifications for iOS, e2e encrypted WebRTC audio/video calls, chat database export/import, privacy and performance improvements

May 11, 2022. v2.0 released - sending images and files in mobile apps

Mar 08, 2022 Mobile apps for iOS and Android released

Jan 12, 2022. SimpleX v1 released: the only messaging and application platform without user identities

All updates

You need to share a link or scan a QR code (in person or during a video call) to make a connection and start messaging.

The channel through which you share the link does not have to be secure - it is enough that you can confirm who sent you the message and that your SimpleX connection is established.

curl -o- https://raw.githubusercontent.com/simplex-chat/simplex-chat/stable/install.sh | bash

Once the chat client is installed, simply run simplex-chat from your terminal.

Read more about installing and using the terminal app.

SimpleX is a client-server network with a unique network topology that uses redundant, disposable message relay nodes to asynchronously pass messages via unidirectional (simplex) message queues, providing recipient and sender anonymity.

Unlike P2P networks, all messages are passed through one or several server nodes, that do not even need to have persistence. In fact, the current SMP server implementation uses in-memory message storage, persisting only the queue records. SimpleX provides better metadata protection than P2P designs, as no global participant identifiers are used to deliver messages, and avoids the problems of P2P networks.

Unlike federated networks, the server nodes do not have records of the users, do not communicate with each other and do not store messages after they are delivered to the recipients. There is no way to discover the full list of servers participating in SimpleX network. This design avoids the problem of metadata visibility that all federated networks have and better protects from the network-wide attacks.

Only the client devices have information about users, their contacts and groups.

See SimpleX whitepaper for more information on platform objectives and technical design.

We plan that the SimpleX platform will grow into the platform supporting any distributed Internet application. This will allow you to build any service that people can access via chat, with custom web-based UI widgets that anybody with basic HTML/CSS/JavaScript knowledge can create in a few hours.

You already can:

• use SimpleX Chat library to integrate chat functionality into your apps.
• use SimpleX Chat bot templates in Haskell to build your own chat bot services (TypeScript SDK is coming soon).

If you are considering developing with SimpleX platform please get in touch for any advice and support.

• ✅ Easy to deploy SimpleX server with in-memory message storage, without any dependencies.
• ✅ Terminal (console) client with groups and files support.
• ✅ One-click SimpleX server deployment on Linode.
• ✅ End-to-end encryption using double-ratchet protocol with additional encryption layer.
• ✅ Mobile apps v1 for Android and iOS.
• ✅ Private instant notifications for Android using background service.
• ✅ Haskell chat bot templates.
• ✅ v2.0 - supporting images and files in mobile apps.
• ✅ Manual chat history deletion.
• ✅ End-to-end encrypted WebRTC audio and video calls via the mobile apps.
• ✅ Privacy preserving instant notifications for iOS using Apple Push Notification service.
• ✅ Chat database export and import
• 🏗 Chat server and TypeScript client SDK to develop chat interfaces, integrations and chat bots (in progress).
• 🏗 Connecting to messaging servers via Tor (in progress).
• 🏗 Chat groups in mobile apps (in progress).
• Chat database encryption.
• Disappearing messages, with mutual agreement.
• Web widgets for custom interactivity in the chats.
• SMP protocol improvements:
  • SMP queue redundancy and rotation.
  • Message delivery confirmation.
  • Supporting the same profile on multiple devices.
• Privacy-preserving identity server for optional DNS-based contact/group addresses to simplify connection and discovery, but not used to deliver messages:
  • keep all your contacts and groups even if you lose the domain.
  • the server doesn't have information about your contacts and groups.
• Media server to optimize sending large files to groups.
• Channels server for large groups and broadcast channels.

I will get straight to the point: I ask you to support SimpleX Chat with donations.

We are prioritizing users privacy and security - it would be impossible without your support we were lucky to have so far.

We are planning a 3rd party security audit for the app, and it would hugely help us if some part of this $20,000+ expense could be covered with donations.

Our pledge to our users is that SimpleX protocols are and will remain open, and in public domain, - so anybody can build the future implementations of the clients and the servers. We are building SimpleX platform based on the same principles as email and web, but much more private and secure.

If you are already using SimpleX Chat, or plan to use it in the future when it has more features, please consider making a donation - it will help us to raise more funds. Donating any amount, even the price of the cup of coffee, would make a huge difference for us.

It is possible to donate via GitHub, which is commission-free for us, or via OpenCollective, that also accepts donations in crypto-currencies, but charges a commission.

Thank you,

Evgeny

SimpleX Chat founder

SimpleX protocols and security model was reviewed and had many improvements in v1.0.0; we are currently arranging for the independent implementation audit.

You are likely to discover some bugs - we would really appreciate if you use it and let us know anything that needs to be fixed or improved.

AGPL v3