Add SimpleX Chat (#1893)

docs/assets/img/messengers/simplex.svg

@@ -0,0 +1,2 @@
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docs/real-time-communication.en.md

@@ -73,6 +73,31 @@ Group voice and video calls are [not](https://github.com/vector-im/element-web/i
 
 The protocol was independently [audited](https://matrix.org/blog/2016/11/21/matrixs-olm-end-to-end-encryption-security-assessment-released-and-implemented-cross-platform-on-riot-at-last) in 2016. The specification for the Matrix protocol can be found in their [documentation](https://spec.matrix.org/latest/). The [Olm](https://matrix.org/docs/projects/other/olm) cryptographic ratchet used by Matrix is an implementation of Signal’s [Double Ratchet algorithm](https://signal.org/docs/specifications/doubleratchet/).
 
+### SimpleX Chat
+
+!!! recommendation
+
+    ![Simplex logo](assets/img/messengers/simplex.svg){ align=right }
+
+    **SimpleX** Chat is an instant messenger that is decentralized and doesn't depend on any unique identifiers such as phone numbers or usernames. Users of SimpleX Chat can scan a QR code or click an invite link to participate in group conversations.
+
+    [:octicons-home-16: Homepage](https://simplex.chat){ .md-button .md-button--primary }
+    [:octicons-eye-16:](https://github.com/simplex-chat/simplex-chat/blob/stable/PRIVACY.md){ .card-link title="Privacy Policy" }
+    [:octicons-info-16:](https://github.com/simplex-chat/simplex-chat/tree/stable/docs){ .card-link title=Documentation}
+    [:octicons-code-16:](https://github.com/simplex-chat){ .card-link title="Source Code" }
+
+    ??? downloads
+
+        - [:simple-googleplay: Google Play](https://play.google.com/store/apps/details?id=chat.simplex.app)
+        - [:simple-appstore: App Store](https://apps.apple.com/us/app/simplex-chat/id1605771084)
+        - [:simple-github: GitHub](https://github.com/simplex-chat/simplex-chat/releases)
+
+SimpleX Chat [was audited](https://simplex.chat/blog/20221108-simplex-chat-v4.2-security-audit-new-website.html) by Trail of Bits in October 2022.
+
+Currently SimpleX Chat only provides a client for Android and iOS. Basic group chatting functionality, direct messaging, editing of messages and markdown are supported. E2EE Audio and Video calls are also supported. 
+
+Your data can be exported, and imported onto another device, as there are no central servers where this is backed up.
+
 ### Session
 
 !!! recommendation