diff --git a/README.md b/README.md
index 77f2ae09..505f1b9b 100644
--- a/README.md
+++ b/README.md
@@ -160,6 +160,7 @@ Xterm.js is used in several world-class applications to provide great terminal e
 - [**Linode**](https://linode.com): Linode uses xterm.js to provide users a web console for their Linode instances.
 - [**FluffOS**](https://www.fluffos.info): Active maintained LPMUD driver with websocket support.
 - [**x-terminal**](https://atom.io/packages/x-terminal): Atom plugin for providing terminals inside your Atom workspace.
+- [**CoCalc**](https://cocalc.com/): Lots of free software pre-installed, to chat, collaborate, develop, program, publish, research, share, teach, in C++, HTML, Julia, Jupyter, LaTeX, Markdown, Python, R, SageMath, Scala, ...
 
 [And much more...](https://github.com/xtermjs/xterm.js/network/dependents)