diff --git a/tools.md b/tools.md
index ff2bc48..f2a4fb8 100644
--- a/tools.md
+++ b/tools.md
@@ -1,21 +1,32 @@
 # Tools for Publishing Computational Content
 
-## Notebooks
+## Notebooks: Run on Server; Interact in Browser
 
 - Jupyter Notebook
 - Colab
 - Deepnote
+- Streamlit.io
 - [Epiphany](https://epiphany.pub/) "a new blogging experience"
-- [Iodide](https://github.com/iodide-project/iodide) Run notebook in the browser
-- [Pyodide](https://github.com/iodide-project/pyodide) Run Python in the browser
 - [Klipse](https://github.com/viebel/klipse) Run interactive code in tech blogs
 - Matlab / R
 - Mathematica
 
-## Programming Environments
+## Notebooks: Run and Interact in Browser
+- - Observable
+- [Iodide](https://github.com/iodide-project/iodide) Run notebook in the browser
+- [Pyodide](https://github.com/iodide-project/pyodide) Run Python in the browser
 
-- Jupyter Lab
-- Streamlit.io
+## Javascript Programming in Browser
+
+- [Playcode](https://playcode.io/) Full-featured Live javascript IDE
+- [Code Sandbox](https://codesandbox.io/) Full-featured Live, colaborative javascript IDE
+- [jsfiddle](https://jsfiddle.net/) Classic javascript snippet site
+- [jsbin](https://jsbin.com/) Another javascript snippet site
+- [Code Pen](https://codepen.io/) Yet another javascript snippet site
+
+## Interesting Full Programming Environments
+
+- [Jupyter Lab](https://jupyterlab.readthedocs.io/en/stable/)
 - Kaggle
 - https://codereef.ai/
 - Light Table http://lighttable.com/
@@ -25,6 +36,7 @@
 
 - [distill.pub](https://distill.pub/)
 - [Papers with Code](https://paperswithcode.com/)
+- [Mathigon]()
 
 ## Debugging Aids