Observable - Interactive code examples/posts
Charles Proxy - HTTP proxy / HTTP monitor / Reverse Proxy
nbviewer.org - Rackspace server host Jupyter Notebooks from your github repo
Wireshark - Wireshark is a network protocol analyzer for Unix and Windows. It lets you capture and interactively browse the traffic running on a computer network.
Jupyter - Project Jupyter exists to develop open-source software, open-standards, and services for interactive computing across dozens of programming languages. Ready to get started? Try it in your browser Install the Notebook.
Postman - The Collaboration Platform for API Development