10 second video of Livecoding a WhatsApp webhook in an @observablehq notebook. Note the cells are updating in realtime as the notebook responds to live WhatsApp events. Data is plotted and serialized and send back as images on-demand. Code changes are instantaneous. This is the developer experience I have been working towards and I am praying it is beginning to be understandable from video.

Can you change code, see the interface change in real time, then do something in the interface and see the notebook change? That would be very persuasive to me.

If I understand the demo, the notebook is basically watching/scraping the WhatsApp web app, I don't think it can control that UI

@Jason Morris yes, in a different context (I can't control whatsApp UI) you can leverage Observables hot code reload to keep state in one or more cells, yet change the rendering UI code in another cell, so the UI updates but the state is not. My contribution is extending this ergonomic hot code reload that Observable already provides to serverless programming. @Chris Knott yeah, specifically its using Twilio's WhatsApp webhook integration, full gory details is https://observablehq.com/@tomlarkworthy/dashboards-over-whatsapp