Reactive programming is a very solid paradigm. It is hard to get it right though. Especially when calculations are asynchronous. Excel is ubiquitous but is universally painful to use for anything beyond quick prototyping.

This was the major motivation for us to create

https://ellx.io

- a platform for visual reactive programming, working in your browser.

ObservableHQ was obviously an inspiration, but we concentrated on making it more production oriented: you can literally build a fully-fledged web application without leaving your browser, around solid reactive abstractions.

Some examples built with Ellx:

[1] https://ellx.io/matyunya/tensorflowjs-simple-demo

[2] https://ellx.io/matyunya/simple-voyager-clone

[3] https://ellx.io/dmaevsky/monte-carlo