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SurveyJS
Open-Source JSON Form Builder to Create Dynamic Forms Right in Your App. With SurveyJS form UI libraries, you can build and style forms in a fully-integrated drag & drop form builder, render them in your JS app, and store form submission data in any backend, inc. PHP, ASP.NET Core, and Node.js.
I'm a huge fan of the scrimba[0] style of teaching. They're a fairly well established startup now, whose content style involves having a screen cast be recorded with an interactive code editor, review window and slides which you can move around and use as an online IDE.
You can interrupt the narrator at any time and interact with their code editor as if it was your own, messing with the code at that time and review the results.
Right now they seem to be focused on fronted skills, namely React and more general web dev topics but I'm very happy with how quickly i was bale to get the hang of React using their courses.
[0] https://scrimba.com/
Love Imba[0] as well which is the programming language Scrimba is written in. Truly revolutionary.
[0] https://imba.io/