Adventure Prompt is an interactive fiction authoring system with a twist. Two or three, even.

As of 2018. most interactive fiction forces a choice. You can have the comfort of CYOA, at the cost of relatively shallow gameplay. Or you can have a proper world model, at the cost of having to use a parser. Which is great if you get it, but has a bunch of downsides:

Adventure Prompt gives you the best of both worlds:

Even better, this happens in an attractive book-like interface that puts everything within easy reach.

Creating adventures also works like in no other authoring system. It's purely declarative for one thing: you only ever set properties on objects, and all objects take the same properties. But it still allows for a variety of behaviors, depending on context. And there's an optional interactive editor where you can do that in much the same way you'd be playing a traditional text adventure.

Last but not least, you can export a finished adventure as a stand-alone web page you can upload anywhere, much like with other popular authoring systems.

Credit where credit is due: Adventure Prompt was originally a clone of Robin Johnson's Versificator 2 engine, though by now the two are quite different.