JSON input

As a former Flash developer, I believe your product is great and has huge potential. It would be fantastic to build dynamic content based on data passed in JSON format. In Rive, you could create something like a data contract/interface for named JSON objects, allowing you to control content, events, and so forth based on the supplied values. Externally (e.g., from Flutter), you could pass in a JSON object, and if the format is incorrect, the widget could throw an error indicating an invalid data format.
Currently, in my demo, I have to mix the UI created in Rive with a container (Flutter widgets) for equipment, spells, and so on.
An example usage might be as follows: In one of your tutorials, you present a game UI with screens for Start Game, Save Game, and Load Game, etc. For the Load Game screen, saved games could rely on JSON data (previously retrieved from a server and transformed into an appropriate JSON object).