It may depend on the application itself. If the data requirements are lightweight, you could consider using local storage or web storage, and combine that with say Github Pages. That way the hosting is on Github, but they can choose to fork and host themselves. They can run it locally if they'd like. As long as they have a modern browser with the features you're using it should be good. To go further, making it a PWA would still make use of browser features, but give it the appearance/look and feel of a 'native' application.