Good questions. On the front-end I use jsp to enable dynamic page generation and have things like headers and footers included dynamically and also for some variables, like the placeholders for url, have their value dynamically set. The main reason I chose jsp for those use cases was because it works well and is simple to understand even if you have had zero contact with jsp before (maybe if you want to use it more heavily, it is not that simple). For other aspects of the front-end I rely on html, javascript and css.

Regarding the front-end framework, I decided to use only Bootstrap because of simplicity. I avoided (for now) to use something like Angular or React because in my understanding it would increase the complexity of the stack and users, in general, would need more time to understand it, what would cause the side projects/SaaS/MVP they were aiming to build take more time to be released.

Since the product is now available to the public, those decisions may change once I gain more understanding of what customers really want. Thanks for you comment and feel free to leave any additional question/feedback.

Thanks!