Very close, it uses Electron! Front-end is written in ReactJs. The plot library is react-vis currently, but we're replacing that soon. All the zoom/pan logic we implemented ourselves. Backend is a completely separate process. We've chosen for this architecture as it gives us the flexibility to easily change from desktop product to a web/server product, if we feel like that would be a better fit :) Target users can be very broad and is something we are still figuring out, but at the moment we see that engineers that have to deal with data from tests or simulations are a good fit for Marple.