We don't have a bundler at all. It's a conscious design decision. After Reason compiles to JS code, no change in your existing pipeline is needed. Passing props down & using local state has scale well for us so far. We also have subscription helpers for some interop cases where the data is external. ReasonReact interops easily with existing ReactJS components. In general, we enable interpolation through not trying to be overbearing or opinionated. I think that router nesting's answer (aka "yes it works since it's _just_ a simple pattern match") is a good way of approaching most "can Reason work with X" questions. It might be a small mindset shift coming from the JS ecosystem where interop between different techs is a bit unclear.