That's very interesting. I am guessing ClojureScript generates a lot more code that runs through interfaces that sophisticated JITs can partially evaluate away.

That's very interesting. I am guessing ClojureScript generates a lot more code that runs through interfaces that sophisticated JITs can partially evaluate away. For us, the performance difference was an order of magnitude, to the point that we were too slow in cases for search engines. We were investigating building an external Node proxy instance to prerender pages. I sincerely hope there's no flag or simple tweak we were missing. It's possible the instances were starved for memory, for instance.