Running a local benchmark to compare Node.js and Deno gave me the same magnitude of performance difference. I like the concepts behind Deno but the performance should stay a top priority. Even more for a new technology that is looking for future adoption. If Deno gets faster than Node.js, I adopt it. If it stays 5x less performant than Node.js, I skip it.

Are you running deno 0.10.0 versus Node? Since there has been some internal refactoring it should now be 80% wrt basic http req/sec (ref: https://deno.land/benchmarks.html#all , though the benchmark might have not covered everything)

Overhead from Flatbuffers is a major reason of the slowdown and we are seeking to get rid of it.