This SCEP server is able to perform very well right out of the box.
However it has one serious flaw. FileDepot isn't very performant.

Doing quick test reveals some serious issues:

Run below command against scep-server (I was running mine in docker)

seq 10 | parallel './scepclient-darwin-arm64 -private-key ./key.key -server-url=http://localhost:9000/scep -challenge=abc' | \grep "badRequest" -c

I ran this test 10 times, and results were varying between 3 and 6 occurrences of badRequest.
I did receive responses very quickly, what is performance in this case, if there is an error rate of ~50%?

error line from server:

ts=2022-02-28T10:25:33.055121419Z caller=service.go:88 msg="failed to sign CSR" err="open depot/scepclient.724.pem: file exists"