But I remember a few months ago I was developing a basic API and testing it through Insomnia. At first, I almost had a heart attack seeing the time it took to answer, between clicking "send" and getting a response back. All this running on localhost, on an old but fairly powerful box (i7-3930k, 64 GB ram). My first reaction was I must have had some sleep() lying around.

Then I looked at the details, and the actual time taken handling the call, etc, as reported by Insomnia was a few ms, all the rest was... I don't know what.

But I do agree than other than that, when interacting with the app itself (switch requests, type, etc) it feels snappy enough. I usually use it alongside IntelliJ, which while fairly fast, isn't terminal-level instantaneous.