No instrumentation, no performance tuning!
This is my first time to use grape to build an api service, grape repo has more than 2k watchers, but I'm surprised there is no existing newrelic grape suppport, I just found some gists to do it, and this blog post gave me the idea to add newrelic instrument as grape middleware, but it's not the standard way newrelic recommends.
So I released newrelic-grape gem to help you integrate newrelic into grape.
What you need to do is
require "newrelic-grape" require "rpm_contrib"
and monitor the performance on newrelic.