in reply to How do I tell if my code is using JSON::PP or JSON::XS?

You can:

my $json = JSON->new; print "Using JSON::XS\n" if $json->is_xs();

See the JSON choosing backend documentation and (further down in the documentation) the additional methods section for is_xx and related methods.

Optimising for fewest key strokes only makes sense transmitting to Pluto or beyond