install JSON::XS
go to Plugins and enable "External tool"
go to Tools -> Manage External Tools -> add new (the button in the bottom on the left if no icons are shown)
add a name, for example "Format JSON with Perl"
replace the contents of the text area on the right with
#!/usr/bin/env perl use strict; use JSON::XS; local $/ = undef; my $content = <STDIN>; my $j = JSON::XS->new->utf8->pretty(1); my $output = $j->encode($j->decode($content)); print $output;
open your file, then Tools -> External Tools -> "Format JSON with Perl"
you can also set a shortcut in the Manage External Tools window