Thank you both (haukex and stevieb) for showing different ways to do it. This is a good example of the benefits of using a module with a proper api. Without the module it needs a url, the decoder, and hash access, all of which could change; while the module neatly hides all the brittle parts behind a simple interface.

#!/usr/bin/perl
# Get the latest version numbers of your favorite modules
# (If they exist and have a normal version number...)
# Usage: $0 Module::Name Other::Module Etc

use strict; use warnings;
use HTTP::Tiny;
use JSON::PP 'decode_json';
use MetaCPAN::Client;

my @ARGS = @ARGV ? @ARGV : ('MetaCPAN::Client','MCE','Plack');

my $http = HTTP::Tiny->new;

for (@ARGS) {
  print "$_\t", decode_json($http->get(
  "http://fastapi.metacpan.org/v1/module/$_"
  )->{content})->{version},"\n"
}

my $cpan = MetaCPAN::Client->new;

for (@ARGS){
    printf "%s: %s\n", $_, $cpan->module($_)->version;
}
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