So, what's the big idea?

Perl projects have all manner of ways of declaring their dependencies. CPAN releases usually include a file called META.yml or META.json listing their dependencies (though Makefile.PL or Build.PL is also supposed to generate a list of dependencies when it runs; this allows the release to dynamically decide on different dependencies based on the machine it's running on). Non-CPAN projects can declare their CPAN dependencies using cpanfile too.

Once the dependencies are declared, this information is used by CPAN clients, by metacpan.org (to show the list of a release's dependencies), by http://deps.cpantesters.org/ and so on.

However, this only works where you want to declare dependencies on CPAN modules, or on a minimum version of Perl itself.

OK, so sometimes you decide you're going to stop using some module X, maybe because something better has come along. Let's say I want to track down all my CPAN modules that use Any::Moose because my goal is to port each of them to either Moose or Moo.

MetaCPAN has all the dependency information, but I don't want to click through each of my distributions. Enter the MetaCPAN API...