It's really cool how DuckDuckGo can show the packages from Debian/Ubuntu, but for Fedora and RHEL administrators (CentOS too) this isn't very useful, as package names are often different, and in some cases provide a totally different application.
The Fedora Package Database has a JSON API that is easily accessible to determine whether or not a package exists.
For instance a package that does exist returns a bunch of JSON information, and a 200 OK status code.
If you supply a wildcard, chances are you'll get multiple packages returned. The first one is the most relevant.
If a package doesn't exist, we get a JSON error and a 404 status code returned.
Basic Perl example (Perl isn't my forte as you can tell :P)