I am trying to test OAuth buttons, but they all (Facebook, Twitter, LinkedIn) come back with errors that seem to signal that I can not test or use them from a local
You can edit the hosts file on windows or linux Windows : C:\Windows\System32\Drivers\etc\hosts Linux : /etc/hosts
localhost name resolution is handled within DNS itself. 127.0.0.1 mywebsite.com
127.0.0.1 mywebsite.com
after you finish your tests you just comment the line you add to disable it