http://simplytest.me/ has a nifty autocomplete option for the module suggestions. Screenshot attached.
I did a little digging and figured it out that ajax call being made is to the following url.
I could be use the same end point but I need to get the permission and also the data available is not sufficient for my use case. I wanted to know if Drupal.org provides any authentic feeds of modules so that I will be able to list other details, say the download url for the tarball file.