Is it necessary to purchase a domain name for ejabberd?

Hello,

I’m new to XMPP, and I’m currently trying to make a connection to ejabberd through the Smack API in Eclipse. However, I keep running into issues, and I realized that an issue might be that I’m trying to host the server on a domain name that might not actually exist. I know this sounds like a stupid question, but is it necessary for me to purchase my own domain name just to try and connect to this ejabberd server? Or is there a way to configure ejabberd to only use localhost, and thus allow my Smack API program to connect to the server?

I’m also open to using Openfire, but I’m not sure if I’d run into the same issues as I am with ejabberd. I don’t know what the benefit of Openfire would be as opposed to ejabberd.

Thank you very much.

is it necessary for me to purchase my own domain name just to try and connect to this ejabberd server?

No

Or is there a way to configure ejabberd to only use localhost, and thus allow my Smack API program to connect to the server?
It has not much to do with ejabberd, or any other XMPP server, running on localhost or not. Smack uses by default SRV RRs to lookup the host for the XMPP domain, if there are none, it will fallback to A RRs. If you have neither, then you need to explicitly specify the host and the port in the connection configuration.

You should choose a domain name / xmpp domain. If you really want to use “localhost” then the JIDs will be “username@localhost” and the roster will contain “friend@localhost” entries.
This short name may cause issues as it contains no “.” and the Smack library may assume that there is a “.” in the domain name (not sure about this). Using “localhost.localdomain” is more save but I still recommend to use a normal domain (e.g. “still-not-registered.com” or “something.local”) and hosts entries for the test client.

Changing the domain name later is a bad idea as it breaks the roster / contacts. So you should also avoid to use the IP address.