5984
Apache CouchDB document database with HTTP REST API
Apache CouchDB
What is port 5984?
Port 5984 is used by Apache CouchDB, a document-oriented NoSQL database with a built-in HTTP REST API. CouchDB became notorious for a widespread misconfiguration: older versions shipped with anonymous admin access enabled by default, leaving thousands of databases open on the internet. Always enable authentication and bind to localhost or a private network interface.
Quick checks
$
nc -zv example.com 5984
$
nmap -p 5984 example.com
$
telnet example.com 5984