Drive it from a script, a dashboard or a shell
eMule Qt keeps the classic web interface and adds a proper JSON REST API next to it, so the client is something other software can talk to.
REST API
The built-in web server exposes /api/v1/* — connection state and connect/disconnect, search and search results, the download list with pause, resume, cancel and preview per transfer, uploads, shared files, servers, friends, statistics, and preferences over GET and PATCH. Requests are authenticated with an API key, and the server can run over HTTPS.
The web UI and the API are independent switches: you can serve the JSON API without exposing the HTML interface at all, or the other way round. The default port is 4711, and the port-mapping layer will forward it for you if you ask it to.
Command line
A running daemon can be driven straight from the shell, which makes it easy to wire eMule Qt into scripts, file managers and browser handlers:
emulecored --add-link "ed2k://|file|...|/" emulecored --connect emulecored --disconnect emulecored --connect-kad
Why it matters
Build your own dashboard, plot your transfer history, hand ED2K links to the daemon from anywhere on your system, or fold the client into home automation — without screen-scraping a web page that was designed for humans.