Your station speaks the Icecast 2 source protocol, so anything that can broadcast to an Icecast server can broadcast to it: BUTT, Mixxx, RadioDJ, Audio Hijack, SAM, ffmpeg, and most things like them.

This is what you want if you already have a setup — a mixer, a processing chain, a library in RadioDJ — and the browser studio is not where your show lives.

Your Connection Details

On the Go live page, choose Use DJ software instead (a Pro feature). It lists the values below, each with its own Copy button, tells you if the station is off, and shows Connected once your software is on air.

Server — the hostname
Port
Mount — some software calls this the mountpoint or the path
Username — always source
Password — your stream key. Some software calls it the source password or the login.

Copy them from there rather than typing them, and see where these go below for the exact spot in BUTT, Mixxx and ffmpeg.

Where These Go in BUTT, Mixxx and ffmpeg

Each program names the values a little differently. Your values are on the Go live page under Use DJ software instead; the names below are where to paste them.

BUTT

Open Settings → Main → Server → Add.
Set the type to Icecast.
Address: your Server. Port: your Port.
Mountpoint: your Mount, exactly as shown (/my-station). With or without the slash both work: BUTT adds it when it is missing.
User: source. Password: your stream key.

Mixxx

Open Preferences → Live Broadcasting → Server connection.
Set the type to Icecast 2.
Host: your Server, the name only, with no http:// in front. Port: your Port.
Mount: your Mount, with the slash.
Login: source. Password: your stream key.
Then turn on Options → Enable Live Broadcasting to connect.

ffmpeg

Paste this into a terminal, with SERVER, PORT, MOUNT (slash included) and KEY swapped for your values:

ffmpeg -re -i input.mp3 -c:a libmp3lame -b:a 128k -content_type audio/mpeg \
  -f mp3 icecast://source:KEY@SERVER:PORT/MOUNT

Set the Type to Icecast 2

Not Shoutcast. They are different protocols and a Shoutcast client will fail against your station with an error that looks like a wrong password. This is the most common first mistake.

And not OBS: OBS sends RTMP, which is video streaming. It cannot publish to a radio station at all.

Switch the Station On First

Unlike the browser studio, connecting an encoder does not switch your station on. Press Start AutoDJ on the dashboard, then connect; your encoder takes over from AutoDJ the moment it does. An encoder pointed at a station that is off air has nothing to connect to.

Do not leave a long gap between the two, either. A station that is on air with nothing attached and nothing playing takes itself off air after ten minutes, and the symptom is an encoder that connects successfully to a station that has just gone away.

One Source at a Time

A station accepts one broadcaster. While your encoder is connected, the browser studio cannot take over — the dashboard will tell you the station is live from your encoder and will name the software where it can, rather than offering you a studio that could not work.

To swap, disconnect the encoder first. And if you go off air from the dashboard while an encoder is connected, you are asked to confirm, because that cuts off a show running in another application.

Keep Your Key Private

The connection is not encrypted: your software sends the stream key as plain text. Treat it like a password on a shared network, and if you ever paste it somewhere public, make a new one in your station’s settings under Use your own DJ software → New key. A show already on air keeps running; the new key applies the next time your software connects.

If It Will Not Connect

See my encoder will not connect — five causes account for nearly all of it, and one of them is a http:// that should not be there.