Thanks — I’ll help with that. You're asking how to egress an audio track to an RTMP URL. LiveKit does not support sending a single raw Track Egress directly to RTMP. Use the Track Composite Egress (or Room Composite) and set the output to an RTMP stream. This lets LiveKit transcode and push the audio to the RTMP destination. Quick steps 1. Get the

AudioTrackId

for the track you want to egress (from Server API or webhooks). 2. Call the Egress service with a

TrackCompositeEgressRequest

, providing

RoomName

,

AudioTrackId

, and an

Output

set to a

StreamOutput

with

Protocol: RTMP

and the RTMP URL(s). 3. Start the egress; LiveKit will encode and stream the audio to the RTMP endpoint. Example (Go):

info, err := egressClient.StartTrackCompositeEgress(ctx, &livekit.TrackCompositeEgressRequest{
	RoomName:     "my-room",
	AudioTrackId: "audio-track-id",
	Output: &livekit.TrackCompositeEgressRequest_Stream{
		Stream: &livekit.StreamOutput{
			Protocol: livekit.StreamProtocol_RTMP,
			Urls:     []string{"rtmp://live.twitch.tv/app/<stream-key>"},
		},
	},
})

Notes • RTMP output is available only for Track Composite or Room Composite egress—not single Track Egress file exports. • For audio-only streaming, omit

VideoTrackId

. Depending on transcoding, a black/placeholder video stream may be generated for RTMP sinks that require video. If you want, tell me: • Which server SDK you’re using (Go, Node.js, etc.), • The RTMP provider (Twitch, YouTube, custom), and • Whether you need audio-only or audio+placeholder video— and I’ll give the exact request/code sample for your setup. Sources: Universal Egress | LiveKit | server-sdk-js | livekit/livekit_composite | DeepWiki, with interactive elements