I'm curious how one would leverage the destination...
# ask-aie
echoing-glass-72062
04/16/2026, 6:46 PMI'm curious how one would leverage the destinationSID/Identities to implement a direct send feature.
✅ 1
t
tall-airline-16756
04/16/2026, 6:46 PMThanks for reaching out, Josh. I'm an AI assistant and I'm here to help. Give me a moment while I research this topic.
tall-airline-16756
04/16/2026, 6:47 PMThanks — I’ll explain how to use destination identities/SIDs to build a direct-send feature and what to consider.
What I’m answering: how to target a specific participant (direct send) using destination identities/SIDs.
Short summary
• Use participant identities (user-defined strings) to target specific recipients — they’re predictable and easier to use than SIDs.
• Send data via the local participant’s data publish methods (or RPC for request/response), specifying destinationIdentities (or destinationIdentity) and a topic.
• Choose RELIABLE vs LOSSY based on whether delivery guarantees matter.
• Use topics to distinguish message types (e.g., "private-chat", "file-transfer").
• Handle unreachable/disconnected targets and timeouts for RPC calls.
Basic patterns (across SDKs)
• Direct data send (broadcast to specific identities)
a. Create the payload (JSON or bytes).
b. Call publishData / publish_data with destinationIdentities: [ "user-123" ] and topic.
c. The recipient checks topic in the Room DataReceived event and processes the message.
• RPC (request–response to one participant)
a. Caller: performRpc(destinationIdentity="user-123", method="name", payload, responseTimeout=…).
b. Callee: implement RPC handler to respond.
Example snippets (conceptual)
• JS/TS: room.localParticipant.publishData(payloadBytes, DataPacket_Kind.RELIABLE, { destinationIdentities: ["user-123"], topic: "private-message" })
• Python: await local_participant.publish_data(payload="hi", reliable=True, destination_identities=["user-123"], topic="private-message")
• Kotlin: room.localParticipant.publishData(dataBytes, DataPublishReliability.RELIABLE, identities=listOf(Identity("user-123")))
Implementation suggestions
• Use identities for targeting; reserve SIDs only when you need server-generated identifiers.
• Use topics to route messages and avoid collision with global broadcasts.
• For large payloads (files), implement chunking or a separate file-transfer topic/stream.
• On the receiver, verify sender identity and topic before processing.
• Add retries/timeouts and user-online checks for reliability; use RPC when you need a response.
If you’d like, tell me:
• Which SDK (JS/Python/Android/Flutter) you’re using and whether you need one-way messages, request-response, or file transfer — I’ll provide a focused code example and error-handling template. Sources: client-sdk-js | livekit/livekit_composite | DeepWiki | livekit-api/livekit/api/room_service.py | livekit-android-sdk/src/main/java/io/livekit/android/room/participant/Local... | lib/src/participant/local.dart | Images | LiveKit Documentation, with interactive elements
e
echoing-glass-72062
04/16/2026, 6:55 PMWe're using Go for a server-side bridge
t
tall-airline-16756
04/16/2026, 6:56 PMThanks — I’ll show how to implement direct send from a Go server-side bridge and what to watch for.
What I’m answering: sending data or RPCs from your Go bridge to specific participants using destination identities/SIDs.
Quick summary
• Prefer targeting participant identities (predictable) over SIDs.
• Use data publish for one-way direct messages and PerformRpc for request/response.
• Specify destination identities, topic, and reliability when publishing.
• Handle disconnected targets, timeouts, payload limits (RPC ≤ 15 KiB), and chunking for large payloads.
Go examples
1) Direct one-way data send (reliable, topic, target identities)
Copy code
payload := []byte("hello user-123")
err := localParticipant.PublishDataPacket(
payload,
WithDataPublishDestination([]string{"user-123"}),
WithDataPublishReliable(true),
WithDataPublishTopic("private-message"),
)
if err != nil { /* handle error */ } Copy code
res, err := localParticipant.PerformRpc(PerformRpcParams{
DestinationIdentity: "user-123",
Method: "privateMessage",
Payload: "ping",
ResponseTimeout: &timeout, // e.g., time.Duration(5)*time.Second
})
if err != nil {
// check error type: RpcRecipientDisconnected, RpcResponseTimeout, RpcRequestPayloadTooLarge, etc.
}
if res != nil { fmt.Println("response:", *res) }2 Views