Overview

For the complete documentation index, see llms.txt.

Qwen Cloud’s realtime audio API is available in VoxEngine as a native connector. The client streams caller audio to qwen-audio-3.1-realtime-plus and plays the model’s speech back into the call.

Benefits

• Built-in WebSocket connector. VoxEngine opens the Qwen Cloud session and converts call audio, so the scenario keeps call control, routing, and telephony.
• Direct speech-to-speech. One model handles recognition, reasoning, and speech output. The default model is qwen-audio-3.1-realtime-plus.
• Session control from VoxEngine. Send instructions, voice, languages, and turn detection with sessionUpdate after SessionCreated.
• Barge-in. Clear the playback buffer when Qwen reports InputAudioBufferSpeechStarted.
• Function calling. Declare tools in the session, run them in the scenario, and return function_call_output before the next response.

Architecture

VoxEngine sits between the caller and Qwen Cloud. The scenario creates a VoiceAgentAPIClient, applies session.update before the first audio frame, then bridges media.

Tool calls come back as events. The scenario runs the function and sends the result over the same client.

Prerequisites

• A Qwen Cloud API key. The client sends it as Authorization: Bearer.
• Store that key in Voximplant Secrets under QWEN_API_KEY.
• Optional: a Qwen Cloud workspace id, passed as workspace and sent as X-DashScope-WorkSpace.

Development notes

• Load the module with require(Modules.QwenCloud) and create the client with QwenCloud.createVoiceAgentAPIClient.
• model defaults to qwen-audio-3.1-realtime-plus. The examples set it explicitly.
• On SessionCreated, call sessionUpdate before bridging audio. turn_detection can only change before the first audio frame. voice is applied on the first session.update.
• On SessionUpdated, call VoxEngine.sendMediaBetween(call, client).
• Greet the caller by inserting a short user text item with conversationItemCreate, then call responseCreate. The Qwen response.create event accepts response.modalities and response.voice, so the greeting text goes in the conversation item.
• For barge-in, call clearMediaBuffer on InputAudioBufferSpeechStarted.
• The examples use the English system voice beth_v3.1. The model default is longanqian_v3.1. Other 3.1 system voices include betty_v3.1, cally_v3.1, longanhuan_v3.1, longanlingxin_v3.1, longanfengyue_v3.1, and xunanchuan_v3.1. A cloned voice id can be passed in voice.
• Set input_audio_transcription.language and output_audio.language for qwen-audio-3.1-realtime-plus. Output language steers speech. Also say the reply language in instructions if the spoken text must stay in that language.
• turn_detection.type is server_vad by default. Set it to smart_turn for semantic turn detection, or set turn_detection to null for push-to-talk. Push-to-talk then needs inputAudioBufferCommit and responseCreate.
• enable_search and tools cannot be enabled together.
• Function tools use a nested function object. See Function calling.

Examples

• Example: Answering an incoming call
• Example: Placing an outbound call
• Example: Function calling

Links

• Qwen Cloud module API reference
• qwen-audio-3.1-realtime-plus
• Qwen-Audio client events
• Qwen-Audio server events