
Build real-time voice AI applications using Azure AI Voice Live SDK (azure-ai-voicelive). Use this skill when creating Python applications that need real-time…
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by microsoft
Build real-time voice AI applications using Azure AI Voice Live SDK (azure-ai-voicelive). Use this skill when creating Python applications that need real-time…
npx skills add https://github.com/microsoft/agent-skills --skill azure-ai-voicelive-py
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Azure AI Voice Live SDK
Build real-time voice AI applications with bidirectional WebSocket communication.
Environment Variables
AZURE_COGNITIVE_SERVICES_ENDPOINT=https:// .api.cognitive.microsoft.com # Required for all auth methods
AZURE_TOKEN_CREDENTIALS=prod # Required only if DefaultAzureCredential is used in production
AZURE_COGNITIVE_SERVICES_KEY= # Only required for the legacy API-key auth path below
Authentication & Lifecycle
🔑 Two rules apply to every code sample below:
-
Prefer
DefaultAzureCredential. It works locally (Azure CLI / VS Code / Developer CLI) and in Azure (managed identity, workload identity) with no code change. Avoid connection strings, account/API keys — they bypass Entra audit and rotation. -
Local dev:
DefaultAzureCredentialworks as-is. -
Production: set
AZURE_TOKEN_CREDENTIALS=prod(orAZURE_TOKEN_CREDENTIALS=<specific_credential>) to constrain the credential chain to production-safe credentials. -
Wrap every client in a context manager so HTTP transports, sockets, and token caches are released deterministically:
-
Sync:
with <Client>(...) as client: -
Async:
async with <Client>(...) as client:andasync with DefaultAzureCredential() as credential:(fromazure.identity.aio)
Snippets may abbreviate this setup, but production code should always follow both rules.
import os
from azure.ai.voicelive.aio import connect
from azure.identity.aio import DefaultAzureCredential, ManagedIdentityCredential
# Local dev: DefaultAzureCredential. Production: set AZURE_TOKEN_CREDENTIALS=prod or AZURE_TOKEN_CREDENTIALS=
# Or use a specific credential directly in production:
# See https://learn.microsoft.com/python/api/overview/azure/identity-readme?view=azure-python#credential-classes
# credential = ManagedIdentityCredential()
async with DefaultAzureCredential(require_envvar=True) as credential:
async with connect(
endpoint=os.environ["AZURE_COGNITIVE_SERVICES_ENDPOINT"],
credential=credential,
model="gpt-4o-realtime-preview",
credential_scopes=["https://cognitiveservices.azure.com/.default"]
) as conn:
...
Legacy: API Key (existing keyed deployments)
New code should use DefaultAzureCredential above. Use AzureKeyCredential only if you have an existing keyed deployment that hasn't been migrated to Entra ID yet — for example, regulated environments still completing their Entra rollout.
import os
from azure.core.credentials import AzureKeyCredential
from azure.ai.voicelive.aio import connect
async with connect(
endpoint=os.environ["AZURE_COGNITIVE_SERVICES_ENDPOINT"],
credential=AzureKeyCredential(os.environ["AZURE_COGNITIVE_SERVICES_KEY"]),
model="gpt-4o-realtime-preview",
) as conn:
...
Core Architecture
Connection Resources
The VoiceLiveConnection exposes these resources:
Resource Purpose Key Methods
conn.session Session configuration update(session=...)
conn.response Model responses create(), cancel()
conn.input_audio_buffer Audio input append(), commit(), clear()
conn.output_audio_buffer Audio output clear()
conn.conversation Conversation state item.create(), item.delete(), item.truncate()
conn.transcription_session Transcription config update(session=...)
Audio Streaming
Send Audio (Base64 PCM16)
import base64
# Read audio chunk (16-bit PCM, 24kHz mono)
audio_chunk = await read_audio_from_microphone()
b64_audio = base64.b64encode(audio_chunk).decode()
await conn.input_audio_buffer.append(audio=b64_audio)
Receive Audio
async for event in conn:
if event.type == "response.audio.delta":
audio_bytes = base64.b64decode(event.delta)
await play_audio(audio_bytes)
elif event.type == "response.audio.done":
print("Audio complete")
Event Handling
async for event in conn:
match event.type:
# Session events
case "session.created":
print(f"Session: {event.session}")
case "session.updated":
print("Session updated")
# Audio input events
case "input_audio_buffer.speech_started":
print(f"Speech started at {event.audio_start_ms}ms")
case "input_audio_buffer.speech_stopped":
print(f"Speech stopped at {event.audio_end_ms}ms")
# Transcription events
case "conversation.item.input_audio_transcription.completed":
print(f"User said: {event.transcript}")
case "conversation.item.input_audio_transcription.delta":
print(f"Partial: {event.delta}")
# Response events
case "response.created":
print(f"Response started: {event.response.id}")
case "response.audio_transcript.delta":
print(event.delta, end="", flush=True)
case "response.audio.delta":
audio = base64.b64decode(event.delta)
case "response.done":
print(f"Response complete: {event.response.status}")
# Function calls
case "response.function_call_arguments.done":
result = handle_function(event.name, event.arguments)
await conn.conversation.item.create(item={
"type": "function_call_output",
"call_id": event.call_id,
"output": json.dumps(result)
})
await conn.response.create()
# Errors
case "error":
print(f"Error: {event.error.message}")
Common Patterns
Manual Turn Mode (No VAD)
await conn.session.update(session={"turn_detection": None})
# Manually control turns
await conn.input_audio_buffer.append(audio=b64_audio)
await conn.input_audio_buffer.commit() # End of user turn
await conn.response.create() # Trigger response
Interrupt Handling
async for event in conn:
if event.type == "input_audio_buffer.speech_started":
# User interrupted - cancel current response
await conn.response.cancel()
await conn.output_audio_buffer.clear()
Conversation History
# Add system message
await conn.conversation.item.create(item={
"type": "message",
"role": "system",
"content": [{"type": "input_text", "text": "Be concise."}]
})
# Add user message
await conn.conversation.item.create(item={
"type": "message",
"role": "user",
"content": [{"type": "input_text", "text": "Hello!"}]
})
await conn.response.create()
Voice Options
Voice Description
alloy Neutral, balanced
echo Warm, conversational
shimmer Clear, professional
sage Calm, authoritative
coral Friendly, upbeat
ash Deep, measured
ballad Expressive
verse Storytelling
Azure voices: Use AzureStandardVoice, AzureCustomVoice, or AzurePersonalVoice models.
Audio Formats
Format Sample Rate Use Case
pcm16 24kHz Default, high quality
pcm16-8000hz 8kHz Telephony
pcm16-16000hz 16kHz Voice assistants
g711_ulaw 8kHz Telephony (US)
g711_alaw 8kHz Telephony (EU)
Turn Detection Options
# Server VAD (default)
{"type": "server_vad", "threshold": 0.5, "silence_duration_ms": 500}
# Azure Semantic VAD (smarter detection)
{"type": "azure_semantic_vad"}
{"type": "azure_semantic_vad_en"} # English optimized
{"type": "azure_semantic_vad_multilingual"}
Error Handling
from azure.ai.voicelive.aio import ConnectionError, ConnectionClosed
try:
async with connect(...) as conn:
async for event in conn:
if event.type == "error":
print(f"API Error: {event.error.code} - {event.error.message}")
except ConnectionClosed as e:
print(f"Connection closed: {e.code} - {e.reason}")
except ConnectionError as e:
print(f"Connection error: {e}")
Best Practices
-
This SDK is async-only; use
azure.ai.voicelive.aiothroughout. Do not try to pair it with sync clients from other Azure SDKs in the same call path — keep the whole request path async. -
Always use context managers for clients and async credentials. Wrap every connection in
async with connect(...) as conn:. For asyncDefaultAzureCredentialfromazure.identity.aio, also useasync with credential:so tokens and transports are cleaned up.
References
-
Detailed API Reference: See references/api-reference.md
-
Complete Examples: See references/examples.md
-
All Models & Types: See references/models.md
pip install azure-ai-voicelive aiohttp azure-identityRun this in your project — your agent picks the skill up automatically.
Installation
pip install azure-ai-voicelive aiohttp azure-identity
Quick Start
import asyncio
import os
from azure.ai.voicelive.aio import connect
from azure.identity.aio import DefaultAzureCredential
async def main():
async with connect(
endpoint=os.environ["AZURE_COGNITIVE_SERVICES_ENDPOINT"],
credential=DefaultAzureCredential(),
model="gpt-4o-realtime-preview",
credential_scopes=["https://cognitiveservices.azure.com/.default"]
) as conn:
# Update session with instructions
await conn.session.update(session={
"instructions": "You are a helpful assistant.",
"modalities": ["text", "audio"],
"voice": "alloy"
})
# Listen for events
async for event in conn:
print(f"Event: {event.type}")
if event.type == "response.audio_transcript.done":
print(f"Transcript: {event.transcript}")
elif event.type == "response.done":
break
asyncio.run(main())
Session Configuration
from azure.ai.voicelive.models import RequestSession, FunctionTool
await conn.session.update(session=RequestSession(
instructions="You are a helpful voice assistant.",
modalities=["text", "audio"],
voice="alloy", # or "echo", "shimmer", "sage", etc.
input_audio_format="pcm16",
output_audio_format="pcm16",
turn_detection={
"type": "server_vad",
"threshold": 0.5,
"prefix_padding_ms": 300,
"silence_duration_ms": 500
},
tools=[
FunctionTool(
type="function",
name="get_weather",
description="Get current weather",
parameters={
"type": "object",
"properties": {
"location": {"type": "string"}
},
"required": ["location"]
}
)
]
))
No common issues documented yet. If you hit a problem, the repository's GitHub Issues page is the best place to look.