Azure Speech is a bundled Azure AI Speech text-to-speech provider. OpenClaw
calls the Azure Speech REST API directly with SSML, synthesizing MP3 for
standard replies, native Ogg/Opus for voice notes, and 8 kHz mulaw for
telephony channels such as Voice Call. The request sends the provider-owned
output format through the X-Microsoft-OutputFormat header.
| Detail | Value |
|---|---|
| Provider ID | azure-speech (alias: azure) |
| Website | Azure AI Speech |
| Docs | Speech REST text-to-speech |
| Auth | AZURE_SPEECH_KEY plus AZURE_SPEECH_REGION |
| Default voice | en-US-JennyNeural |
| Default file output | audio-24khz-48kbitrate-mono-mp3 |
| Default voice-note file | ogg-24khz-16bit-mono-opus |
Getting started
```
AZURE_SPEECH_KEY=<speech-resource-key>
AZURE_SPEECH_REGION=eastus
```
Configuration options
All options live under messages.tts.providers["azure-speech"].
| Option | Description |
|---|---|
apiKey |
Azure Speech resource key. Falls back to AZURE_SPEECH_KEY, AZURE_SPEECH_API_KEY, or SPEECH_KEY. |
region |
Azure Speech resource region. Falls back to AZURE_SPEECH_REGION or SPEECH_REGION. |
endpoint |
Optional Azure Speech endpoint override. Falls back to trusted AZURE_SPEECH_ENDPOINT. |
baseUrl |
Optional Azure Speech base URL override. |
voice |
Azure voice ShortName (default en-US-JennyNeural). Legacy alias: voiceId. |
lang |
SSML language code (default en-US). |
outputFormat |
Audio-file output format (default audio-24khz-48kbitrate-mono-mp3). |
voiceNoteOutputFormat |
Voice-note output format (default ogg-24khz-16bit-mono-opus). |
timeoutMs |
Request timeout override in milliseconds. Falls back to the global messages.tts.timeoutMs. |
The provider is considered configured once apiKey is set plus one of
region, endpoint, or baseUrl. Env vars are only checked as a fallback
for config keys left unset. Workspace .env files cannot set
AZURE_SPEECH_ENDPOINT; use the process environment, global runtime dotenv,
or explicit config for endpoint routing.
Notes
Related
Source: docs/providers/azure-speech.md