Azure Speech

Azure Speech is an Azure AI Speech text-to-speech provider. In OpenClaw it synthesizes outbound reply audio as MP3 by default, native Ogg/Opus for voice notes, and 8 kHz mulaw audio for telephony channels such as Voice Call.

OpenClaw uses the Azure Speech REST API directly with SSML and sends the provider-owned output format through X-Microsoft-OutputFormat.

Detail	Value
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

<Steps> <Step title="Create an Azure Speech resource"> In the Azure portal, create a Speech resource. Copy **KEY 1** from Resource Management > Keys and Endpoint, and copy the resource location such as `eastus`. </Step> <Step title="Select Azure Speech in messages.tts"> ```json5 { messages: { tts: { auto: "always", provider: "azure-speech", providers: { "azure-speech": { voice: "en-US-JennyNeural", lang: "en-US", }, }, }, }, } ``` </Step> <Step title="Send a message"> Send a reply through any connected channel. OpenClaw synthesizes the audio with Azure Speech and delivers MP3 for standard audio, or Ogg/Opus when the channel expects a voice note. </Step> </Steps>

Configuration options

Option	Path	Description
apiKey	messages.tts.providers.azure-speech.apiKey	Azure Speech resource key. Falls back to AZURE_SPEECH_KEY, AZURE_SPEECH_API_KEY, or SPEECH_KEY.
region	messages.tts.providers.azure-speech.region	Azure Speech resource region. Falls back to AZURE_SPEECH_REGION or SPEECH_REGION.
endpoint	messages.tts.providers.azure-speech.endpoint	Optional Azure Speech endpoint/base URL override.
baseUrl	messages.tts.providers.azure-speech.baseUrl	Optional Azure Speech base URL override.
voice	messages.tts.providers.azure-speech.voice	Azure voice ShortName (default en-US-JennyNeural).
lang	messages.tts.providers.azure-speech.lang	SSML language code (default en-US).
outputFormat	messages.tts.providers.azure-speech.outputFormat	Audio-file output format (default audio-24khz-48kbitrate-mono-mp3).
voiceNoteOutputFormat	messages.tts.providers.azure-speech.voiceNoteOutputFormat	Voice-note output format (default ogg-24khz-16bit-mono-opus).

Notes

<AccordionGroup> <Accordion title="Authentication"> Azure Speech uses a Speech resource key, not an Azure OpenAI key. The key is sent as `Ocp-Apim-Subscription-Key`; OpenClaw derives `https://<region>.tts.speech.microsoft.com` from `region` unless you provide `endpoint` or `baseUrl`. </Accordion> <Accordion title="Voice names"> Use the Azure Speech voice `ShortName` value, for example `en-US-JennyNeural`. The bundled provider can list voices through the same Speech resource and filters voices marked deprecated or retired. </Accordion> <Accordion title="Audio outputs"> Azure accepts output formats such as `audio-24khz-48kbitrate-mono-mp3`, `ogg-24khz-16bit-mono-opus`, and `riff-24khz-16bit-mono-pcm`. OpenClaw requests Ogg/Opus for `voice-note` targets so channels can send native voice bubbles without an extra MP3 conversion. </Accordion> <Accordion title="Alias"> `azure` is accepted as a provider alias for existing PRs and user config, but new config should use `azure-speech` to avoid confusion with Azure OpenAI model providers. </Accordion> </AccordionGroup>

Related

<CardGroup cols={2}> <Card title="Text-to-speech" href="/tools/tts" icon="waveform-lines"> TTS overview, providers, and `messages.tts` config. </Card> <Card title="Configuration" href="/gateway/configuration" icon="gear"> Full config reference including `messages.tts` settings. </Card> <Card title="Providers" href="/providers" icon="grid"> All bundled OpenClaw providers. </Card> <Card title="Troubleshooting" href="/help/troubleshooting" icon="wrench"> Common issues and debugging steps. </Card> </CardGroup>