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

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.
```
AZURE_SPEECH_KEY=
```
AZURE_SPEECH_REGION=eastus

Select Azure Speech in messages.tts

{
  messages: {
    tts: {
      auto: "always",
      provider: "azure-speech",
      providers: {
        "azure-speech": {
          voice: "en-US-JennyNeural",
          lang: "en-US",
        },
      },
    },
  },
}

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.

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

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://

.tts.speech.microsoft.comfromregionunless you provideendpointorbaseUrl`.

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.

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.

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.

Text-to-speech

TTS overview, providers, and messages.tts config.

Configuration

Full config reference including messages.tts settings.

Providers

All bundled OpenClaw providers.

Troubleshooting

Common issues and debugging steps.

Azure Speech

Getting started

Configuration options

Notes

Related