Providers

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=<speech-resource-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://<region>.tts.speech.microsoft.com from region unless you provide endpoint or baseUrl.

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.