xAI Grok TTS and STT Now Available via API

xAI Grok voices and transcription are now available through the Telnyx TTS and STT APIs, extending Grok support beyond Voice AI Assistants to standalone API usage.

What's New

• Grok TTS via API: Five expressive voices (Ara, Eve, Leo, Rex, Sal) now available through the TTS API, not just Voice AI Assistants. Supports Expressive Mode with inline speech tags for pauses, laughter, whispers, and emphasis.
• Grok STT via API: The xai/grok-stt model is now available for standalone speech-to-text transcription, adding multilingual auto-detection to the STT API lineup.

How It Works

Grok TTS voices use the format xAI.<voice_id> (e.g., xAI.eve, xAI.ara). Expressive Mode lets the AI model control tone and delivery during generation using inline speech tags, without hard-coding emotions into prompts.

Grok STT uses the model ID xai/grok-stt for real-time transcription with multilingual auto-detection.

Why It Matters

Developers building custom voice pipelines now have the same Grok voices and transcription available through the API that Mission Control users have had for Voice AI Assistants. This means Grok's expressive, multilingual capabilities work in any architecture, not just the managed assistant path.

Getting Started

Via the API:

• TTS: Use the xAI.<voice_id> format in your TTS requests. See the xAI Grok TTS documentation for voice IDs and Expressive Mode configuration.
• STT: Set model to xai/grok-stt in your STT API or WebSocket requests. See the transcription settings documentation for model details.

You can also access xAI Grok TTS and STT via Mission Control.