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Soniox STT Now Available for Telnyx Voice AI

3, Jun 2026

Soniox STT is now available on Telnyx, giving voice AI teams another real-time speech-to-text option for live transcription. Developers can use Soniox for automatic language detection, streaming transcription, and voice agent workflows.

What's new

  • Soniox STT engine: Select Soniox as a speech-to-text provider for real-time transcription on Telnyx.
  • Automatic language detection: Use soniox/stt-rt-v4 without a language hint when caller language is not known in advance.
  • Real-time transcription: Use Soniox for WebSocket and Voice API transcription workflows.
  • Interim results: Stream partial transcripts before final results are available.
  • Voice agent turn-taking: Use endpointing to detect when a caller has finished speaking.

Why it matters

  • Voice AI agents rely on accurate transcripts to understand caller intent and route each turn correctly.
  • Callers may use different languages across conversations. Soniox gives teams another transcription option for workflows where language is not known before the call starts.
  • Adding Soniox through Telnyx gives developers more STT provider choice inside the same voice AI configuration path.
  • Keeping transcription configurable inside Telnyx helps teams test STT models without rebuilding the rest of the agent pipeline.

Example use cases

  • Customer support voice agents that need real-time transcripts across caller populations.
  • Healthcare intake agents that need to capture names, symptoms, medications, and alphanumeric identifiers.
  • Financial services agents that need to capture account details, addresses, and verification phrases.
  • Live captioning, meeting notes, and voice interfaces that need streaming transcription.

Getting started

  1. In Mission Control Portal, navigate to AI → Assistants → select your assistant → Voice tab.
  2. Scroll to Transcription and select Soniox as the STT model or provider.
  3. Test your assistant with real caller audio and confirm transcript quality before routing production traffic.

Configure Soniox STT with the Assistants API

You can also configure Soniox STT through the Assistants API by setting transcription.model to soniox/stt-rt-v4.

curl -X POST https://api.telnyx.com/v2/ai/assistants \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "soniox-stt-assistant",
    "model": "moonshotai/Kimi-K2.5",
    "instructions": "You are a voice assistant for live customer conversations.",
    "transcription": {
      "model": "soniox/stt-rt-v4",
      "language": "auto",
      "settings": {
        "interim_results": true,
        "enable_endpoint_detection": true,
        "max_endpoint_delay_ms": 1000
      }
    }
  }'

Learn more in the Telnyx Speech-to-Text models documentation.