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Telnyx Voice: STT — Documentation Index

STT documentation within the Voice section of the Telnyx developer docs (https://developers.telnyx.com). Root index: https://developers.telnyx.com/llms.txt · Voice index: https://developers.telnyx.com/development/llms/voice-llms-txt.md · Full content for this subsection: https://developers.telnyx.com/development/llms/voice-stt-llms-full-txt.md

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  • Overview: Real-time and batch audio transcription via WebSocket, REST, or in-call.
  • Quickstart: Stream audio to Telnyx Speech-to-Text and see live transcripts in under 5 minutes with this end-to-end Python and JavaScript quickstart.
  • Models: Compare Telnyx Speech-to-Text engines and models — Deepgram, Whisper, Google, Azure, xAI, AssemblyAI, Speechmatics, Soniox, Parakeet, Reson8 — by accuracy, latency, language coverage, and price.
  • Migration: Migrate from Deepgram, AssemblyAI, Google, or other speech-to-text providers to Telnyx STT in minutes by changing only two to three lines of code.

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WebSocket

  • Lifecycle: How the Telnyx Speech-to-Text WebSocket endpoint works for real-time streaming, including connection, audio frames, transcript messages, and shutdown.
  • Overview: Reference for query parameters on the Telnyx Speech-to-Text WebSocket endpoint, including engine, model, language, and redaction options.
  • Audio Formats: Supported audio input formats, sample rates, and engine compatibility for the Telnyx Speech-to-Text WebSocket streaming endpoint and binary frames.
  • Engines & Models: Available speech-to-text engines and models on Telnyx — Deepgram, Telnyx native, Google, Azure, xAI, AssemblyAI, Speechmatics, Soniox, Parakeet, Reson8 — selectable via query parameters.
  • End-of-Turn Detection: Flux end-of-turn detection parameters for voice agent turn-taking.
  • Language: Configure the language for Telnyx Speech-to-Text WebSocket streaming using BCP-47 codes, with per-engine differences in supported languages and behavior.
  • Interim Results: Enable interim results to receive partial transcripts as audio streams to the Telnyx Speech-to-Text WebSocket endpoint (Deepgram engine only).
  • Endpointing: Configure silence-based endpointing for utterance boundary detection on the Telnyx Speech-to-Text WebSocket endpoint (Deepgram, xAI, Google, Speechmatics, and Soniox).
  • Keyword Boosting: Boost recognition of specific terms (keyterm and keywords parameters).
  • Redaction: Automatically redact PII such as numbers, names, and SSNs from Telnyx streaming transcription results using Deepgram redaction parameters.
  • Messages: Reference for binary audio frames and JSON message types exchanged over the Telnyx Speech-to-Text WebSocket connection in both directions.
  • Errors: Error codes and troubleshooting tips for the Telnyx Speech-to-Text WebSocket endpoint, including invalid parameters, engine mismatches, and disconnects.
  • Examples: Complete Python and JavaScript code examples for streaming audio to the Telnyx Speech-to-Text WebSocket API and printing live transcription results.
  • Production Patterns: Reconnect, backoff, partial handling, buffering, and monitoring patterns for WebSocket STT.
  • Pricing: Pricing for Telnyx Speech-to-Text WebSocket streaming. Billed per minute of audio streamed in real time, with model-tier rates and volume discounts.

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REST API

  • Overview: Transcribe audio files synchronously with the Telnyx Speech-to-Text REST API by uploading a file or providing a public URL and receiving text.
  • Overview: Reference of all parameters for the Telnyx Speech-to-Text REST API — audio source, language, model, diarization, punctuation, and response options.
  • Models: Available speech-to-text models on the Telnyx STT REST API. Compare general, telephony, and specialty models by language, accuracy, and latency.
  • Audio Formats: Supported audio formats for the Telnyx Speech-to-Text REST API — WAV, MP3, FLAC, OGG, and more. Includes recommended sample rates and encodings.
  • Model Config: Model configuration options for the Telnyx Speech-to-Text REST API — biasing, hotwords, language hints, and per-request tuning of transcription accuracy.
  • Response Format: Response format reference for the Telnyx Speech-to-Text REST API — transcript text, words, timestamps, confidence, and per-channel diarization fields.
  • Pricing: Pricing for the Telnyx Speech-to-Text REST API. Billed per minute of audio processed, with model-tier rates and volume discounts available on request.

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In-Call

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API Reference (STT)

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Audio

  • Transcribe speech to text: Transcribe speech to text. This endpoint is consistent with the OpenAI Transcription API and may be used with the OpenAI JS or Python SDK.