Text-to-Speech

Models

Learn about latest Text-to-Speech models, changelog, and deprecations.

Soniox Text-to-Speech is built for the hardest parts of speech generation. It delivers native-speaker-quality speech in 60+ languages, with hallucination-free output and accurate pronunciation of alphanumerics such as phone numbers, email addresses, and IDs.

This page lists the currently available models, along with release notes and important updates.


Current models

Model
Type
Status
tts-rt-v2Real-timeActive
tts-rt-v1Real-timeDeprecated
Will be removed Aug 31, 2026

Aliases

Aliases provide a stable reference so you don’t need to change your code when newer versions are released.

AliasPoints toNotes
tts-rt-v1-previewtts-rt-v1

Changelog

Aug 11, 2026

Overview

Soniox TTS v2 is now generally available.

  • tts-rt-v2 is available to all API customers and deployed in all Soniox regions: US, EU, and JP.

Key improvements

  • Natural, expressive speech across more than 60 languages
  • Direct control over emotion, delivery, and vocal reactions through audio tags
  • High-fidelity voice cloning
  • Natural language switching within the same sentence
  • Even more precise pronunciation of names, terminology, numbers, codes, addresses, and identifiers
  • Reduced silence between sentences and punctuation for more responsive conversations

API compatibility

The tts-rt-v2 model is fully compatible with the existing tts-rt-v1 model and Soniox Text-to-Speech API. To upgrade, simply replace the model name in your API request: { "model": "tts-rt-v2" }

Deprecation notice

The tts-rt-v1 model will be removed on August 31, 2026. After August 31, 2026, requests using tts-rt-v1 will automatically route to tts-rt-v2 with no service interruption and no API changes required.

April 29, 2026

Overview

Soniox TTS is now generally available.

  • The preview model tts-rt-v1-preview is now available as the production model tts-rt-v1.
  • tts-rt-v1 is available to all API customers and deployed in all Soniox regions: US, EU, and JP.
  • For backward compatibility, tts-rt-v1-preview now points to tts-rt-v1 with no service interruption. We recommend updating your API requests to use tts-rt-v1.

April 23, 2026

Overview

tts-rt-v1-preview is the first Soniox Text-to-Speech model, released in preview to gather developer feedback and guide further improvements before general availability.

Key capabilities

  • Native-speaker-quality speech in 60+ languages
  • Hallucination-free generation, with no invented words, dropped content, or unexpected substitutions
  • Accurate rendering of alphanumerics such as email addresses, phone numbers, street addresses, IDs, and codes
  • Streaming generation before the sentence ends for ultra-low-latency voice systems
  • Multiple voices that work across all supported languages
  • Configurable audio formats, sample rates, and bitrates
  • Support for both WebSocket and REST APIs