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What is Atlas TTS?

Atlas TTS is a fine-tuned text-to-speech voice model with a catalogue of natural, expressive English voices (list them live via /v1/models). It supports inline audio tags — laughs, sighs, breaths, pauses, and per-sentence emotional styles — so generated speech sounds like a performance, not a readout. Every voice is served through two front doors:

HTTP API

Drop-in OpenAI-compatible POST /v1/audio/speech. Point the OpenAI SDK at our base URL and it just works.

Streaming WebSocket

Low-latency, sentence-by-sentence audio frames for conversational and real-time apps.

Voices reference

Configuration parameters, environment variables, and usage examples.

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Capabilities

  • Expressive delivery — inline event tags (<|laugh|>, <|sigh|>, <|pause|> …) and sentence-level style wraps (excited, whispers, sarcastic, accents, …).
  • OpenAI compatibility — use the official OpenAI Python or Node SDK unchanged; only the base URL and API key differ.
  • Real-time streaming — a WebSocket protocol that returns one audio frame per sentence as it is synthesized.
  • Multiple output formats — wav, mp3, pcm, opus, and flac.
  • Per-request observability — every HTTP response carries x-upstream-ms and x-gateway-ms timing headers.

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Use cases

  • Conversational agents and voice assistants that need low first-audio latency.
  • Content production: narration, voiceovers, and character work with emotional range.
  • Product experiences that read dynamic text aloud with natural pacing.