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Documentation Index

Fetch the complete documentation index at: https://docs.getpatter.com/llms.txt

Use this file to discover all available pages before exploring further.

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OpenAI TTS

OpenAITTS is a Patter TTSProvider backed by OpenAI’s POST /v1/audio/speech endpoint. It streams 24 kHz PCM from OpenAI and resamples it to 16 kHz or 8 kHz on the fly so the telephony output path can forward bytes without an additional resample stage. Uses the platform fetch — no vendor SDK required, works on Node 18+.

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Install

openai-tts ships in the base install. 
npm install getpatter

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Usage

Use the namespaced import (getpatter/tts/openai) or the flat re-export (OpenAITTS). Both auto-resolve OPENAI_API_KEY from the environment when apiKey is omitted.
// Namespaced import
import * as openai from "getpatter/tts/openai";

const tts = new openai.TTS();                                    // reads OPENAI_API_KEY
const tts2 = new openai.TTS({ apiKey: "sk-...", voice: "nova", model: "tts-1-hd" });

// Flat alias (equivalent)
import { OpenAITTS } from "getpatter";

const tts3 = new OpenAITTS();
In an agent: 
// npx tsx example.ts
import { Patter, Twilio, DeepgramSTT, OpenAITTS } from "getpatter";

const phone = new Patter({ carrier: new Twilio(), phoneNumber: "+15550001234" });

const agent = phone.agent({
  stt: new DeepgramSTT(),                             // DEEPGRAM_API_KEY from env
  tts: new OpenAITTS({ voice: "nova" }),              // OPENAI_API_KEY from env
  systemPrompt: "You are a helpful assistant.",
});

await phone.serve({ agent });

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Models and rates

OpenAI TTS bills per 1,000 characters synthesized. Per-model rates (defaults from getpatter/pricing):
ModelRate / 1k charsNotes
tts-1$0.015Fast, telephony-friendly.
tts-1-hd$0.030Higher fidelity — heavier.
gpt-4o-mini-tts (default)$0.012Accepts instructions for voice direction.
(gpt-4o-mini-tts is billed by tokens upstream; published per 1k chars equivalent for parity with the rest of the table. Override via new Patter({ pricing: { openai_tts: { models: { "tts-1": { price: ... } } } } }).)

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Voices

Built-in voices accepted by all three models: alloy (default), ash, ballad, coral, echo, fable, nova, onyx, sage, shimmer, verse.

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Languages

OpenAI TTS automatically follows the language of the input text — no language parameter exists. The same voice can synthesize across most of OpenAI’s supported languages (English, Spanish, French, German, Italian, Portuguese, Japanese, Chinese, …) — see the OpenAI voice guide for the full coverage matrix.

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Voice direction (gpt-4o-mini-tts only)

Pass instructions to steer tone, pacing, and accent: 
const tts = new OpenAITTS({
  apiKey: "sk-...",
  model: "gpt-4o-mini-tts",
  voice: "sage",
  instructions: "Speak in a warm, empathetic tone, like a customer support specialist.",
});
tts-1 and tts-1-hd reject instructions with a 400 — the SDK silently drops the field for those models so you can swap freely.

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Options

OptionDefaultNotes
apiKey—Reads from OPENAI_API_KEY when omitted.
model"gpt-4o-mini-tts""tts-1", "tts-1-hd", "gpt-4o-mini-tts".
voice"alloy"Any of the 11 built-in voices above.
instructions—Voice-direction prompt (ignored for legacy models).
speed—Float in [0.25, 4.0].
antiAliasfalseEnable an anti-aliasing LPF ahead of the 3:2 decimation — cleaner audio on sibilants / fricatives.