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+.

Install

openai-tts ships in the base install.

npm install getpatter

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();

# See python-sdk/providers/openai-tts for the Python twin.

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 });

Models and rates

OpenAI TTS bills per 1,000 characters synthesized. Per-model rates (defaults from getpatter/pricing):

Model	Rate / 1k chars	Notes
`tts-1`	$0.015	Fast, telephony-friendly.
`tts-1-hd`	$0.030	Higher fidelity — heavier.
`gpt-4o-mini-tts` (default)	$0.012	Accepts `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: ... } } } } }).)

Voices

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

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.

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.

Options

Option	Default	Notes
`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]`.
`antiAlias`	`false`	Enable an anti-aliasing LPF ahead of the 3:2 decimation — cleaner audio on sibilants / fricatives.

​OpenAI TTS

​Install

​Usage

​Models and rates

​Voices

​Languages

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

​Options

OpenAI TTS

Install

Usage

Models and rates

Voices

Languages

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

Options