Speech SDK

The Universal SDK for text-to-speech across all major providers

A lightweight, provider-agnostic TypeScript SDK. Zero lock-in. Runs in Node.js, Edge runtimes, and the browser.

Created and maintained by Jellypod.

Docs · Quick start · Providers · Streaming · Conversations · Timestamps

Features

• Universal — one generateSpeech() call across every supported provider.
• Streaming — streamSpeech() returns a standard ReadableStream<Uint8Array>.
• Conversations — generateConversation() produces multi-speaker audio from one or many providers.
• Word-level timestamps — native where available, forced alignment otherwise, plus SRT/WebVTT captions.
• Audio tags, pronunciations, voice cloning & voice design — handled per provider behind one API.
• Output control — volume normalization and wav / mp3 / pcm output.

Install

npm install @speech-sdk/core

[!TIP] Using an AI coding assistant? Give it full knowledge of this library: npx skills add Jellypod-Inc/speech-sdk --skill speech-sdk.

Quick start

import { generateSpeech } from '@speech-sdk/core';

const result = await generateSpeech({
  model: 'openai/gpt-4o-mini-tts',
  text: 'Hello from speech-sdk!',
  voice: 'alloy',
});

result.audio.uint8Array;  // Uint8Array
result.audio.base64;      // string (lazy)
result.audio.mediaType;   // "audio/mpeg"

Set the provider's env var (e.g. OPENAI_API_KEY) or pass apiKey. A bare provider id ('openai') uses its default model.

Need a custom baseURL, fetch, or several configurations of one provider? Use a factory instead of a string:

import { createOpenAI } from '@speech-sdk/core/providers';

const openai = createOpenAI({ apiKey: 'sk-...', baseURL: 'https://my-proxy.com/v1' });

await generateSpeech({ model: openai('gpt-4o-mini-tts'), text: 'Hello!', voice: 'alloy' });

Use instructions for non-spoken delivery direction ('warm and measured') on models that support it. Provider-specific parameters pass through untouched via providerOptions.

Supported providers

Provider	Prefix	Env var
OpenAI	openai	OPENAI_API_KEY
ElevenLabs	elevenlabs	ELEVENLABS_API_KEY
Google Gemini TTS	google	GOOGLE_API_KEY
Cartesia	cartesia	CARTESIA_API_KEY
Deepgram	deepgram	DEEPGRAM_API_KEY
HeyGen	heygen	HEYGEN_API_KEY
Hume	hume	HUME_API_KEY
Inworld	inworld	INWORLD_API_KEY
Fish Audio	fish-audio	FISH_AUDIO_API_KEY
Gradium	gradium	GRADIUM_API_KEY
Murf	murf	MURF_API_KEY
Resemble	resemble	RESEMBLE_API_KEY
fal

Providers can also route through Vercel AI Gateway with createVercelAIGatewayClient(). See the docs for per-provider models, voices, and caveats.

Streaming

import { streamSpeech } from '@speech-sdk/core';

const { audio, mediaType } = await streamSpeech({
  model: 'cartesia/sonic-3.5',
  text: 'Streaming straight to the client.',
  voice: 'voice-id',
});

return new Response(audio, { headers: { 'Content-Type': mediaType } });

streamConversation() streams native two-speaker dialogue on models that support it (e.g. Gemini 3.8).

Conversations

generateConversation() turns an ordered list of turns into one clip. Turns on a single multi-speaker model use its native dialogue endpoint; anything else is generated in parallel, level-matched, and stitched.

import { generateConversation } from '@speech-sdk/core';

const result = await generateConversation({
  turns: [
    { model: 'openai/tts-1',                      voice: 'nova',                 text: "Hi, I'm hosted by OpenAI." },
    { model: 'elevenlabs/eleven_multilingual_v2', voice: 'JBFqnCBsd6RMkjVDRZzb', text: "And I'm hosted by ElevenLabs." },
  ],
});

result.metadata.path; // 'native' | 'native-split' | 'stitch'

Pass timestamps: true, splitTurns: true to also get one sample-accurate clip per turn in result.turns.

以上为 README 的开头部分。其余内容请阅读原文。 查看完整 README ↗