defuss-openai

A tiny OpenAI client built directly on top of the standard fetch() API.

Goals

• 0 runtime dependencies
• No classes
• No fetch patching
• Works anywhere fetch works
• Streaming support for chat/completions
• Audio/TTS support via standard Response streams
• Only the types this package actually needs
• Tool calling support

Supported endpoints

• POST /v1/chat/completions
• POST /v1/embeddings
• POST /v1/moderations
• POST /v1/audio/speech

Install

npm install defuss-openai

Requires a runtime with native fetch, ReadableStream, AbortController, and TextDecoder.

Usage

import { createClient } from 'defuss-openai';

const openai = createClient({
  baseUrl: 'http://localhost:8430/v1',
});

const chat = await openai.createChatCompletion({
  model: 'prism-ml/Bonsai-8B-mlx-1bit',
  messages: [{ role: 'user', content: 'hello' }],
});

console.log(chat.choices[0]?.message?.content);

Streaming chat completions

const stream = await openai.streamChatCompletion({
  model: 'prism-ml/Bonsai-8B-mlx-1bit',
  messages: [{ role: 'user', content: 'count to 3' }],
});

for await (const chunk of stream) {
  process.stdout.write(chunk.choices[0]?.delta?.content ?? '');
}

TTS / speech

createSpeech() returns the raw Response. That keeps the API isomorphic and lets you choose how to consume the audio.

const response = await openai.createSpeech({
  model: 'gpt-4o-mini-tts',
  voice: 'alloy',
  input: 'hello from a tiny client',
});

const audio = await response.arrayBuffer();

Or stream it:

const stream = await openai.createSpeechStream({
  model: 'gpt-4o-mini-tts',
  voice: 'alloy',
  input: 'hello from a tiny client',
});

for await (const chunk of stream) {
  console.log(chunk.length);
}

API

createClient(config?: ClientConfig): OpenAIClient

The returned client is a frozen plain object with these methods:

• createChatCompletion(params, opts?)
• streamChatCompletion(params, opts?)
• createEmbeddings(params, opts?)
• createModeration(params, opts?)
• createSpeech(params, opts?)
• createSpeechBuffer(params, opts?)
• createSpeechStream(params, opts?)

Why this shape?

The official SDK is broader and more feature-rich. This package is intentionally narrower: flat API, standard fetch semantics, tiny surface area, and no generated type dump.

Browser note

This library works in browsers, but shipping a secret OpenAI API key to the browser is usually a bad idea. Use a backend or edge proxy unless you fully understand the trade-offs.

Running tests

The e2e tests run against a local OpenAI-compatible inference server. You need Bonsai-8B-mlx-1bit-server running on http://127.0.0.1:8430:

# clone and start the server (requires macOS with Apple Silicon)
git clone https://github.com/kyr0/Bonsai-8B-mlx-1bit-server.git
cd Bonsai-8B-mlx-1bit-server
make setup && make start

Then run the tests:

# Node.js + browser (Playwright)
bun run test

# Node.js only
bun run test:e2e

# Browser only
bun run test:e2e:browser

License

MIT