> ## Documentation Index
> Fetch the complete documentation index at: https://docs.tokenlab.sh/llms.txt
> Use this file to discover all available pages before exploring further.

# Streaming

> Implement real-time streaming responses

## Overview

Streaming lets you receive partial output as it is generated, which improves perceived latency and user experience.

For new OpenAI-style integrations, prefer **Responses streaming** first. If your framework still uses Chat Completions streaming, TokenLab supports that compatibility path too.

## Recommended: Responses Streaming

<CodeGroup>
  ```bash cURL theme={null}
  curl https://api.tokenlab.sh/v1/responses \
    -H "Authorization: Bearer sk-your-api-key" \
    -H "Content-Type: application/json" \
    -d '{
      "model": "gpt-5.4",
      "input": "Write a short poem.",
      "stream": true
    }'
  ```

  ```python Python theme={null}
  from openai import OpenAI

  client = OpenAI(
      api_key="sk-your-api-key",
      base_url="https://api.tokenlab.sh/v1"
  )

  stream = client.responses.create(
      model="gpt-5.4",
      input="Write a short poem.",
      stream=True
  )

  for event in stream:
      if event.type == "response.output_text.delta":
          print(event.delta, end="", flush=True)
  ```

  ```javascript JavaScript theme={null}
  import OpenAI from 'openai';

  const client = new OpenAI({
    apiKey: 'sk-your-api-key',
    baseURL: 'https://api.tokenlab.sh/v1'
  });

  const stream = await client.responses.create({
    model: 'gpt-5.4',
    input: 'Write a short poem.',
    stream: true
  });

  for await (const event of stream) {
    if (event.type === 'response.output_text.delta') {
      process.stdout.write(event.delta);
    }
  }
  ```
</CodeGroup>

## Chat Completions Streaming

If your framework still expects SSE chunks from `/v1/chat/completions`, that also works:

```python theme={null}
stream = client.chat.completions.create(
    model="gpt-4o",
    messages=[{"role": "user", "content": "Write a short poem"}],
    stream=True
)

for chunk in stream:
    content = chunk.choices[0].delta.content
    if content:
        print(content, end="", flush=True)
```

## Stream End Conditions

Typical completion conditions:

* `response.completed` for Responses API streams
* `finish_reason: "stop"` for Chat Completions streams
* `finish_reason: "length"` when a token limit is hit
* tool/function call events when the model wants to use tools

## Web App Pattern

```javascript theme={null}
async function streamChat(message) {
  const response = await fetch('https://api.tokenlab.sh/v1/chat/completions', {
    method: 'POST',
    headers: {
      'Authorization': 'Bearer sk-your-api-key',
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      model: 'gpt-4o',
      messages: [{ role: 'user', content: message }],
      stream: true
    })
  });

  const reader = response.body.getReader();
  const decoder = new TextDecoder();

  while (true) {
    const { done, value } = await reader.read();
    if (done) break;

    const chunk = decoder.decode(value);
    const lines = chunk.split('\\n').filter(line => line.startsWith('data: '));

    for (const line of lines) {
      const data = line.slice(6);
      if (data === '[DONE]') return;
      const parsed = JSON.parse(data);
      const content = parsed.choices?.[0]?.delta?.content;
      if (content) {
        document.getElementById('output').textContent += content;
      }
    }
  }
}
```

## Best Practices

<AccordionGroup>
  <Accordion title="Prefer Responses streaming for new builds">
    Use `/v1/responses` if your SDK or app already supports it. Keep `/v1/chat/completions` streaming for compatibility-driven integrations.
  </Accordion>

  <Accordion title="Flush output incrementally">
    Append delta chunks to the UI or terminal as they arrive rather than waiting for the full response.
  </Accordion>

  <Accordion title="Handle disconnects and retries">
    Treat network drops and upstream disconnects as normal failure modes and reconnect carefully for long-running sessions.
  </Accordion>
</AccordionGroup>