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

# Streaming example

> Render incremental Chat Completions output by parsing Yelu Server-Sent Events.

This complete example requests a stream and prints each text delta. See [Streaming responses](/en/guides/streaming) for production parser and cancellation guidance.

<CodeGroup>
  ```bash Curl theme={"theme":{"light":"github-light","dark":"github-dark"}}
  curl -N https://api.yelu.ai/v1/chat/completions \
    -H "Authorization: Bearer $YELU_API_KEY" \
    -H "Content-Type: application/json" \
    -d '{"model":"gpt-4o-mini","messages":[{"role":"user","content":"List three API design principles."}],"stream":true}'
  ```

  ```javascript JavaScript theme={"theme":{"light":"github-light","dark":"github-dark"}}
  const response = await fetch('https://api.yelu.ai/v1/chat/completions', {
    method: 'POST',
    headers: { Authorization: `Bearer ${process.env.YELU_API_KEY}`, 'Content-Type': 'application/json' },
    body: JSON.stringify({
      model: 'gpt-4o-mini',
      messages: [{ role: 'user', content: 'List three API design principles.' }],
      stream: true,
    }),
  });
  if (!response.ok || !response.body) throw new Error(await response.text());

  const decoder = new TextDecoder();
  let buffer = '';
  for await (const bytes of response.body) {
    buffer += decoder.decode(bytes, { stream: true });
    const frames = buffer.split('\n\n');
    buffer = frames.pop() ?? '';
    for (const frame of frames) {
      const line = frame.split('\n').find((value) => value.startsWith('data: '));
      if (!line) continue;
      const payload = line.slice(6).trim();
      if (payload === '[DONE]') continue;
      process.stdout.write(JSON.parse(payload).choices?.[0]?.delta?.content ?? '');
    }
  }
  ```

  ```python Python theme={"theme":{"light":"github-light","dark":"github-dark"}}
  import json
  import os
  import requests

  with requests.post(
      "https://api.yelu.ai/v1/chat/completions",
      headers={"Authorization": f"Bearer {os.environ['YELU_API_KEY']}"},
      json={
          "model": "gpt-4o-mini",
          "messages": [{"role": "user", "content": "List three API design principles."}],
          "stream": True,
      },
      stream=True,
      timeout=(10, 120),
  ) as response:
      response.raise_for_status()
      for line in response.iter_lines(decode_unicode=True):
          if not line or not line.startswith("data: "):
              continue
          payload = line[6:].strip()
          if payload == "[DONE]":
              break
          print(json.loads(payload).get("choices", [{}])[0].get("delta", {}).get("content", ""), end="", flush=True)
  ```
</CodeGroup>