Streaming · Docs

Set stream: true to receive tokens as server-sent events (SSE) instead of waiting for the full response.

stream = client.chat.completions.create(
    model="deepseek-ai/DeepSeek-V4.1-Flash",
    messages=[{"role": "user", "content": "Write a haiku about rivers."}],
    stream=True,
    stream_options={"include_usage": True},
)
for chunk in stream:
    if chunk.choices and chunk.choices[0].delta.content:
        print(chunk.choices[0].delta.content, end="", flush=True)
    if chunk.usage:
        print("\n", chunk.usage)

What to expect

Each event is a data: line containing a chat completion chunk; the stream ends with data: [DONE].
With stream_options.include_usage, the final chunk carries the usage object. Kurrens always reports usage for streamed requests.
Reasoning models may send SSE comment lines (: keep-alive) while they think. Clients should ignore them — they keep the connection from timing out.
If an error occurs mid-stream, a final event contains an error object before the stream closes.

Cancelling

Closing the connection cancels generation. You’re billed only for tokens generated before cancellation.