# Streaming

Consume Chat Completions, Responses, and Messages event streams safely.

Streaming reduces perceived latency and lets clients process output incrementally. Set `stream:true` and consume the response as `text/event-stream`.

## Chat Completions

```bash
curl -N https://api.koscompute.com/v1/chat/completions \
  -H "Authorization: Bearer $KOSCOMPUTE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "qwen/qwen3.8-27b",
    "messages": [{"role": "user", "content": "Write a four-line poem about compilers."}],
    "stream": true,
    "stream_options": {"include_usage": true},
    "max_completion_tokens": 160
  }'
```

Each SSE frame begins with `data:`. Parse complete frames rather than network packets. The stream normally ends with `data: [DONE]`. Usage can appear in the final chunk when requested; intermediate chunks may have no usage.

## Responses and Messages

Responses emits named lifecycle events; do not treat every delta as plain text. Anthropic Messages emits its own event names and typed content-block deltas. Use the SDK parser for the protocol you selected.

## Production handling

- Disable proxy buffering in your own reverse proxy.
- Apply an idle timeout longer than expected pauses during reasoning.
- Accumulate tool argument fragments before parsing JSON.
- Treat a client disconnect as cancellation and avoid blindly replaying a non-idempotent workflow.
- If the connection ends without a normal terminal event, regard the result as incomplete.

Once response headers are sent, the server cannot replace HTTP `200` with a later `5xx`. See [streaming failures](/docs/reliability/streaming-failures/).