Streaming

Enabling Streaming

Set stream: true in your chat completion request:

curl https://ghostmind.optdmsa.com/v1/chat/completions \
  -H "Authorization: Bearer sk-gm-..." \
  -H "Content-Type: application/json" \
  -d '{
    "model": "auto",
    "stream": true,
    "messages": [{"role": "user", "content": "Hello!"}]
  }'

SSE Format

The response is a stream of Server-Sent Events:

data: {"id":"chatcmpl-abc","object":"chat.completion.chunk","choices":[{"index":0,"delta":{"role":"assistant"},"finish_reason":null}]}

data: {"id":"chatcmpl-abc","object":"chat.completion.chunk","choices":[{"index":0,"delta":{"content":"Hello"},"finish_reason":null}]}

data: {"id":"chatcmpl-abc","object":"chat.completion.chunk","choices":[{"index":0,"delta":{"content":"!"},"finish_reason":null}]}

data: {"id":"chatcmpl-abc","object":"chat.completion.chunk","choices":[{"index":0,"delta":{},"finish_reason":"stop"}]}

data: [DONE]

Event Flow

1. First chunk — Contains delta.role: "assistant"
2. Content chunks — Contain delta.content with text fragments
3. Final chunk — Contains finish_reason: "stop"
4. [DONE] — Stream terminator

Error During Stream

If an error occurs mid-stream, an error event is sent:

data: {"error":{"message":"Upstream error","type":"upstream_error"}}

Client Example (JavaScript)

const response = await fetch("https://ghostmind.optdmsa.com/v1/chat/completions", {
  method: "POST",
  headers: {
    "Authorization": "Bearer sk-gm-...",
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    model: "auto",
    stream: true,
    messages: [{ role: "user", content: "Hello!" }],
  }),
});

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

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

  buffer += decoder.decode(value, { stream: true });
  const lines = buffer.split("\n");
  buffer = lines.pop();

  for (const line of lines) {
    if (line.startsWith("data: ")) {
      const data = line.slice(6);
      if (data === "[DONE]") return;
      const chunk = JSON.parse(data);
      const content = chunk.choices?.[0]?.delta?.content;
      if (content) process.stdout.write(content);
    }
  }
}

Next Steps

• Chat Completions API — API reference
• Handling Errors — Error handling