Chat Completions

Updated: 2026-02-18

Overview

Generate conversational text replies, compatible with the OpenAI Chat Completions spec. Supports streaming, tool calls, and structured output (JSON Mode).

POST/chat/completions

Request Parameters

Parameter	Type	Required	Description
model	string	Required	Model ID, e.g. doubao-seed-2-0-lite-260215, deepseek-v3
messages	array	Required	List of chat messages. Each has a role and a content field
temperature	number	Optional	Sampling temperature in [0.0, 2.0], default 1.0. Higher is more creative
top_p	number	Optional	Nucleus sampling in [0.0, 1.0], default 1.0
max_tokens	integer	Optional	Max tokens to generate, default 4096; ceiling depends on the model
stream	boolean	Optional	Whether to stream the response, default false
tools	array	Optional	Function Calling tool list, following the OpenAI tools schema
response_format	object	Optional	Output format; pass { type: "json_object" } to enable JSON mode

Example

curl -X POST "https://www.starunion.net/v1/chat/completions" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "doubao-seed-2-0-lite-260215",
    "messages": [
      {"role": "user", "content": "Explain quantum entanglement in one sentence"}
    ]
  }'

Streaming

When stream is set to true, the server returns a Server-Sent Events (SSE) stream where each event is an incremental delta.

curl -X POST "https://www.starunion.net/v1/chat/completions" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "doubao-seed-2-0-lite-260215",
    "messages": [{"role": "user", "content": "Hello"}],
    "stream": true
  }'

Function Calling

Pass function definitions via the tools parameter. The model returns tool_calls when needed; your application runs the function and feeds the result back.

JSON

{
  "tool_calls": [
    {
      "id": "call_abc123",
      "type": "function",
      "function": {
        "name": "get_weather",
        "arguments": "{\"city\": \"Hangzhou\"}"
      }
    }
  ]
}

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