更新日: 2026-06-06

Create Chat Completion

POST /v1/chat/completions

Generates model responses from a message list and supports both non-streaming and streaming output. This page only documents common behavior revalidated against Crazyrouter production on 2026-03-23.

Authentication

Authorization: Bearer YOUR_API_KEY

Core parameters

Parameter	Type	Required	Meaning
`model`	string	Yes	Model name such as `gpt-5.5`, `claude-opus-4-8`, or `gemini-3.1-pro`
`messages`	array	Yes	Message list
`stream`	boolean	No	Whether to stream output
`max_tokens`	integer	No	Maximum output tokens
`temperature`	number	No	Sampling temperature
`response_format`	object	No	Structured output constraint
`tools`	array	No	Tool list
`tool_choice`	string\|object	No	Tool-selection strategy
`stream_options`	object	No	Streaming extras such as `include_usage`

Optional parameter support varies by model. Client code should rely on the stable common fields first rather than assuming every model supports the same advanced options.

Non-streaming request

cURL

curl https://api.crazyrouter.com/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "gpt-5.5",
    "messages": [
      {
        "role": "system",
        "content": "You are a helpful assistant."
      },
      {
        "role": "user",
        "content": "Explain artificial intelligence in one sentence."
      }
    ],
    "max_tokens": 64
  }'

Typical production shape:

{
  "object": "chat.completion",
  "model": "gpt-5.5",
  "choices": [
    {
      "message": {
        "role": "assistant",
        "content": "...",
        "reasoning_content": null,
        "tool_calls": null
      },
      "finish_reason": "stop"
    }
  ]
}

Important interpretation

message.content is the most stable final-text field
message.tool_calls only appears when the model is requesting tool execution
message.reasoning_content may exist as a key, but should not currently be treated as guaranteed usable content

Streaming request

cURL

curl https://api.crazyrouter.com/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "gpt-5.5",
    "messages": [
      {
        "role": "user",
        "content": "Explain AI in one short sentence."
      }
    ],
    "stream": true,
    "stream_options": {
      "include_usage": true
    },
    "max_tokens": 64
  }'

This production recheck confirmed that:

streaming returns chat.completion.chunk
SSE chunks are sent as data: ...
the stream still ends with data: [DONE]

Observed SSE shape:

data: {"object":"chat.completion.chunk","model":"gpt-5.5","choices":[{"delta":{"role":"assistant","content":"AI","reasoning_content":null,"tool_calls":null}}]}

data: [DONE]

Python example

Python

from openai import OpenAI

client = OpenAI(
    api_key="YOUR_API_KEY",
    base_url="https://api.crazyrouter.com/v1"
)

stream = client.chat.completions.create(
    model="gpt-5.5",
    messages=[
        {"role": "user", "content": "Explain AI in one short sentence."}
    ],
    stream=True,
    stream_options={"include_usage": True},
    max_tokens=64
)

for chunk in stream:
    delta = chunk.choices[0].delta
    if delta.content is not None:
        print(delta.content, end="")

Current recommendation

For normal text chat, use /v1/chat/completions
For reasoning summaries or OpenAI-style web search, prefer /v1/responses
For more specific capability guarantees, use the dedicated capability pages rather than this generic endpoint page

Chat Completion Object チャット画像認識

Chat - OpenAI

Chat - Claude

Chat - Gemini

Chat - Responses API

画像生成

動画生成

音声

埋め込み & リランキング

その他の API

リファレンス

Create Chat Completion

Create Chat Completion

Authentication

Core parameters

Non-streaming request

Important interpretation

Streaming request

Python example

Current recommendation

​Create Chat Completion

​Authentication

​Core parameters

​Non-streaming request

​Important interpretation

​Streaming request

​Python example

​Current recommendation

Create Chat Completion

Authentication

Core parameters

Non-streaming request

Important interpretation

Streaming request

Python example

Current recommendation