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POST
/
v1
/
chat
/
completions
Create Chat Completion
curl --request POST \
  --url https://api.moonshot.ai/v1/chat/completions \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "messages": [
    {
      "role": "system",
      "content": "<string>",
      "name": null,
      "partial": false
    }
  ],
  "model": "kimi-k2.5"
}
'
{
  "id": "<string>",
  "object": "chat.completion",
  "created": 123,
  "model": "<string>",
  "choices": [
    {
      "index": 123,
      "message": {
        "role": "assistant",
        "content": "<string>",
        "tool_calls": [
          {
            "id": "<string>",
            "type": "function",
            "function": {
              "name": "<string>",
              "arguments": "<string>"
            }
          }
        ]
      },
      "finish_reason": "stop"
    }
  ],
  "usage": {
    "prompt_tokens": 123,
    "completion_tokens": 123,
    "total_tokens": 123
  }
}
Create a chat completion request. The model generates a response based on the provided message list.
The content field supports the following forms:
  • Plain text string: "Hello"
  • Array of objects: [{"type": "text", "text": "..."}, {"type": "image_url", "image_url": {"url": "..."}}]
  • [{"type": "video_url", "video_url": {"url": "data:video/mp4;base64,..."}}]
The url field of image_url and video_url supports base64 format and ms://<file_id> format. See Use the Kimi Vision Model.

​
Example

{
    "model": "kimi-k2.5",
    "messages": [
        {
            "role": "system",
            "content": "You are Kimi, an AI assistant provided by Moonshot AI. You excel in Chinese and English conversations. You provide users with safe, helpful, and accurate answers. You refuse to answer any questions involving terrorism, racism, pornography, or violence. Moonshot AI is a proper noun and should not be translated into other languages."
        },
        {
            "role": "user",
            "content": [
                {
                    "type": "image_url",
                    "image_url": {
                        "url": "data:image/png;base64,iVBORw0KGgoAAAANSUhEUg..."
                    }
                },
                {
                    "type": "text",
                    "text": "Describe this image"
                }
            ]
        }
    ]
}

​
Image Content Field Description

When using Vision models, the message.content field changes from str to List[Object[str, any]]. Each element in the List has the following fields:
ParameterRequiredDescriptionType
typerequiredOnly supports text type (text) or image type (image_url)string
image_urlrequiredObject for transmitting imagesDict[str, any]
The image_url parameter fields:
ParameterRequiredDescriptionType
urlrequiredImage content specified via base64 encoding or file idstring

​
Usage Example

import os
import base64

from openai import OpenAI

client = OpenAI(
    api_key=os.environ.get("MOONSHOT_API_KEY"),
    base_url="https://api.moonshot.ai/v1",
)

# Encode the image to base64
with open("your_image_path", 'rb') as f:
    img_base = base64.b64encode(f.read()).decode('utf-8')

response = client.chat.completions.create(
    model="kimi-k2.5",
    messages=[
        {
            "role": "user",
            "content": [
                {
                    "type": "image_url",
                    "image_url": {
                        "url": f"data:image/jpeg;base64,{img_base}"
                    }
                },
                {
                    "type": "text",
                    "text": "Describe this image"
                }
            ]
        }
    ]
)
print(response.choices[0].message.content)

​
Non-streaming Response

{
    "id": "cmpl-04ea926191a14749b7f2c7a48a68abc6",
    "object": "chat.completion",
    "created": 1698999496,
    "model": "kimi-k2.5",
    "choices": [
        {
            "index": 0,
            "message": {
                "role": "assistant",
                "content": "Hello, Li Lei! 1+1 equals 2. If you have any other questions, feel free to ask!"
            },
            "finish_reason": "stop"
        }
    ],
    "usage": {
        "prompt_tokens": 19,
        "completion_tokens": 21,
        "total_tokens": 40,
        "cached_tokens": 10
    }
}

​
Streaming Response

data: {"id":"cmpl-xxx","object":"chat.completion.chunk","created":1698999575,"model":"kimi-k2.5","choices":[{"index":0,"delta":{"role":"assistant","content":""},"finish_reason":null}]}

data: {"id":"cmpl-xxx","object":"chat.completion.chunk","created":1698999575,"model":"kimi-k2.5","choices":[{"index":0,"delta":{"content":"Hello"},"finish_reason":null}]}

...

data: {"id":"cmpl-xxx","object":"chat.completion.chunk","created":1698999575,"model":"kimi-k2.5","choices":[{"index":0,"delta":{},"finish_reason":"stop","usage":{"prompt_tokens":19,"completion_tokens":13,"total_tokens":32}}]}

data: [DONE]

Authorizations

​
Authorization
string
header
required

The Authorization header expects a Bearer token. Use an MOONSHOT_API_KEY as the token. This is a server-side secret key. Generate one on the API keys page in your dashboard.

Body

application/json
​
messages
object[]
required

A list of messages in the conversation so far. Each element has the format {"role": "user", "content": "Hello"}. role supports system, user, or assistant. content must not be empty. The content field can be a string or a List[Dict] (for multimodal input).

​
model
enum<string>
default:kimi-k2.5
required

Model ID

Available options:
kimi-k2.5
​
max_tokens
integer

Deprecated, please refer to max_completion_tokens

​
max_completion_tokens
integer

The maximum number of tokens to generate for the chat completion. If not specified, defaults to a reasonable integer such as 1024. If the result reaches the maximum number of tokens without ending, the finish reason will be "length"; otherwise, it will be "stop". This refers to the length of tokens you expect us to return, not the total length of input plus output. If input plus max_completion_tokens exceeds the model context window, the API returns invalid_request_error.

​
response_format
object

Setting this to {"type": "json_object"} enables JSON mode, ensuring that the generated information is valid JSON. When you set response_format to {"type": "json_object"}, you must explicitly guide the model to output JSON-formatted content in the prompt and specify the exact format of the JSON, otherwise it may result in unexpected outcomes. Default is {"type": "text"}.

​
stop

Stop words, which will halt the output when a full match is found. The matched words themselves will not be output. A maximum of 5 strings is allowed, and each string must not exceed 32 bytes

​
stream
boolean
default:false

Whether to return the response in a streaming fashion. Default is false.

​
stream_options
object

Options for streaming responses

​
tools
object[]

A list of tools the model may call

Maximum array length: 128
​
prompt_cache_key
string

Used to cache responses for similar requests to optimize cache hit rates. For Coding Agents, this is typically a session id or task id representing a single session; if the session is exited and later resumed, this value should remain the same. For Kimi Code Plan, this field is required to improve cache hit rates. For other agents involving multi-turn conversations, it is also recommended to implement this field

​
safety_identifier
string

A stable identifier used to help detect users of your application that may be violating usage policies. The ID should be a string that uniquely identifies each user. It is recommended to hash the username or email address to avoid sending any identifying information

​
thinking
object

Controls if thinking is enabled for kimi-k2.5 model. Only available when model equals to kimi-k2.5. Optional parameter. Default value is {"type": "enabled"}.

Response

Chat completion response

​
id
string

Unique identifier for the completion

​
object
string

Object type

Example:

"chat.completion"

​
created
integer

Unix timestamp of when the completion was created

​
model
string

Model used for the completion

​
choices
object[]

List of completion choices

​
usage
object