OpenAI Chat Completions API Compatibility

Please refer to Speech Synthesis (MiMo-TTS Series) - OpenAI API Compatibility for the protocol documentation of the MiMo-TTS series models.

Request Address

https://api.xiaomimimo.com/v1/chat/completions

Request Headers

The API supports the following two authentication methods. Please choose one and add it to the request headers:

api-key: $MIMO_API_KEY
Content-Type: application/json

Request body

messagesarrayRequired
The current conversation message list.
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Developer-provided instructions that the model should follow, regardless of messages sent by the user.
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messages.contentstring | arrayRequired
The contents of the developer message.
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The contents of the developer message.
messages.rolestringRequired
The role of the message author.
Available options: developer
messages.namestring
An optional name for the participant. Provides the model information to differentiate between participants of the same role.
modelstringRequired
Model ID is used to generate the response.
Available options: mimo-v2.5-pro, mimo-v2.5
frequency_penaltynumber | nullDefault: 0
Number between -2.0 and 2.0. Positive values penalize new tokens based on their existing frequency in the text so far, decreasing the model's likelihood to repeat the same line verbatim.
Required range: [-2.0, 2.0]
max_completion_tokensinteger | null
An upper bound for the number of tokens that can be generated for a completion, including visible output tokens and reasoning tokens.
- mimo-v2.5-pro: default 131072
- mimo-v2.5: default 32768
Required range: [1, 131072]
presence_penaltynumber | nullDefault: 0
Number between -2.0 and 2.0. Positive values penalize new tokens based on whether they appear in the text so far, increasing the model's likelihood to talk about new topics.
Required range: [-2.0, 2.0]
response_formatobject
An object specifying the format that the model must output.
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Default response format. Used to generate text responses.
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response_format.typestringRequired
The type of response format being defined. Always text.
stopstring | array | nullDefault: null
Up to 4 sequences where the API will stop generating further tokens. The returned text will not contain the stop sequence.
streamboolean | nullDefault: false
If set to true, the model response data will be streamed to the client as it is generated using server-sent events.
thinkingobject
This parameter is used to control whether the model enables the chain of thought.
Note: During the multi-turn tool calls process in thinking mode, the model returns a reasoning_content field alongside tool_calls. To continue the conversation, it is recommended to keep all previous reasoning_content in the messages array for each subsequent request to achieve the best performance.
In thinking mode, the mimo-v2.5-pro, mimo-v2.5 models do not support customizing the temperature and top_p parameters. Even if these parameters are passed in, the actual effective values will be forcibly set by the model to its recommended default values of 1.0 and 0.95.
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thinking.typestringRequired
Whether to enable the chain of thought.
mimo-v2.5-pro, mimo-v2.5: default enabled
Available options: enabled, disabled
temperaturenumber
What sampling temperature to use, between 0 and 1.5. Higher values like 0.8 will make the output more random, while lower values like 0.2 will make it more focused and deterministic. We generally recommend altering this or top_p but not both.
In thinking mode, the mimo-v2.5-pro, mimo-v2.5 models do not support customizing the temperature parameter. Even if this parameter is passed in, it will be forcibly overridden and take effect with the model's recommended default value of 1.0.
- mimo-v2.5-pro, mimo-v2.5: default 1.0
Required range: [0, 1.5]
tool_choicestring
Controls how the model selects a tool.
Note: When a value other than auto is passed to tool_choice, the backend will remove this field by default, and the model response behavior will still be equivalent to the auto mode (this logic is subject to future adjustments).
Available options: auto
toolsarray
A list of tools the model may call. You can provide function tools.
Note: During the multi-turn tool calls process in thinking mode, the model returns a reasoning_content field alongside tool_calls. To continue the conversation, it is recommended to keep all previous reasoning_content in the messages array for each subsequent request to achieve the best performance.
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A function tool that can be used to generate a response.
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tools.functionobjectRequired
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tools.function.namestringRequired
The name of the tool function. Must be a-z, A-Z, 0-9, or contain underscores (_) and dashes (-), with a maximum length of 64.
Required string length: 1 - 64
tools.function.descriptionstring
A description of what the function does, used by the model to choose when and how to call the function.
tools.function.parametersobject
The parameters the functions accept, described as a JSON Schema object.
Omitting parameters defines a function with an empty parameter list.
tools.function.strictbooleanDefault: false
Whether to enable strict schema adherence when generating the function call. If set to true, the model will follow the exact schema defined in the parameters field. Only a subset of JSON Schema is supported when strict is true.
tools.typestringRequired
Tool type. Currently, only function is supported.
top_pnumberDefault: 0.95
The probability threshold for nucleus sampling, which controls the diversity of the text that the model generates. A higher top_p value results in more diverse text. A lower top_p value results in more deterministic text.
Because both temperature and top_p control the diversity of the generated text, we recommend that you set only one of them.
In thinking mode, the mimo-v2.5-pro, mimo-v2.5 models do not support customizing the top_p parameter. Even if this parameter is passed in, it will be forcibly overridden and take effect with the model's recommended default value of 0.95.
Required range: [0.01, 1.0]

Chat response object (non-streaming output)

choicesarray
A list of chat completion choices.
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choices.finish_reasonstring
The reason the model stopped generating tokens. This will be stop if the model hit a natural stop point or a provided stop sequence, length if the maximum number of tokens specified in the request was reached, tool_calls if the model called a tool, content_filter if content was omitted due to a flag from our content filters, repetition_truncation if the model detects repetition.
choices.indexinteger
The index of the choice in the list of choices.
choices.messageobject
A chat completion message generated by the model.
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choices.message.contentstring
The contents of the message.
choices.message.reasoning_contentstring
The reasoning contents of the assistant message, before the final answer.
choices.message.rolestring
The role of the author of this message.
choices.message.tool_callsarray
After a function call is initiated, the model returns the tool to be called and the parameters that are Required for the call. This parameter can contain one or more tool response objects.
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A call to a function tool created by the model.
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choices.message.tool_calls.functionobject
The function that the model called.
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choices.message.tool_calls.function.argumentsstring
The arguments to call the function with, as generated by the model in JSON format. Note that the model does not always generate valid JSON, and may hallucinate parameters not defined by your function schema. Validate the arguments in your code before calling your function.
choices.message.tool_calls.function.namestring
The name of the function to call.
choices.message.tool_calls.idstring
The ID of the tool call.
choices.message.tool_calls.typestring
The type of the tool. Currently, only function is supported.
choices.message.annotationsarray
After web search, the model returns annotations for all referenced URLs.
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A call to a web search tool created by the model.
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choices.message.annotations.logo_urlstring
Logo url.
choices.message.annotations.publish_timestring
Publish time.
choices.message.annotations.site_namestring
Site name.
choices.message.annotations.summarystring
Summary.
choices.message.annotations.titlestring
Title.
choices.message.annotations.typestring
Type.
choices.message.annotations.urlstring
Url.
choices.message.error_messagestring
Error message of web search.
createdinteger
The Unix timestamp (in seconds) of when the chat completion was created.
idstring
A unique identifier for the chat completion.
modelstring
The model to generate the completion.
objectstring
The object type, which is always chat.completion.
usageobject | null
Usage statistics for the completion request.
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usage.completion_tokensinteger
Number of tokens in the generated completion.
usage.prompt_tokensinteger
Number of tokens in the prompt.
usage.total_tokensinteger
Total number of tokens used in the request (prompt + completion).
usage.completion_tokens_detailsobject
Breakdown of tokens used in a completion.
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usage.completion_tokens_details.reasoning_tokensinteger
Tokens generated by the model for reasoning.
usage.prompt_tokens_detailsobject
Breakdown of tokens used in the prompt.
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usage.prompt_tokens_details.cached_tokensinteger
Number of tokens served from cache.
usage.prompt_tokens_details.audio_tokensinteger
Audio input tokens present in the prompt.
usage.prompt_tokens_details.image_tokensinteger
Image input tokens present in the prompt.
usage.prompt_tokens_details.video_tokensinteger
Video input tokens present in the prompt.
usage.web_search_usageobject
Detailed usage of the web search API.
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usage.web_search_usage.tool_usageinteger
Number of API calls in web search.
usage.web_search_usage.page_usageinteger
Number of web pages returned by the web search API.

Chat response chunk object (streaming output)

choicesarray
A list of chat completion choices.
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choices.deltaobject
A chat completion delta generated by streamed model responses.
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choices.delta.contentstring
The contents of the chunk message.
choices.delta.reasoning_contentstring
The reasoning contents of the assistant message, before the final answer.
choices.delta.rolestring
The role of the author of this message.
choices.delta.tool_callsarray
The tools to be called by the model and the parameters Required for the calls. It can contain one or more tool response objects.
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choices.delta.tool_calls.indexinteger
The index of the called tool in the tool_calls list, starting from 0.
choices.delta.tool_calls.functionobject
The function to be called.
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choices.delta.tool_calls.function.argumentsstring
The arguments to call the function with, as generated by the model in JSON format. Note that the model does not always generate valid JSON, and may hallucinate parameters not defined by your function schema. Validate the arguments in your code before calling your function.
choices.delta.tool_calls.function.namestring
The name of the function to call.
choices.delta.tool_calls.idstring
The ID of the tool call.
choices.delta.tool_calls.typestring
The type of the tool. Currently, only function is supported.
choices.delta.annotationsarray
After web search, the model returns annotations for all referenced URLs.
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A call to a web search tool created by the model.
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choices.delta.annotations.logo_urlstring
Logo url.
choices.delta.annotations.publish_timestring
Publish time.
choices.delta.annotations.site_namestring
Site name.
choices.delta.annotations.summarystring
Summary.
choices.delta.annotations.titlestring
Title.
choices.delta.annotations.typestring
Type.
choices.delta.annotations.urlstring
Url.
choices.delta.error_messagestring
Error message of web search.
choices.finish_reasonstring | null
The reason the model stopped generating tokens. This will be stop if the model hit a natural stop point or a provided stop sequence, length if the maximum number of tokens specified in the request was reached, tool_calls if the model called a tool, content_filter if content was omitted due to a flag from our content filters, repetition_truncation if the model detects repetition.
choices.indexinteger
The index of the choice in the list of choices.
createdinteger
The Unix timestamp (in seconds) of when the chat completion was created. Each chunk has the same timestamp.
idstring
A unique identifier for the chat completion. Each chunk has the same ID.
modelstring
The model to generate the completion.
objectstring
The object type, which is always chat.completion.chunk.
usageobject | null
Usage statistics for the completion request.
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usage.completion_tokensinteger
Number of tokens in the generated completion.
usage.prompt_tokensinteger
Number of tokens in the prompt.
usage.total_tokensinteger
Total number of tokens used in the request (prompt + completion).
usage.completion_tokens_detailsobject
Breakdown of tokens used in a completion.
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usage.completion_tokens_details.reasoning_tokensinteger
Tokens generated by the model for reasoning.
usage.prompt_tokens_detailsobject
Breakdown of tokens used in the prompt.
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usage.prompt_tokens_details.cached_tokensinteger
Number of tokens served from cache.
usage.prompt_tokens_details.audio_tokensinteger
Audio input tokens present in the prompt.
usage.prompt_tokens_details.image_tokensinteger
Image input tokens present in the prompt.
usage.prompt_tokens_details.video_tokensinteger
Video input tokens present in the prompt.
usage.web_search_usageobject
Detailed usage of the web search API.
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usage.web_search_usage.tool_usageinteger
Number of API calls in web search.
usage.web_search_usage.page_usageinteger
Number of web pages returned by the web search API.

curl --location --request POST 'https://api.xiaomimimo.com/v1/chat/completions' \
--header "api-key: $MIMO_API_KEY" \
--header "Content-Type: application/json" \
--data-raw '{
    "model": "mimo-v2.5-pro",
    "messages": [
        {
            "role": "system",
            "content": "You are MiMo, an AI assistant developed by Xiaomi. Today is date: Tuesday, December 16, 2025. Your knowledge cutoff date is December 2024."
        },
        {
            "role": "user",
            "content": "please introduce yourself"
        }
    ],
    "max_completion_tokens": 1024,
    "temperature": 1.0,
    "top_p": 0.95,
    "stream": false,
    "stop": null,
    "frequency_penalty": 0,
    "presence_penalty": 0,
    "thinking": {
        "type": "disabled"
    }
}'

response

{
    "id": "8b51f9e0515949cb8207fbd35ea6ea5c",
    "choices": [
        {
            "finish_reason": "stop",
            "index": 0,
            "message": {
                "content": "Hello! I'm MiMo, Xiaomi's AI assistant created by the Xiaomi LLM-Core team. I'm here to chat, help answer questions, and assist with various tasks—whether it's providing information, brainstorming ideas, or just having a friendly conversation. Feel free to ask me anything, and I'll do my best to help! 😊",
                "role": "assistant",
                "tool_calls": null
            }
        }
    ],
    "created": 1776848906,
    "model": "mimo-v2.5-pro",
    "object": "chat.completion",
    "usage": {
        "completion_tokens": 72,
        "prompt_tokens": 57,
        "total_tokens": 129,
        "completion_tokens_details": {
            "reasoning_tokens": 0
        },
        "prompt_tokens_details": null
    }
}

Update Time July 17, 2026

curl --location --request POST 'https://api.xiaomimimo.com/v1/chat/completions' \
--header "api-key: $MIMO_API_KEY" \
--header "Content-Type: application/json" \
--data-raw '{
    "model": "mimo-v2.5-pro",
    "messages": [
        {
            "role": "system",
            "content": "You are MiMo, an AI assistant developed by Xiaomi. Today is date: Tuesday, December 16, 2025. Your knowledge cutoff date is December 2024."
        },
        {
            "role": "user",
            "content": "please introduce yourself"
        }
    ],
    "max_completion_tokens": 1024,
    "temperature": 1.0,
    "top_p": 0.95,
    "stream": false,
    "stop": null,
    "frequency_penalty": 0,
    "presence_penalty": 0,
    "thinking": {
        "type": "disabled"
    }
}'

response

{
    "id": "8b51f9e0515949cb8207fbd35ea6ea5c",
    "choices": [
        {
            "finish_reason": "stop",
            "index": 0,
            "message": {
                "content": "Hello! I'm MiMo, Xiaomi's AI assistant created by the Xiaomi LLM-Core team. I'm here to chat, help answer questions, and assist with various tasks—whether it's providing information, brainstorming ideas, or just having a friendly conversation. Feel free to ask me anything, and I'll do my best to help! 😊",
                "role": "assistant",
                "tool_calls": null
            }
        }
    ],
    "created": 1776848906,
    "model": "mimo-v2.5-pro",
    "object": "chat.completion",
    "usage": {
        "completion_tokens": 72,
        "prompt_tokens": 57,
        "total_tokens": 129,
        "completion_tokens_details": {
            "reasoning_tokens": 0
        },
        "prompt_tokens_details": null
    }
}