Create chat completion

ChatCompletion chat().completions().create(, )

POST/chat/completions

Starting a new project? We recommend trying Responses to take advantage of the latest OpenAI platform features. Compare Chat Completions with Responses.

Creates a model response for the given chat conversation. Learn more in the text generation, vision, and audio guides.

Parameter support can differ depending on the model used to generate the response, particularly for newer reasoning models. Parameters that are only supported for reasoning models are noted below. For the current state of unsupported parameters in reasoning models, refer to the reasoning guide.

ParametersExpand Collapse

ChatCompletionCreateParams params

List<ChatCompletionMessageParam> messages

A list of messages comprising the conversation so far. Depending on the model you use, different message types (modalities) are supported, like text, images, and audio.

class ChatCompletionDeveloperMessageParam:

Developer-provided instructions that the model should follow, regardless of messages sent by the user. With o1 models and newer, developer messages replace the previous system messages.

Content content

The contents of the developer message.

Accepts one of the following:

String

List<ChatCompletionContentPartText>

String text

The text content.

JsonValue; type

The type of the content part.

JsonValue; role

The role of the messages author, in this case developer.

Optional<String> name

An optional name for the participant. Provides the model information to differentiate between participants of the same role.

class ChatCompletionSystemMessageParam:

Developer-provided instructions that the model should follow, regardless of messages sent by the user. With o1 models and newer, use developer messages for this purpose instead.

Content content

The contents of the system message.

Accepts one of the following:

String

List<ChatCompletionContentPartText>

String text

The text content.

JsonValue; type

The type of the content part.

JsonValue; role

The role of the messages author, in this case system.

Optional<String> name

An optional name for the participant. Provides the model information to differentiate between participants of the same role.

class ChatCompletionUserMessageParam:

Messages sent by an end user, containing prompts or additional context information.

Content content

The contents of the user message.

Accepts one of the following:

String

List<ChatCompletionContentPart>

Accepts one of the following:

class ChatCompletionContentPartText:

Learn about text inputs.

String text

The text content.

JsonValue; type

The type of the content part.

class ChatCompletionContentPartImage:

Learn about image inputs.

ImageUrl imageUrl

String url

Either a URL of the image or the base64 encoded image data.

formaturi

Optional<Detail> detail

Specifies the detail level of the image. Learn more in the Vision guide.

Accepts one of the following:

AUTO("auto")

LOW("low")

HIGH("high")

JsonValue; type

The type of the content part.

class ChatCompletionContentPartInputAudio:

Learn about audio inputs.

InputAudio inputAudio

String data

Base64 encoded audio data.

Format format

The format of the encoded audio data. Currently supports "wav" and "mp3".

Accepts one of the following:

WAV("wav")

MP3("mp3")

JsonValue; type

The type of the content part. Always input_audio.

File

FileObject file

Optional<String> fileData

The base64 encoded file data, used when passing the file to the model as a string.

Optional<String> fileId

The ID of an uploaded file to use as input.

Optional<String> filename

The name of the file, used when passing the file to the model as a string.

JsonValue; type

The type of the content part. Always file.

JsonValue; role

The role of the messages author, in this case user.

Optional<String> name

An optional name for the participant. Provides the model information to differentiate between participants of the same role.

class ChatCompletionAssistantMessageParam:

Messages sent by the model in response to user messages.

JsonValue; role

The role of the messages author, in this case assistant.

Optional<Audio> audio

Data about a previous audio response from the model. Learn more.

String id

Unique identifier for a previous audio response from the model.

Optional<Content> content

The contents of the assistant message. Required unless tool_calls or function_call is specified.

Accepts one of the following:

String

List<ChatCompletionRequestAssistantMessageContentPart>

Accepts one of the following:

class ChatCompletionContentPartText:

Learn about text inputs.

String text

The text content.

JsonValue; type

The type of the content part.

class ChatCompletionContentPartRefusal:

String refusal

The refusal message generated by the model.

JsonValue; type

The type of the content part.

DeprecatedOptional<FunctionCall> functionCall

Deprecated and replaced by tool_calls. The name and arguments of a function that should be called, as generated by the model.

String arguments

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.

String name

The name of the function to call.

Optional<String> name

An optional name for the participant. Provides the model information to differentiate between participants of the same role.

Optional<String> refusal

The refusal message by the assistant.

Optional<List<ChatCompletionMessageToolCall>> toolCalls

The tool calls generated by the model, such as function calls.

Accepts one of the following:

class ChatCompletionMessageFunctionToolCall:

A call to a function tool created by the model.

String id

The ID of the tool call.

Function function

The function that the model called.

String arguments

String name

The name of the function to call.

JsonValue; type

The type of the tool. Currently, only function is supported.

class ChatCompletionMessageCustomToolCall:

A call to a custom tool created by the model.

String id

The ID of the tool call.

Custom custom

The custom tool that the model called.

String input

The input for the custom tool call generated by the model.

String name

The name of the custom tool to call.

JsonValue; type

The type of the tool. Always custom.

class ChatCompletionToolMessageParam:

Content content

The contents of the tool message.

Accepts one of the following:

String

List<ChatCompletionContentPartText>

String text

The text content.

JsonValue; type

The type of the content part.

JsonValue; role

The role of the messages author, in this case tool.

String toolCallId

Tool call that this message is responding to.

class ChatCompletionFunctionMessageParam:

Optional<String> content

The contents of the function message.

String name

The name of the function to call.

JsonValue; role

The role of the messages author, in this case function.

ChatModel model

Model ID used to generate the response, like gpt-4o or o3. OpenAI offers a wide range of models with different capabilities, performance characteristics, and price points. Refer to the model guide to browse and compare available models.

GPT_5_2("gpt-5.2")

GPT_5_2_2025_12_11("gpt-5.2-2025-12-11")

GPT_5_2_CHAT_LATEST("gpt-5.2-chat-latest")

GPT_5_2_PRO("gpt-5.2-pro")

GPT_5_2_PRO_2025_12_11("gpt-5.2-pro-2025-12-11")

GPT_5_1("gpt-5.1")

GPT_5_1_2025_11_13("gpt-5.1-2025-11-13")

GPT_5_1_CODEX("gpt-5.1-codex")

GPT_5_1_MINI("gpt-5.1-mini")

GPT_5_1_CHAT_LATEST("gpt-5.1-chat-latest")

GPT_5("gpt-5")

GPT_5_MINI("gpt-5-mini")

GPT_5_NANO("gpt-5-nano")

GPT_5_2025_08_07("gpt-5-2025-08-07")

GPT_5_MINI_2025_08_07("gpt-5-mini-2025-08-07")

GPT_5_NANO_2025_08_07("gpt-5-nano-2025-08-07")

GPT_5_CHAT_LATEST("gpt-5-chat-latest")

GPT_4_1("gpt-4.1")

GPT_4_1_MINI("gpt-4.1-mini")

GPT_4_1_NANO("gpt-4.1-nano")

GPT_4_1_2025_04_14("gpt-4.1-2025-04-14")

GPT_4_1_MINI_2025_04_14("gpt-4.1-mini-2025-04-14")

GPT_4_1_NANO_2025_04_14("gpt-4.1-nano-2025-04-14")

O4_MINI("o4-mini")

O4_MINI_2025_04_16("o4-mini-2025-04-16")

O3("o3")

O3_2025_04_16("o3-2025-04-16")

O3_MINI("o3-mini")

O3_MINI_2025_01_31("o3-mini-2025-01-31")

O1("o1")

O1_2024_12_17("o1-2024-12-17")

O1_PREVIEW("o1-preview")

O1_PREVIEW_2024_09_12("o1-preview-2024-09-12")

O1_MINI("o1-mini")

O1_MINI_2024_09_12("o1-mini-2024-09-12")

GPT_4O("gpt-4o")

GPT_4O_2024_11_20("gpt-4o-2024-11-20")

GPT_4O_2024_08_06("gpt-4o-2024-08-06")

GPT_4O_2024_05_13("gpt-4o-2024-05-13")

GPT_4O_AUDIO_PREVIEW("gpt-4o-audio-preview")

GPT_4O_AUDIO_PREVIEW_2024_10_01("gpt-4o-audio-preview-2024-10-01")

GPT_4O_AUDIO_PREVIEW_2024_12_17("gpt-4o-audio-preview-2024-12-17")

GPT_4O_AUDIO_PREVIEW_2025_06_03("gpt-4o-audio-preview-2025-06-03")

GPT_4O_MINI_AUDIO_PREVIEW("gpt-4o-mini-audio-preview")

GPT_4O_MINI_AUDIO_PREVIEW_2024_12_17("gpt-4o-mini-audio-preview-2024-12-17")

GPT_4O_SEARCH_PREVIEW("gpt-4o-search-preview")

GPT_4O_MINI_SEARCH_PREVIEW("gpt-4o-mini-search-preview")

GPT_4O_SEARCH_PREVIEW_2025_03_11("gpt-4o-search-preview-2025-03-11")

GPT_4O_MINI_SEARCH_PREVIEW_2025_03_11("gpt-4o-mini-search-preview-2025-03-11")

CHATGPT_4O_LATEST("chatgpt-4o-latest")

CODEX_MINI_LATEST("codex-mini-latest")

GPT_4O_MINI("gpt-4o-mini")

GPT_4O_MINI_2024_07_18("gpt-4o-mini-2024-07-18")

GPT_4_TURBO("gpt-4-turbo")

GPT_4_TURBO_2024_04_09("gpt-4-turbo-2024-04-09")

GPT_4_0125_PREVIEW("gpt-4-0125-preview")

GPT_4_TURBO_PREVIEW("gpt-4-turbo-preview")

GPT_4_1106_PREVIEW("gpt-4-1106-preview")

GPT_4_VISION_PREVIEW("gpt-4-vision-preview")

GPT_4("gpt-4")

GPT_4_0314("gpt-4-0314")

GPT_4_0613("gpt-4-0613")

GPT_4_32K("gpt-4-32k")

GPT_4_32K_0314("gpt-4-32k-0314")

GPT_4_32K_0613("gpt-4-32k-0613")

GPT_3_5_TURBO("gpt-3.5-turbo")

GPT_3_5_TURBO_16K("gpt-3.5-turbo-16k")

GPT_3_5_TURBO_0301("gpt-3.5-turbo-0301")

GPT_3_5_TURBO_0613("gpt-3.5-turbo-0613")

GPT_3_5_TURBO_1106("gpt-3.5-turbo-1106")

GPT_3_5_TURBO_0125("gpt-3.5-turbo-0125")

GPT_3_5_TURBO_16K_0613("gpt-3.5-turbo-16k-0613")

Optional<ChatCompletionAudioParam> audio

Parameters for audio output. Required when audio output is requested with modalities: ["audio"]. Learn more.

Optional<Double> frequencyPenalty

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.

minimum-2

maximum2

DeprecatedOptional<FunctionCall> functionCall

Deprecated in favor of tool_choice.

Controls which (if any) function is called by the model.

none means the model will not call a function and instead generates a message.

auto means the model can pick between generating a message or calling a function.

Specifying a particular function via {"name": "my_function"} forces the model to call that function.

none is the default when no functions are present. auto is the default if functions are present.

enum FunctionCallMode:

none means the model will not call a function and instead generates a message. auto means the model can pick between generating a message or calling a function.

NONE("none")

AUTO("auto")

class ChatCompletionFunctionCallOption:

Specifying a particular function via {"name": "my_function"} forces the model to call that function.

String name

The name of the function to call.

DeprecatedOptional<List<Function>> functions

Deprecated in favor of tools.

A list of functions the model may generate JSON inputs for.

String name

The name of the function to be called. Must be a-z, A-Z, 0-9, or contain underscores and dashes, with a maximum length of 64.

Optional<String> description

A description of what the function does, used by the model to choose when and how to call the function.

Optional<FunctionParameters> parameters

The parameters the functions accepts, described as a JSON Schema object. See the guide for examples, and the JSON Schema reference for documentation about the format.

Omitting parameters defines a function with an empty parameter list.

Optional<LogitBias> logitBias

Modify the likelihood of specified tokens appearing in the completion.

Accepts a JSON object that maps tokens (specified by their token ID in the tokenizer) to an associated bias value from -100 to 100. Mathematically, the bias is added to the logits generated by the model prior to sampling. The exact effect will vary per model, but values between -1 and 1 should decrease or increase likelihood of selection; values like -100 or 100 should result in a ban or exclusive selection of the relevant token.

Optional<Boolean> logprobs

Whether to return log probabilities of the output tokens or not. If true, returns the log probabilities of each output token returned in the content of message.

Optional<Long> maxCompletionTokens

An upper bound for the number of tokens that can be generated for a completion, including visible output tokens and reasoning tokens.

DeprecatedOptional<Long> maxTokens

The maximum number of tokens that can be generated in the chat completion. This value can be used to control costs for text generated via API.

This value is now deprecated in favor of max_completion_tokens, and is not compatible with o-series models.

Optional<Metadata> metadata

Set of 16 key-value pairs that can be attached to an object. This can be useful for storing additional information about the object in a structured format, and querying for objects via API or the dashboard.

Keys are strings with a maximum length of 64 characters. Values are strings with a maximum length of 512 characters.

Optional<List<Modality>> modalities

Output types that you would like the model to generate. Most models are capable of generating text, which is the default:

["text"]

The gpt-4o-audio-preview model can also be used to generate audio. To request that this model generate both text and audio responses, you can use:

["text", "audio"]

TEXT("text")

AUDIO("audio")

Optional<Long> n

How many chat completion choices to generate for each input message. Note that you will be charged based on the number of generated tokens across all of the choices. Keep n as 1 to minimize costs.

minimum1

maximum128

Optional<Boolean> parallelToolCalls

Whether to enable parallel function calling during tool use.

Optional<ChatCompletionPredictionContent> prediction

Static predicted output content, such as the content of a text file that is being regenerated.

Optional<Double> presencePenalty

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.

minimum-2

maximum2

Optional<String> promptCacheKey

Used by OpenAI to cache responses for similar requests to optimize your cache hit rates. Replaces the user field. Learn more.

Optional<PromptCacheRetention> promptCacheRetention

The retention policy for the prompt cache. Set to 24h to enable extended prompt caching, which keeps cached prefixes active for longer, up to a maximum of 24 hours. Learn more.

IN_MEMORY("in-memory")

_24H("24h")

Optional<ReasoningEffort> reasoningEffort

Constrains effort on reasoning for reasoning models. Currently supported values are none, minimal, low, medium, high, and xhigh. Reducing reasoning effort can result in faster responses and fewer tokens used on reasoning in a response.

gpt-5.1 defaults to none, which does not perform reasoning. The supported reasoning values for gpt-5.1 are none, low, medium, and high. Tool calls are supported for all reasoning values in gpt-5.1.
All models before gpt-5.1 default to medium reasoning effort, and do not support none.
The gpt-5-pro model defaults to (and only supports) high reasoning effort.
xhigh is supported for all models after gpt-5.1-codex-max.

Optional<ResponseFormat> responseFormat

An object specifying the format that the model must output.

Setting to { "type": "json_schema", "json_schema": {...} } enables Structured Outputs which ensures the model will match your supplied JSON schema. Learn more in the Structured Outputs guide.

Setting to { "type": "json_object" } enables the older JSON mode, which ensures the message the model generates is valid JSON. Using json_schema is preferred for models that support it.

class ResponseFormatText:

Default response format. Used to generate text responses.

JsonValue; type

The type of response format being defined. Always text.

class ResponseFormatJsonSchema:

JSON Schema response format. Used to generate structured JSON responses. Learn more about Structured Outputs.

JsonSchema jsonSchema

Structured Outputs configuration options, including a JSON Schema.

String name

The name of the response format. Must be a-z, A-Z, 0-9, or contain underscores and dashes, with a maximum length of 64.

Optional<String> description

A description of what the response format is for, used by the model to determine how to respond in the format.

Optional<Schema> schema

The schema for the response format, described as a JSON Schema object. Learn how to build JSON schemas here.

Optional<Boolean> strict

Whether to enable strict schema adherence when generating the output. If set to true, the model will always follow the exact schema defined in the schema field. Only a subset of JSON Schema is supported when strict is true. To learn more, read the Structured Outputs guide.

JsonValue; type

The type of response format being defined. Always json_schema.

class ResponseFormatJsonObject:

JSON object response format. An older method of generating JSON responses. Using json_schema is recommended for models that support it. Note that the model will not generate JSON without a system or user message instructing it to do so.

JsonValue; type

The type of response format being defined. Always json_object.

Optional<String> safetyIdentifier

A stable identifier used to help detect users of your application that may be violating OpenAI's usage policies. The IDs should be a string that uniquely identifies each user. We recommend hashing their username or email address, in order to avoid sending us any identifying information. Learn more.

DeprecatedOptional<Long> seed

This feature is in Beta. If specified, our system will make a best effort to sample deterministically, such that repeated requests with the same seed and parameters should return the same result. Determinism is not guaranteed, and you should refer to the system_fingerprint response parameter to monitor changes in the backend.

minimum-9223372036854776000

maximum9223372036854776000

Optional<ServiceTier> serviceTier

Specifies the processing type used for serving the request.

If set to 'auto', then the request will be processed with the service tier configured in the Project settings. Unless otherwise configured, the Project will use 'default'.
If set to 'default', then the request will be processed with the standard pricing and performance for the selected model.
If set to 'flex' or 'priority', then the request will be processed with the corresponding service tier.
When not set, the default behavior is 'auto'.

When the service_tier parameter is set, the response body will include the service_tier value based on the processing mode actually used to serve the request. This response value may be different from the value set in the parameter.

AUTO("auto")

DEFAULT("default")

FLEX("flex")

SCALE("scale")

PRIORITY("priority")

Optional<Stop> stop

Not supported with latest reasoning models o3 and o4-mini.

Up to 4 sequences where the API will stop generating further tokens. The returned text will not contain the stop sequence.

String

List<String>

Optional<Boolean> store

Whether or not to store the output of this chat completion request for use in our model distillation or evals products.

Supports text and image inputs. Note: image inputs over 8MB will be dropped.

Optional<ChatCompletionStreamOptions> streamOptions

Options for streaming response. Only set this when you set stream: true.

Optional<Double> temperature

What sampling temperature to use, between 0 and 2. 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.

minimum0

maximum2

Optional<ChatCompletionToolChoiceOption> toolChoice

Controls which (if any) tool is called by the model. none means the model will not call any tool and instead generates a message. auto means the model can pick between generating a message or calling one or more tools. required means the model must call one or more tools. Specifying a particular tool via {"type": "function", "function": {"name": "my_function"}} forces the model to call that tool.

none is the default when no tools are present. auto is the default if tools are present.

Optional<List<ChatCompletionTool>> tools

A list of tools the model may call. You can provide either custom tools or function tools.

class ChatCompletionFunctionTool:

A function tool that can be used to generate a response.

FunctionDefinition function

String name

The name of the function to be called. Must be a-z, A-Z, 0-9, or contain underscores and dashes, with a maximum length of 64.

Optional<String> description

A description of what the function does, used by the model to choose when and how to call the function.

Optional<FunctionParameters> parameters

The parameters the functions accepts, described as a JSON Schema object. See the guide for examples, and the JSON Schema reference for documentation about the format.

Omitting parameters defines a function with an empty parameter list.

Optional<Boolean> strict

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. Learn more about Structured Outputs in the function calling guide.

JsonValue; type

The type of the tool. Currently, only function is supported.

class ChatCompletionCustomTool:

A custom tool that processes input using a specified format.

Custom custom

Properties of the custom tool.

String name

The name of the custom tool, used to identify it in tool calls.

Optional<String> description

Optional description of the custom tool, used to provide more context.

Optional<Format> format

The input format for the custom tool. Default is unconstrained text.

Accepts one of the following:

JsonValue;

JsonValue; type

Unconstrained text format. Always text.

class Grammar:

A grammar defined by the user.

InnerGrammar grammar

Your chosen grammar.

String definition

The grammar definition.

Syntax syntax

The syntax of the grammar definition. One of lark or regex.

Accepts one of the following:

LARK("lark")

REGEX("regex")

JsonValue; type

Grammar format. Always grammar.

JsonValue; type

The type of the custom tool. Always custom.

Optional<Long> topLogprobs

An integer between 0 and 20 specifying the number of most likely tokens to return at each token position, each with an associated log probability. logprobs must be set to true if this parameter is used.

minimum0

maximum20

Optional<Double> topP

An alternative to sampling with temperature, called nucleus sampling, where the model considers the results of the tokens with top_p probability mass. So 0.1 means only the tokens comprising the top 10% probability mass are considered.

We generally recommend altering this or temperature but not both.

minimum0

maximum1

DeprecatedOptional<String> user

This field is being replaced by safety_identifier and prompt_cache_key. Use prompt_cache_key instead to maintain caching optimizations. A stable identifier for your end-users. Used to boost cache hit rates by better bucketing similar requests and to help OpenAI detect and prevent abuse. Learn more.

Optional<Verbosity> verbosity

Constrains the verbosity of the model's response. Lower values will result in more concise responses, while higher values will result in more verbose responses. Currently supported values are low, medium, and high.

LOW("low")

MEDIUM("medium")

HIGH("high")

Optional<WebSearchOptions> webSearchOptions

This tool searches the web for relevant results to use in a response. Learn more about the web search tool.

Optional<SearchContextSize> searchContextSize

High level guidance for the amount of context window space to use for the search. One of low, medium, or high. medium is the default.

Accepts one of the following:

LOW("low")

MEDIUM("medium")

HIGH("high")

Optional<UserLocation> userLocation

Approximate location parameters for the search.

Approximate approximate

Approximate location parameters for the search.

Optional<String> city

Free text input for the city of the user, e.g. San Francisco.

Optional<String> country

The two-letter ISO country code of the user, e.g. US.

Optional<String> region

Free text input for the region of the user, e.g. California.

Optional<String> timezone

The IANA timezone of the user, e.g. America/Los_Angeles.

JsonValue; type

The type of location approximation. Always approximate.

ReturnsExpand Collapse

class ChatCompletion:

Represents a chat completion response returned by model, based on the provided input.

String id

A unique identifier for the chat completion.

List<Choice> choices

A list of chat completion choices. Can be more than one if n is greater than 1.

FinishReason finishReason

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, content_filter if content was omitted due to a flag from our content filters, tool_calls if the model called a tool, or function_call (deprecated) if the model called a function.

Accepts one of the following:

STOP("stop")

LENGTH("length")

TOOL_CALLS("tool_calls")

CONTENT_FILTER("content_filter")

FUNCTION_CALL("function_call")

long index

The index of the choice in the list of choices.

Optional<Logprobs> logprobs

Log probability information for the choice.

Optional<List<ChatCompletionTokenLogprob>> content

A list of message content tokens with log probability information.

String token

The token.

Optional<List<Long>> bytes

A list of integers representing the UTF-8 bytes representation of the token. Useful in instances where characters are represented by multiple tokens and their byte representations must be combined to generate the correct text representation. Can be null if there is no bytes representation for the token.

double logprob

The log probability of this token, if it is within the top 20 most likely tokens. Otherwise, the value -9999.0 is used to signify that the token is very unlikely.

List<TopLogprob> topLogprobs

List of the most likely tokens and their log probability, at this token position. In rare cases, there may be fewer than the number of requested top_logprobs returned.

String token

The token.

Optional<List<Long>> bytes

double logprob

The log probability of this token, if it is within the top 20 most likely tokens. Otherwise, the value -9999.0 is used to signify that the token is very unlikely.

Optional<List<ChatCompletionTokenLogprob>> refusal

A list of message refusal tokens with log probability information.

String token

The token.

Optional<List<Long>> bytes

double logprob

The log probability of this token, if it is within the top 20 most likely tokens. Otherwise, the value -9999.0 is used to signify that the token is very unlikely.

List<TopLogprob> topLogprobs

List of the most likely tokens and their log probability, at this token position. In rare cases, there may be fewer than the number of requested top_logprobs returned.

String token

The token.

Optional<List<Long>> bytes

double logprob

The log probability of this token, if it is within the top 20 most likely tokens. Otherwise, the value -9999.0 is used to signify that the token is very unlikely.

ChatCompletionMessage message

A chat completion message generated by the model.

Optional<String> content

The contents of the message.

Optional<String> refusal

The refusal message generated by the model.

JsonValue; role

The role of the author of this message.

Optional<List<Annotation>> annotations

Annotations for the message, when applicable, as when using the web search tool.

JsonValue; type

The type of the URL citation. Always url_citation.

UrlCitation urlCitation

A URL citation when using web search.

long endIndex

The index of the last character of the URL citation in the message.

long startIndex

The index of the first character of the URL citation in the message.

String title

The title of the web resource.

String url

The URL of the web resource.

Optional<ChatCompletionAudio> audio

If the audio output modality is requested, this object contains data about the audio response from the model. Learn more.

String id

Unique identifier for this audio response.

String data

Base64 encoded audio bytes generated by the model, in the format specified in the request.

long expiresAt

The Unix timestamp (in seconds) for when this audio response will no longer be accessible on the server for use in multi-turn conversations.

String transcript

Transcript of the audio generated by the model.

DeprecatedOptional<FunctionCall> functionCall

Deprecated and replaced by tool_calls. The name and arguments of a function that should be called, as generated by the model.

String arguments

String name

The name of the function to call.

Optional<List<ChatCompletionMessageToolCall>> toolCalls

The tool calls generated by the model, such as function calls.

Accepts one of the following:

class ChatCompletionMessageFunctionToolCall:

A call to a function tool created by the model.

String id

The ID of the tool call.

Function function

The function that the model called.

String arguments

String name

The name of the function to call.

JsonValue; type

The type of the tool. Currently, only function is supported.

class ChatCompletionMessageCustomToolCall:

A call to a custom tool created by the model.

String id

The ID of the tool call.

Custom custom

The custom tool that the model called.

String input

The input for the custom tool call generated by the model.

String name

The name of the custom tool to call.

JsonValue; type

The type of the tool. Always custom.

long created

The Unix timestamp (in seconds) of when the chat completion was created.

String model

The model used for the chat completion.

JsonValue; object_

The object type, which is always chat.completion.

Optional<ServiceTier> serviceTier

Specifies the processing type used for serving the request.

If set to 'auto', then the request will be processed with the service tier configured in the Project settings. Unless otherwise configured, the Project will use 'default'.
If set to 'default', then the request will be processed with the standard pricing and performance for the selected model.
If set to 'flex' or 'priority', then the request will be processed with the corresponding service tier.
When not set, the default behavior is 'auto'.

Accepts one of the following:

AUTO("auto")

DEFAULT("default")

FLEX("flex")

SCALE("scale")

PRIORITY("priority")

DeprecatedOptional<String> systemFingerprint

This fingerprint represents the backend configuration that the model runs with.

Can be used in conjunction with the seed request parameter to understand when backend changes have been made that might impact determinism.

Optional<CompletionUsage> usage

Usage statistics for the completion request.

long completionTokens

Number of tokens in the generated completion.

long promptTokens

Number of tokens in the prompt.

long totalTokens

Total number of tokens used in the request (prompt + completion).

Optional<CompletionTokensDetails> completionTokensDetails

Breakdown of tokens used in a completion.

Optional<Long> acceptedPredictionTokens

When using Predicted Outputs, the number of tokens in the prediction that appeared in the completion.

Optional<Long> audioTokens

Audio input tokens generated by the model.

Optional<Long> reasoningTokens

Tokens generated by the model for reasoning.

Optional<Long> rejectedPredictionTokens

When using Predicted Outputs, the number of tokens in the prediction that did not appear in the completion. However, like reasoning tokens, these tokens are still counted in the total completion tokens for purposes of billing, output, and context window limits.

Optional<PromptTokensDetails> promptTokensDetails

Breakdown of tokens used in the prompt.

Optional<Long> audioTokens

Audio input tokens present in the prompt.

Optional<Long> cachedTokens

Cached tokens present in the prompt.

class ChatCompletionChunk:

Represents a streamed chunk of a chat completion response returned by the model, based on the provided input. Learn more.

String id

A unique identifier for the chat completion. Each chunk has the same ID.

List<Choice> choices

A list of chat completion choices. Can contain more than one elements if n is greater than 1. Can also be empty for the last chunk if you set stream_options: {"include_usage": true}.

Delta delta

A chat completion delta generated by streamed model responses.

Optional<String> content

The contents of the chunk message.

DeprecatedOptional<FunctionCall> functionCall

Deprecated and replaced by tool_calls. The name and arguments of a function that should be called, as generated by the model.

Optional<String> arguments

Optional<String> name

The name of the function to call.

Optional<String> refusal

The refusal message generated by the model.

Optional<Role> role

The role of the author of this message.

Accepts one of the following:

DEVELOPER("developer")

SYSTEM("system")

USER("user")

ASSISTANT("assistant")

TOOL("tool")

Optional<List<ToolCall>> toolCalls

long index

Optional<String> id

The ID of the tool call.

Optional<Function> function

Optional<String> arguments

Optional<String> name

The name of the function to call.

Optional<Type> type

The type of the tool. Currently, only function is supported.

Optional<FinishReason> finishReason

Accepts one of the following:

STOP("stop")

LENGTH("length")

TOOL_CALLS("tool_calls")

CONTENT_FILTER("content_filter")

FUNCTION_CALL("function_call")

long index

The index of the choice in the list of choices.

Optional<Logprobs> logprobs

Log probability information for the choice.

Optional<List<ChatCompletionTokenLogprob>> content

A list of message content tokens with log probability information.

String token

The token.

Optional<List<Long>> bytes

double logprob

The log probability of this token, if it is within the top 20 most likely tokens. Otherwise, the value -9999.0 is used to signify that the token is very unlikely.

List<TopLogprob> topLogprobs

List of the most likely tokens and their log probability, at this token position. In rare cases, there may be fewer than the number of requested top_logprobs returned.

String token

The token.

Optional<List<Long>> bytes

double logprob

The log probability of this token, if it is within the top 20 most likely tokens. Otherwise, the value -9999.0 is used to signify that the token is very unlikely.

Optional<List<ChatCompletionTokenLogprob>> refusal

A list of message refusal tokens with log probability information.

String token

The token.

Optional<List<Long>> bytes

double logprob

The log probability of this token, if it is within the top 20 most likely tokens. Otherwise, the value -9999.0 is used to signify that the token is very unlikely.

List<TopLogprob> topLogprobs

List of the most likely tokens and their log probability, at this token position. In rare cases, there may be fewer than the number of requested top_logprobs returned.

String token

The token.

Optional<List<Long>> bytes

double logprob

The log probability of this token, if it is within the top 20 most likely tokens. Otherwise, the value -9999.0 is used to signify that the token is very unlikely.

long created

The Unix timestamp (in seconds) of when the chat completion was created. Each chunk has the same timestamp.

String model

The model to generate the completion.

JsonValue; object_

The object type, which is always chat.completion.chunk.

Optional<ServiceTier> serviceTier

Specifies the processing type used for serving the request.

If set to 'auto', then the request will be processed with the service tier configured in the Project settings. Unless otherwise configured, the Project will use 'default'.
If set to 'default', then the request will be processed with the standard pricing and performance for the selected model.
If set to 'flex' or 'priority', then the request will be processed with the corresponding service tier.
When not set, the default behavior is 'auto'.

Accepts one of the following:

AUTO("auto")

DEFAULT("default")

FLEX("flex")

SCALE("scale")

PRIORITY("priority")

DeprecatedOptional<String> systemFingerprint

This fingerprint represents the backend configuration that the model runs with. Can be used in conjunction with the seed request parameter to understand when backend changes have been made that might impact determinism.

Optional<CompletionUsage> usage

An optional field that will only be present when you set stream_options: {"include_usage": true} in your request. When present, it contains a null value except for the last chunk which contains the token usage statistics for the entire request.

NOTE: If the stream is interrupted or cancelled, you may not receive the final usage chunk which contains the total token usage for the request.

long completionTokens

Number of tokens in the generated completion.

long promptTokens

Number of tokens in the prompt.

long totalTokens

Total number of tokens used in the request (prompt + completion).

Optional<CompletionTokensDetails> completionTokensDetails

Breakdown of tokens used in a completion.

Optional<Long> acceptedPredictionTokens

When using Predicted Outputs, the number of tokens in the prediction that appeared in the completion.

Optional<Long> audioTokens

Audio input tokens generated by the model.

Optional<Long> reasoningTokens

Tokens generated by the model for reasoning.

Optional<Long> rejectedPredictionTokens

Optional<PromptTokensDetails> promptTokensDetails

Breakdown of tokens used in the prompt.

Optional<Long> audioTokens

Audio input tokens present in the prompt.

Optional<Long> cachedTokens

Cached tokens present in the prompt.