Input Params

Common Params

LiteLLM accepts and translates the OpenAI Chat Completion params across all providers.

Usage

import litellm

# set env variables
os.environ["OPENAI_API_KEY"] = "your-openai-key"

## SET MAX TOKENS - via completion() 
response = litellm.completion(
            model="gpt-5.6-luna",
            messages=[{ "content": "Hello, how are you?","role": "user"}],
            max_tokens=10
        )

print(response)

Translated OpenAI params

Use this function to get an up-to-date list of supported openai params for any model + provider.

from litellm import get_supported_openai_params

response = get_supported_openai_params(model="anthropic.claude-sonnet-5", custom_llm_provider="bedrock")

print(response) # ["max_tokens", "tools", "tool_choice", "stream"]

This table is the output of litellm.get_supported_openai_params() for the model shown in each row. Support is model dependent within a provider (for example Bedrock Llama models do not list tools or tool_choice), so call the function for the exact model you use

stream_options, extra_headers and max_retries are not checked against this list and are accepted for every provider, and stream_options={"include_usage": True} returns usage on the final chunk for every provider

Provider	Model checked	temperature	max_completion_tokens	max_tokens	top_p	stream	stop	n	presence_penalty	frequency_penalty	functions	function_call	logit_bias	user	response_format	seed	tools	tool_choice	logprobs	top_logprobs
Anthropic	`claude-sonnet-4-5-20250929`	✅	✅	✅	✅	✅	✅							✅	✅		✅	✅
OpenAI	`gpt-4o`	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅
Azure OpenAI	`gpt-4o`	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅
xAI	`grok-3`	✅	✅	✅	✅	✅	✅	✅	✅	✅			✅	✅	✅	✅	✅	✅	✅	✅
Replicate	`meta/llama-2-70b-chat`	✅		✅	✅	✅	✅				✅	✅				✅	✅	✅
Anyscale	`meta-llama/Llama-2-70b-chat-hf`	✅		✅	✅	✅	✅		✅	✅
Cohere	`command-r`	✅	✅	✅	✅	✅	✅	✅	✅	✅						✅	✅	✅
Huggingface	`meta-llama/Llama-3.1-8B-Instruct`	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅		✅	✅	✅	✅	✅	✅
Openrouter	`openai/gpt-4o`	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅		✅	✅	✅	✅	✅	✅
AI21	`jamba-1.5-large`	✅	✅	✅		✅	✅	✅							✅	✅	✅	✅
VertexAI	`gemini-2.5-flash`	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅				✅	✅	✅	✅	✅	✅
Bedrock	`anthropic.claude-3-5-sonnet-20240620-v1:0`	✅	✅	✅	✅	✅	✅								✅		✅	✅
Sagemaker	`jumpstart-dft-meta-textgeneration-llama-2-7b`	✅	✅	✅	✅	✅	✅	✅
TogetherAI	`meta-llama/Llama-3-70b-chat-hf`	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅		✅	✅	✅	✅	✅	✅
Sambanova	`Meta-Llama-3.1-8B-Instruct`	✅	✅	✅	✅	✅	✅								✅
AlephAlpha	`luminous-base`	✅		✅	✅	✅	✅	✅	✅	✅
NLP Cloud	`dolphin`	✅		✅	✅	✅	✅	✅	✅	✅
Petals	`petals-team/StableBeluga2`	✅		✅	✅	✅
Ollama	`llama3`	✅	✅	✅	✅	✅	✅			✅					✅	✅
Databricks	`databricks-dbrx-instruct`	✅	✅	✅	✅	✅	✅	✅							✅		✅	✅
ClarifAI	`openai.chat-completion.gpt-4o`	✅	✅	✅	✅	✅			✅	✅					✅		✅	✅
Github	`gpt-4o`	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅
Novita AI	`meta-llama/llama-3-8b-instruct`	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅		✅	✅	✅	✅	✅	✅
Bytez	`google/gemma-3-1b-it`	✅	✅	✅	✅	✅		✅
OVHCloud AI Endpoints	`Meta-Llama-3_3-70B-Instruct`	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅	✅		✅	✅	✅	✅	✅	✅

note

By default, LiteLLM raises an exception if the openai param being passed in isn't supported.

To drop the param instead, set litellm.drop_params = True or completion(..drop_params=True).

This ONLY DROPS UNSUPPORTED OPENAI PARAMS.

LiteLLM assumes any non-openai param is provider specific and passes it in as a kwarg in the request body

Input Params

def completion(
    model: str,
    messages: list = [],
    timeout: float | str | httpx.Timeout | None = None,
    temperature: float | None = None,
    top_p: float | None = None,
    n: int | None = None,
    stream: bool | None = None,
    stream_options: dict | None = None,
    stop=None,
    max_completion_tokens: int | None = None,
    max_tokens: int | None = None,
    modalities: list[ChatCompletionModality] | None = None,
    prediction: ChatCompletionPredictionContentParam | None = None,
    audio: ChatCompletionAudioParam | None = None,
    presence_penalty: float | None = None,
    frequency_penalty: float | None = None,
    logit_bias: dict | None = None,
    user: str | None = None,
    # openai v1.0+ new params
    reasoning_effort: Literal["none", "minimal", "low", "medium", "high", "xhigh", "max", "default"] | None = None,
    verbosity: Literal["low", "medium", "high"] | None = None,
    response_format: dict | type[BaseModel] | None = None,
    seed: int | None = None,
    tools: list | None = None,
    tool_choice: str | dict | None = None,
    logprobs: bool | None = None,
    top_logprobs: int | None = None,
    parallel_tool_calls: bool | None = None,
    web_search_options: OpenAIWebSearchOptions | None = None,
    include_server_side_tool_invocations: bool | None = None,
    deployment_id=None,
    extra_headers: dict | None = None,
    safety_identifier: str | None = None,
    service_tier: str | None = None,
    store: bool | None = None,
    prompt_cache_key: str | None = None,
    # soon to be deprecated params by OpenAI
    functions: list | None = None,
    function_call: str | None = None,
    # set api_base, api_version, api_key
    base_url: str | None = None,
    api_version: str | None = None,
    api_key: str | None = None,
    model_list: list | None = None,  # pass in a list of api_base,keys, etc.
    # Optional liteLLM function params
    thinking: AnthropicThinkingParam | None = None,
    # Session management
    shared_session: Optional["ClientSession"] = None,
    # Per-request JSON schema validation (overrides litellm.enable_json_schema_validation)
    enable_json_schema_validation: bool | None = None,
    **kwargs,
) -> ModelResponse | CustomStreamWrapper:
    ...

Required Fields

model: string - ID of the model to use. Refer to the model endpoint compatibility table for details on which models work with the Chat API.
messages: array - A list of messages comprising the conversation so far.

Properties of `messages`

Note - Each message in the array contains the following properties:

role: string - The role of the message's author. Roles can be: system, user, assistant, function or tool.
content: string or list[dict] or null - The contents of the message. It is required for all messages, but may be null for assistant messages with function calls.
name: string (optional) - The name of the author of the message. It is required if the role is "function". The name should match the name of the function represented in the content. It can contain characters (a-z, A-Z, 0-9), and underscores, with a maximum length of 64 characters.
function_call: object (optional) - The name and arguments of a function that should be called, as generated by the model.
tool_call_id: str (optional) - Tool call that this message is responding to.

See All Message Values

Content Types

content can be a string (text only) or a list of content blocks (multimodal):

Type	Description	Docs
`text`	Text content	Type Definition
`image_url`	Images	Vision
`input_audio`	Audio input	Audio
`video_url`	Video input	Type Definition
`file`	Files	Document Understanding
`document`	Documents/PDFs	Document Understanding

Examples:

# Text
messages=[{"role": "user", "content": [{"type": "text", "text": "Hello!"}]}]

# Image
messages=[{"role": "user", "content": [{"type": "image_url", "image_url": {"url": "https://example.com/image.jpg"}}]}]

# Audio
messages=[{"role": "user", "content": [{"type": "input_audio", "input_audio": {"data": "<base64>", "format": "wav"}}]}]

# Video
messages=[{"role": "user", "content": [{"type": "video_url", "video_url": {"url": "https://example.com/video.mp4"}}]}]

# File
messages=[{"role": "user", "content": [{"type": "file", "file": {"file_id": "https://example.com/doc.pdf"}}]}]

# Document
messages=[{"role": "user", "content": [{"type": "document", "source": {"type": "text", "media_type": "application/pdf", "data": "<base64>"}}]}]

# Combining multiple types (multimodal)
messages=[{"role": "user", "content": [
    {"type": "text", "text": "Generate a product description based on this image"},
    {"type": "image_url", "image_url": {"url": "https://example.com/image.jpg"}}
]}]

Optional Fields

temperature: number or null (optional) - The sampling temperature to be used, between 0 and 2. Higher values like 0.8 produce more random outputs, while lower values like 0.2 make outputs more focused and deterministic.
top_p: number or null (optional) - An alternative to sampling with temperature. It instructs the model to consider the results of the tokens with top_p probability. For example, 0.1 means only the tokens comprising the top 10% probability mass are considered.
n: integer or null (optional) - The number of chat completion choices to generate for each input message.
stream: boolean or null (optional) - If set to true, it sends partial message deltas. Tokens will be sent as they become available, with the stream terminated by a [DONE] message.
stream_options dict or null (optional) - Options for streaming response. Only set this when you set stream: true
- include_usage boolean (optional) - If set, an additional chunk will be streamed before the data: [DONE] message. The usage field on this chunk shows the token usage statistics for the entire request, and the choices field will always be an empty array. All other chunks will also include a usage field, but with a null value.
stop: string/ array/ null (optional) - Up to 4 sequences where the API will stop generating further tokens.

Note: OpenAI supports a maximum of 4 stop sequences. If you provide more than 4, LiteLLM will automatically truncate the list to the first 4 elements. To disable this automatic truncation, set litellm.disable_stop_sequence_limit = True.
max_completion_tokens: integer (optional) - An upper bound for the number of tokens that can be generated for a completion, including visible output tokens and reasoning tokens.
max_tokens: integer (optional) - The maximum number of tokens to generate in the chat completion.
presence_penalty: number or null (optional) - It is used to penalize new tokens based on their existence in the text so far.
response_format: dict or Pydantic model class (optional) - Specifies the response format. Pass a Pydantic model class to request schema-based output; see JSON mode and structured outputs.
- Setting to { "type": "json_object" } enables JSON mode, which guarantees the message the model generates is valid JSON.
- Important: when using JSON mode, you must also instruct the model to produce JSON yourself via a system or user message. Without this, the model may generate an unending stream of whitespace until the generation reaches the token limit, resulting in a long-running and seemingly "stuck" request. Also note that the message content may be partially cut off if finish_reason="length", which indicates the generation exceeded max_tokens or the conversation exceeded the max context length.
seed: integer or null (optional) - 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.
tools: array (optional) - A list of tools the model may call. Use this to provide a list of functions the model may generate JSON inputs for.
- type: string - The type of the tool. You can set this to "function" or "mcp" (matching the /responses schema) to call LiteLLM-registered MCP servers directly from /chat/completions.
- function: object - Required for function tools.
tool_choice: string or dict (optional) - Controls which tool, if any, the model calls. Use none or auto, or provide a dict naming a specific tool.
- none is the default when no functions are present. auto is the default if functions are present.
parallel_tool_calls: boolean (optional) - Whether to enable parallel function calling during tool use. OpenAI default is true.
frequency_penalty: number or null (optional) - It is used to penalize new tokens based on their frequency in the text so far.
logit_bias: map (optional) - Used to modify the probability of specific tokens appearing in the completion.
user: string (optional) - A unique identifier representing your end-user. This can help OpenAI to monitor and detect abuse.
timeout: float, string, httpx.Timeout or null (optional) - Request timeout in seconds. A string can contain the numeric timeout value; use httpx.Timeout to configure timeout phases separately.
logprobs: * bool (optional)* - 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
top_logprobs: int (optional) - An integer between 0 and 5 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.
safety_identifier: string (optional) - A unique identifier for tracking and managing safety-related requests. This parameter helps with safety monitoring and compliance tracking.
headers: dict (optional) - A dictionary of headers to be sent with the request.
extra_headers: dict (optional) - Alternative to headers, used to send extra headers in LLM API request.
reasoning_effort: string or null (optional) - Sets the reasoning effort for supported models. Values are none, minimal, low, medium, high, xhigh, max and default. See reasoning content.
verbosity: string or null (optional) - Sets the output verbosity to low, medium or high for supported OpenAI GPT-5 family models.
thinking: object or null (optional) - Anthropic-style thinking configuration. See reasoning content.
modalities: array or null (optional) - Requested output modalities, such as text and audio. See audio.
audio: object or null (optional) - Audio output settings, such as voice and format. See audio.
prediction: object or null (optional) - Expected output content that can reduce latency when much of the response is known in advance. See predicted outputs.
web_search_options: object or null (optional) - Options for supported built-in web search models and endpoints, such as search context size. See web search.
include_server_side_tool_invocations: boolean or null (optional) - For supported Gemini/Vertex requests, sets toolConfig.includeServerSideToolInvocations.
service_tier: string or null (optional) - Requests a processing service tier where the model supports it.
store: boolean or null (optional) - Controls whether the provider stores the response where supported.
prompt_cache_key: string or null (optional) - OpenAI prompt-cache routing hint for requests with shared prefixes. See prompt caching.
shared_session: aiohttp ClientSession or null (optional) - Reuses a session across asynchronous API calls. See shared sessions.
enable_json_schema_validation: boolean or null (optional) - Enables or disables per-request validation of generated JSON against the requested schema, overriding the global setting. See JSON mode and structured outputs.
api_key: string or null (optional) - Provider API key to use for this request.
base_url: string or null (optional) - Provider API base URL. Alias for api_base.
model_list: list or null (optional) - Model deployment configurations used to select and call deployments matching model.

Deprecated Params

functions: array - A list of functions that the model may use to generate JSON inputs. Each function should have the following properties:
- name: string - The name of the function to be called. It should contain a-z, A-Z, 0-9, underscores and dashes, with a maximum length of 64 characters.
- description: string (optional) - A description explaining what the function does. It helps the model to decide when and how to call the function.
- parameters: object - The parameters that the function accepts, described as a JSON Schema object.
function_call: string or object (optional) - Controls how the model responds to function calls.

litellm-specific params

api_base: string (optional) - The api endpoint you want to call the model with
api_version: string (optional) - (Azure-specific) the api version for the call
num_retries: int (optional) - The number of times to retry the API call if an APIError, TimeoutError or ServiceUnavailableError occurs
context_window_fallback_dict: dict (optional) - A mapping of model to use if call fails due to context window error
fallbacks: list (optional) - A list of model names + params to be used, in case the initial call fails
metadata: dict (optional) - Any additional data you want to be logged when the call is made (sent to logging integrations, eg. promptlayer and accessible via custom callback function)
custom_llm_provider: string (optional) - Provider identifier to use when resolving the model and its API configuration
drop_params: boolean (optional) - Drops unsupported OpenAI parameters instead of raising an error. See drop unsupported params.
additional_drop_params: list of strings (optional) - OpenAI parameters to drop from the request. See drop unsupported params.
allowed_openai_params: list of strings (optional) - OpenAI parameters allowed through for this request. See drop unsupported params.
mock_response: string or response object (optional) - Returns a mock completion response without calling the model. See mock requests.
max_retries: integer (optional) - Maximum number of retries for the API call
ssl_verify: boolean or string (optional) - Enables or disables SSL verification, or sets a custom CA bundle path. See SSL security settings.
merge_reasoning_content_in_choices: boolean (optional) - For streaming responses, adds reasoning_content to content inside <think> tags for clients that expect reasoning in content
prompt_id: string (optional) - Managed prompt ID passed to prompt-management hooks. See prompt management.
prompt_variables: dict (optional) - Values used to fill managed prompt variables when prompt-management hooks are configured. See prompt management.
litellm_system_prompt: string (optional) - Prepends this prompt to the first system message, or adds a system message at the start if none exists
base_model: string (optional) - Underlying model name used for provider-specific model and parameter configuration. See fine-tuned models.
supports_system_message: boolean (optional) - Set to false when the model does not accept system-role messages; LiteLLM then remaps those messages
ensure_alternating_roles: boolean (optional) - Adds user or assistant continuation messages where needed to alternate conversation roles. See message sanitization.
user_continue_message: message object (optional) - Custom user message inserted when alternating roles require a user turn. See message sanitization.
assistant_continue_message: message object (optional) - Custom assistant message inserted when alternating roles require an assistant turn. See message sanitization.
cooldown_time: float (optional) - Cooldown duration in seconds before a failed routed deployment can be retried

CUSTOM MODEL COST

input_cost_per_token: float (optional) - The cost per input token for the completion call
output_cost_per_token: float (optional) - The cost per output token for the completion call
cost_per_second: float (optional) - Per-second rate used to calculate costs for models billed by duration
input_cost_per_second: float (optional) - Per-second input rate used to calculate costs for models billed by duration
output_cost_per_second: float (optional) - Per-second output rate used to calculate costs for models billed by duration

CUSTOM PROMPT TEMPLATE (See prompt formatting for more info)

initial_prompt_value: string (optional) - Initial string applied at the start of the input messages
roles: dict (optional) - Dictionary specifying how to format the prompt based on the role + message passed in via messages.
final_prompt_value: string (optional) - Final string applied at the end of the input messages
bos_token: string (optional) - Initial string applied at the start of a sequence
eos_token: string (optional) - Initial string applied at the end of a sequence
hf_model_name: string (optional) - [Sagemaker Only] The corresponding huggingface name of the model, used to pull the right chat template for the model.

Common Params​

Usage​

Translated OpenAI params​

Input Params​

Required Fields​

Properties of messages​

Content Types​

Optional Fields​

Deprecated Params​

litellm-specific params​

Common Params

Usage

Translated OpenAI params

Input Params

Required Fields

Properties of `messages`

Content Types

Optional Fields

Deprecated Params

litellm-specific params