Create a chat completion

Generate a chat completion from one of the available models. Mixlayer’s API is OpenAI-compatible, so existing OpenAI client libraries work without modification — see Client Libraries for examples.

Set reasoning_effort to default, none, minimal, low, medium, high, xhigh, or max, or omit it for the model default. Some models also support numeric reasoning effort. Check the model’s Mixlayer documentation page for supported values and ranges. Models reject unsupported efforts; see Reasoning for model-specific mappings and legacy boolean controls.

Set stream to true to receive JSON chunks as server-sent events; the stream ends with data: [DONE].

Authentication

AuthorizationBearer

Mixlayer API key or console user session supplied as a Bearer token.

Request

Chat completion parameters

messageslist of objectsRequired

Message objects in turn order. Each message has a role and content.

modelstringRequired

Model identifier.

web_search_optionsobject or nullOptional

Chat Completions request shape for hosted web search.

frequency_penaltyfloat or nullOptional

Penalizes tokens proportional to how often they have appeared. Positive values reduce repetition.

max_completion_tokensinteger or nullOptional>=0

Maximum tokens to generate. Takes precedence over max_tokens.

max_tokensinteger or nullOptional>=0

Legacy alias for max_completion_tokens.

metadataanyOptional

Developer-supplied metadata stored with the response when store is true.

parallel_tool_callsboolean or nullOptional

Whether the model may emit multiple tool calls in one generation leg.

presence_penaltyfloat or nullOptional

Penalizes tokens that have appeared at all. Positive values encourage topical novelty.

reasoningboolean or object or nullOptional

Reasoning configuration accepting the legacy boolean and object forms.

reasoning_effortstring or integer or nullOptional

Reasoning effort: default, none, minimal, low, medium, high, xhigh, or max. Some models also support numeric reasoning effort. Check the model’s Mixlayer documentation page for supported values and ranges. Omit for the model default. See Reasoning for model-specific mappings and unsupported values.

repetition_penaltyfloat or nullOptional

Multiplicative penalty on tokens already in the context. 1.0 applies no penalty.

response_formatobject or nullOptional

seedlong or nullOptional>=0

Best-effort deterministic sampling seed.

stoplist of strings or nullOptional

Sequences that halt generation. The stop sequence is not included in the output.

storebooleanOptionalDefaults to false

Persist the completed request and response for later use.

streambooleanOptionalDefaults to false

If true, stream the response as Server-Sent Events. Defaults to false.

stream_optionsobject or nullOptional

temperaturefloat or nullOptional

Controls randomness. Lower values make output more deterministic; higher values make it more diverse.

thinkingboolean or nullOptional

Legacy boolean reasoning switch.

toolslist of objects or nullOptional

Function tools the model may call.

top_kinteger or nullOptional

Only consider the top-k most likely tokens at each step.

top_pfloat or nullOptional

Only consider tokens whose cumulative probability is below this value.

Response

A complete response or a stream of completion chunks, selected by the request’s stream field

choiceslist of objects

Generated completion choices.

createdlong>=0

Unix timestamp when the completion was created.

idstring

Unique identifier for the chat completion.

modelstring

Model used to generate the completion.

objectenum

Object type, always chat.completion.

Allowed values:

usageobject

Token usage for the request.

Errors

400

Bad Request Error

401

Unauthorized Error

402

Payment Required Error

403

Forbidden Error

429

Too Many Requests Error

500

Internal Server Error