OpenAI · Schema

OpenAI Chat Completion

A chat completion response object returned by the OpenAI Chat Completions API. Represents a model-generated message in response to a conversation comprising a list of messages.

AIArtificial IntelligenceLarge Language ModelsT1

Properties

Name Type Description
id string A unique identifier for the chat completion. Prefixed with chatcmpl-.
object string The object type, which is always chat.completion.
created integer The Unix timestamp (in seconds) of when the chat completion was created.
model string The model used for the chat completion (e.g., gpt-5, gpt-4.1, o4-mini).
system_fingerprint stringnull 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
service_tier stringnull The service tier used for processing the request. This field is only included if the service_tier parameter is specified in the request.
choices array A list of chat completion choices. Can be more than one if n is greater than 1.
usage object
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