diff --git a/chat.go b/chat.go
index d05fc8e..3208906 100644
--- a/chat.go
+++ b/chat.go
@@ -263,6 +263,7 @@ type ChatCompletionRequest struct {
 	// Metadata to store with the completion.
 	Metadata         map[string]string `json:"metadata,omitempty"`
 	IncludeReasoning *bool             `json:"include_reasoning,omitempty"`
+	ReasoningFormat  *string           `json:"reasoning_format,omitempty"`
 }
 
 type StreamOptions struct {