diff --git a/api/src/main/java/com/theokanning/openai/completion/chat/ChatCompletionRequest.java b/api/src/main/java/com/theokanning/openai/completion/chat/ChatCompletionRequest.java
index e4479ff3..257a2d32 100644
--- a/api/src/main/java/com/theokanning/openai/completion/chat/ChatCompletionRequest.java
+++ b/api/src/main/java/com/theokanning/openai/completion/chat/ChatCompletionRequest.java
@@ -15,6 +15,12 @@
 @NoArgsConstructor
 public class ChatCompletionRequest {
 
+    /**
+     * Specify "json" to ensure the response content is valid json. You must also specify json in the chat instructions.
+     * See https://platform.openai.com/docs/guides/text-generation/json-mode
+     */
+    String format;
+    
     /**
      * ID of the model to use.
      */