diff --git a/src/chatgpt-api.ts b/src/chatgpt-api.ts
index b45f4a07..0d5cea86 100644
--- a/src/chatgpt-api.ts
+++ b/src/chatgpt-api.ts
@@ -145,7 +145,7 @@ export class ChatGPTAPI {
       onProgress,
       stream = onProgress ? true : false,
       completionParams,
-      conversationId = ''
+      conversationId
     } = opts
 
     let { abortSignal } = opts
@@ -159,9 +159,9 @@ export class ChatGPTAPI {
     const message: types.ChatMessage = {
       role: 'user',
       id: messageId,
+      conversationId,
       parentMessageId,
-      text,
-      conversationId
+      text
     }
 
     const latestQuestion = message
@@ -174,9 +174,9 @@ export class ChatGPTAPI {
     const result: types.ChatMessage = {
       role: 'assistant',
       id: uuidv4(),
+      conversationId,
       parentMessageId: messageId,
-      text: '',
-      conversationId
+      text: ''
     }
 
     const responseP = new Promise<types.ChatMessage>(
diff --git a/src/types.ts b/src/types.ts
index 5c44dcc1..16b64f21 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -74,7 +74,8 @@ export interface ChatMessage {
 
   // relevant for both ChatGPTAPI and ChatGPTUnofficialProxyAPI
   parentMessageId?: string
-  // only relevant for ChatGPTUnofficialProxyAPI
+
+  // only relevant for ChatGPTUnofficialProxyAPI (optional for ChatGPTAPI)
   conversationId?: string
 }