diff --git a/deno/rest/v10/webhook.ts b/deno/rest/v10/webhook.ts
index d77f7036..eaea4f9a 100644
--- a/deno/rest/v10/webhook.ts
+++ b/deno/rest/v10/webhook.ts
@@ -149,7 +149,7 @@ export type RESTPostAPIWebhookWithTokenJSONBody = AddUndefinedToPossiblyUndefine
 	 *
 	 * Available only if the webhook is in a forum channel and a thread is not specified in {@link RESTPostAPIWebhookWithTokenQuery.thread_id} query parameter
 	 */
-	thread_name: string;
+	thread_name?: string;
 }>;
 
 /**
diff --git a/deno/rest/v9/webhook.ts b/deno/rest/v9/webhook.ts
index 38c4dc6b..7005a254 100644
--- a/deno/rest/v9/webhook.ts
+++ b/deno/rest/v9/webhook.ts
@@ -149,7 +149,7 @@ export type RESTPostAPIWebhookWithTokenJSONBody = AddUndefinedToPossiblyUndefine
 	 *
 	 * Available only if the webhook is in a forum channel and a thread is not specified in {@link RESTPostAPIWebhookWithTokenQuery.thread_id} query parameter
 	 */
-	thread_name: string;
+	thread_name?: string;
 }>;
 
 /**
diff --git a/rest/v10/webhook.ts b/rest/v10/webhook.ts
index f60d29f1..bcd8adc6 100644
--- a/rest/v10/webhook.ts
+++ b/rest/v10/webhook.ts
@@ -149,7 +149,7 @@ export type RESTPostAPIWebhookWithTokenJSONBody = AddUndefinedToPossiblyUndefine
 	 *
 	 * Available only if the webhook is in a forum channel and a thread is not specified in {@link RESTPostAPIWebhookWithTokenQuery.thread_id} query parameter
 	 */
-	thread_name: string;
+	thread_name?: string;
 }>;
 
 /**
diff --git a/rest/v9/webhook.ts b/rest/v9/webhook.ts
index 8bfc39d6..d94c9a15 100644
--- a/rest/v9/webhook.ts
+++ b/rest/v9/webhook.ts
@@ -149,7 +149,7 @@ export type RESTPostAPIWebhookWithTokenJSONBody = AddUndefinedToPossiblyUndefine
 	 *
 	 * Available only if the webhook is in a forum channel and a thread is not specified in {@link RESTPostAPIWebhookWithTokenQuery.thread_id} query parameter
 	 */
-	thread_name: string;
+	thread_name?: string;
 }>;
 
 /**