diff --git a/src/models/carrier_account.js b/src/models/carrier_account.ts
similarity index 50%
rename from src/models/carrier_account.js
rename to src/models/carrier_account.ts
index 05163014d..83a7d9523 100644
--- a/src/models/carrier_account.js
+++ b/src/models/carrier_account.ts
@@ -6,12 +6,12 @@ import EasyPostObject from './easypost_object';
  * @extends EasyPostObject
  */
 export default class CarrierAccount extends EasyPostObject {
-  static billing_type;
-  static clone;
-  static credentials;
-  static description;
-  static fields;
-  static readable;
-  static reference;
-  static test_credentials;
+  declare billing_type?: string | null;
+  declare clone?: boolean | null;
+  declare credentials?: object | null;
+  declare description?: string | null;
+  declare fields?: Record<string, unknown> | null;
+  declare readable?: string | null;
+  declare reference?: string | null;
+  declare test_credentials?: object | null;
 }
diff --git a/src/models/carrier_type.js b/src/models/carrier_type.ts
similarity index 78%
rename from src/models/carrier_type.js
rename to src/models/carrier_type.ts
index 74cb573c4..99769987b 100644
--- a/src/models/carrier_type.js
+++ b/src/models/carrier_type.ts
@@ -6,6 +6,6 @@ import EasyPostObject from './easypost_object';
  * @extends EasyPostObject
  */
 export default class CarrierType extends EasyPostObject {
-  static fields;
-  static type;
+  declare fields?: Record<string, unknown> | null;
+  declare type?: string | null;
 }