diff --git a/src/types/auth.d.ts b/src/types/auth.d.ts
new file mode 100644
index 0000000..a42e2f6
--- /dev/null
+++ b/src/types/auth.d.ts
@@ -0,0 +1,64 @@
+/**
+ * Defines the structure of a user
+ */
+export interface User {
+	/**
+	 * Name of the user
+	 */
+	username: string
+
+	/**
+	 * Hashed password. Passwords are hashed using bcrypt.
+	 */
+	passhash: string
+
+	/**
+	 * Token used for upload authentication
+	 */
+	token: string
+
+	/**
+	 * Indicates whether the user is an admin
+	 */
+	admin: boolean
+
+	/**
+	 * Extra metadata. Frontends can use this to store extra data.
+	 */
+	meta: {
+		[key: string]: any
+	}
+}
+
+/**
+ * Defines the structure of the users.json file
+ */
+export interface Users {
+	/**
+	 * List of users. The key is the user's unique ID.
+	 */
+	users: {
+		[key: string]: User
+	}
+
+	/**
+	 * Indicates whether auth.json has been migrated
+	 */
+	migrated?: boolean
+
+	/**
+	 * Extra metadata. Frontends can use this to store extra data.
+	 */
+	meta: {
+		[key: string]: any
+	}
+}
+
+export interface OldUser {
+	username: string
+	count: number
+}
+
+export interface OldUsers {
+	[key: string]: OldUser
+}