diff --git a/web/lib/types.ts b/web/lib/types.ts
new file mode 100644
index 0000000..c59a0f3
--- /dev/null
+++ b/web/lib/types.ts
@@ -0,0 +1,24 @@
+// Mirrors the SQL schema in docker/mysql/init.d/01-schema.sql and the
+// JSON projection from app/cm_api.py's get_account / get_user routes.
+
+export type Acc = {
+  username: string;
+  password: string;
+  status: string;
+  link: string;
+};
+
+export type User = {
+  f_username: string;
+  f_password: string;
+  t_username: string;
+  t_password: string;
+  last_update_time: string | null;
+};
+
+export type AccUpdate = Acc;
+
+export type UserUpdate = Pick<
+  User,
+  "f_username" | "f_password" | "t_username" | "t_password"
+>;