diff --git a/application/Auth.ts b/application/Auth.ts
new file mode 100644
index 0000000..8cfaf2c
--- /dev/null
+++ b/application/Auth.ts
@@ -0,0 +1,19 @@
+export interface SignInRequest {
+  email: string;
+  password: string;
+}
+
+export interface SignInResponse {
+  succeed: boolean;
+  error?: string;
+}
+
+export interface SignUpRequest {
+  email: string;
+  password: string;
+}
+
+export interface SignUpResponse {
+  succeed: boolean;
+  error?: string;
+}