diff --git a/genti-api/src/main/java/com/gt/genti/purchase/api/UserPurchaseApi.java b/genti-api/src/main/java/com/gt/genti/purchase/api/UserPurchaseApi.java
new file mode 100644
index 0000000..d8dc280
--- /dev/null
+++ b/genti-api/src/main/java/com/gt/genti/purchase/api/UserPurchaseApi.java
@@ -0,0 +1,27 @@
+package com.gt.genti.purchase.api;
+
+import com.gt.genti.error.ResponseCode;
+import com.gt.genti.purchase.dto.request.PurchaseRequestDto;
+import com.gt.genti.response.GentiResponse;
+import com.gt.genti.swagger.AuthorizedUser;
+import com.gt.genti.swagger.EnumResponse;
+import com.gt.genti.swagger.EnumResponses;
+import com.gt.genti.user.model.AuthUser;
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.tags.Tag;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.RequestBody;
+
+@AuthorizedUser
+@Tag(name = "[UserPurchaseController] 인앱 결제 컨트롤러", description = "결제 내용을 서버에서 검증합니다.")
+public interface UserPurchaseApi {
+
+    @Operation(summary = "영수증 검증", description = "클라이언트로부터 받은 결제 내역을 검증합니다.")
+    @EnumResponses(value = {
+            @EnumResponse(ResponseCode.OK),
+            @EnumResponse(ResponseCode.UserNotFound)
+    })
+    ResponseEntity<GentiResponse.ApiResult<Boolean>> validateReceipt(
+            @AuthUser Long userId,
+            @RequestBody PurchaseRequestDto purchaseRequestDto);
+}
diff --git a/genti-api/src/main/java/com/gt/genti/purchase/controller/UserPurchaseController.java b/genti-api/src/main/java/com/gt/genti/purchase/controller/UserPurchaseController.java
index 1584f0c..eb701f3 100644
--- a/genti-api/src/main/java/com/gt/genti/purchase/controller/UserPurchaseController.java
+++ b/genti-api/src/main/java/com/gt/genti/purchase/controller/UserPurchaseController.java
@@ -1,5 +1,6 @@
 package com.gt.genti.purchase.controller;
 
+import com.gt.genti.purchase.api.UserPurchaseApi;
 import com.gt.genti.purchase.dto.request.PurchaseRequestDto;
 import com.gt.genti.purchase.service.InAppPurchaseService;
 import com.gt.genti.response.GentiResponse;
@@ -14,7 +15,7 @@
 @RestController
 @RequestMapping("/api/v1/users/in-app-purchases")
 @RequiredArgsConstructor
-public class UserPurchaseController {
+public class UserPurchaseController implements UserPurchaseApi {
 
     private final InAppPurchaseService inAppPurchaseService;