diff --git a/src/main/java/com/icomsys/MessagingConnector.java b/src/main/java/com/icomsys/MessagingConnector.java
index bcecfe1..3b68a93 100644
--- a/src/main/java/com/icomsys/MessagingConnector.java
+++ b/src/main/java/com/icomsys/MessagingConnector.java
@@ -38,7 +38,7 @@ public class MessagingConnector {
 
     public MessageSendResponse messageDiv(MessageSendRequest messageSendRequest) throws IOException, InterruptedException {
         String url = sms;
-        String key = UUID.randomUUID().toString().substring(0, 7);
+        String key = UUID.randomUUID().toString().substring(0, 6);
         LocalDate now = LocalDate.now();
         messageSendRequest.setUserKey(now.toString().substring(2).replace("-", "") + key);
 
@@ -76,20 +76,20 @@ public class MessagingConnector {
 
         try {
             ObjectMapper objectMapper = new ObjectMapper();
-            Map<String, String> body = prepareRequestBody(messageSendRequest, objectMapper);
-            System.out.println("body : " + body);
+            Map<String, String> body = this.prepareRequestBody(messageSendRequest, objectMapper);
+            String boundary = "----WebKitFormBoundary" + System.currentTimeMillis();
 
-            String jsonBody = objectMapper.writeValueAsString(body);
-            System.out.println("jsonbody : " + jsonBody);
+            // Multipart body 생성
+            HttpRequest.BodyPublisher bodyPublisher = createMultipartBody(body, boundary);
 
             HttpRequest request = HttpRequest.newBuilder()
                     .uri(URI.create(url))
-                    .header("Content-Type", "application/json")
-                    .header("sejongApiKey", apiKey)
-                    .POST(HttpRequest.BodyPublishers.ofString(jsonBody))
+                    .header("Content-Type", "multipart/form-data; boundary=" + boundary)
+                    .header("sejongApiKey", this.apiKey)
+                    .POST(bodyPublisher)
                     .build();
 
-            HttpResponse<String> response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());
+            HttpResponse<String> response = this.httpClient.send(request, HttpResponse.BodyHandlers.ofString());
             System.out.println("responseCode : " + response.statusCode());
             System.out.println("responseBody : " + response.body());
             System.out.println("responseFull : " + response);
@@ -101,18 +101,18 @@ public class MessagingConnector {
                 messageSendResponse.setMessage("서버 통신 오류");
             }
         } catch (Exception e) {
+            e.printStackTrace();
             messageSendResponse.setCode("500");
             messageSendResponse.setMessage("서버 통신 오류");
         }
 
         messageSendResponse = this.responseChange(sejongMessageSendResponse, messageSendRequest);
-        messageSendServiceDsl.insertSendLog(sejongMessageSendResponse, messageSendRequest, messageSendResponse);
+        this.messageSendServiceDsl.insertSendLog(sejongMessageSendResponse, messageSendRequest, messageSendResponse);
 
-        if ("KAKAO".equals(messageSendRequest.getSendType()) && "Y".equals(messageSendRequest.getOptionYn())) {
-            if (!Objects.equals(sejongMessageSendResponse.getCode(), "200")) {
-                messageSendRequest.setSendType("");
-                messageSendResponse = this.messageDiv(messageSendRequest);
-            }
+        if ("KAKAO".equals(messageSendRequest.getSendType()) && "Y".equals(messageSendRequest.getOptionYn()) &&
+                !Objects.equals(sejongMessageSendResponse.getCode(), "200")) {
+            messageSendRequest.setSendType("");
+            messageSendResponse = this.messageDiv(messageSendRequest);
         }
 
         return messageSendResponse;
@@ -133,6 +133,21 @@ public class MessagingConnector {
         }
     }
 
+    private HttpRequest.BodyPublisher createMultipartBody(Map<String, String> body, String boundary) {
+        StringBuilder multipartBody = new StringBuilder();
+
+        for (Map.Entry<String, String> entry : body.entrySet()) {
+            multipartBody.append("--").append(boundary).append("\r\n");
+            multipartBody.append("Content-Disposition: form-data; name=\"").append(entry.getKey()).append("\"\r\n\r\n");
+            multipartBody.append(entry.getValue()).append("\r\n");
+        }
+
+        // 마지막 바운더리 추가
+        multipartBody.append("--").append(boundary).append("--\r\n");
+
+        return HttpRequest.BodyPublishers.ofString(multipartBody.toString());
+    }
+
     public MessageSendResponse responseChange(SejongMessageSendResponse response, MessageSendRequest request) {
         MessageSendResponse messageSendResponse = new MessageSendResponse();
         messageSendResponse.setSendType(request.getSendType());