diff --git a/app/Http/Controllers/ESign/EsignApiController.php b/app/Http/Controllers/ESign/EsignApiController.php
index 15089440..005ae234 100644
--- a/app/Http/Controllers/ESign/EsignApiController.php
+++ b/app/Http/Controllers/ESign/EsignApiController.php
@@ -1047,7 +1047,7 @@ private function sendAlimtalk(
             $expires = $contract->expires_at?->format('Y-m-d H:i') ?? '없음';
 
             if (! $templateName) {
-                $templateName = $isReminder ? '전자계약_리마인드' : '전자계약_서명요청';
+                $templateName = $this->resolveTemplateName($isReminder ? '전자계약_리마인드' : '전자계약_서명요청');
             }
 
             // 등록된 템플릿 본문 + 버튼 정보 조회 (정확한 포맷 유지)
@@ -1208,6 +1208,14 @@ private function getKakaotalkChannelId(BarobillService $barobill, string $bizNo)
      *
      * @return array{content: string|null, buttons: array}
      */
+    /**
+     * 환경별 알림톡 템플릿명 반환 (운영: 원본, 개발: _DEV 접미사)
+     */
+    private function resolveTemplateName(string $baseName): string
+    {
+        return $baseName.(app()->environment('production') ? '' : '_DEV');
+    }
+
     private function getTemplateData(BarobillService $barobill, string $bizNo, string $channelId, string $templateName): array
     {
         $empty = ['content' => null, 'buttons' => []];
diff --git a/app/Http/Controllers/ESign/EsignPublicController.php b/app/Http/Controllers/ESign/EsignPublicController.php
index 192fecb2..6a86563f 100644
--- a/app/Http/Controllers/ESign/EsignPublicController.php
+++ b/app/Http/Controllers/ESign/EsignPublicController.php
@@ -483,7 +483,8 @@ public function submitSignature(Request $request, string $token): JsonResponse
 
                             if ($channelId) {
                                 // 템플릿 본문 + 버튼 조회
-                                $tplData = $this->getTemplateData($barobill, $member->biz_no, $channelId, '전자계약_서명요청');
+                                $nextTemplateName = $this->resolveTemplateName('전자계약_서명요청');
+                                $tplData = $this->getTemplateData($barobill, $member->biz_no, $channelId, $nextTemplateName);
                                 $tplMessage = $tplData['content']
                                     ? str_replace(
                                         ['#{이름}', '#{계약명}', '#{기한}'],
@@ -513,7 +514,7 @@ public function submitSignature(Request $request, string $token): JsonResponse
                                     corpNum: $member->biz_no,
                                     senderId: $member->barobill_id,
                                     yellowId: $channelId,
-                                    templateName: '전자계약_서명요청',
+                                    templateName: $nextTemplateName,
                                     receiverName: $nextSigner->name,
                                     receiverNum: preg_replace('/[^0-9]/', '', $nextSigner->phone),
                                     title: '',
@@ -753,7 +754,7 @@ private function sendCompletionAlimtalk(EsignContract $contract, EsignSigner $si
                 return ['success' => false, 'channel' => 'alimtalk', 'error' => '등록된 카카오톡 채널이 없습니다'];
             }
 
-            $templateName = '전자계약_완료';
+            $templateName = $this->resolveTemplateName('전자계약_완료');
             $documentUrl = config('app.url').'/esign/sign/'.$signer->access_token.'/api/document';
             $signUrl = config('app.url').'/esign/sign/'.$signer->access_token;
             $completedAt = $contract->completed_at?->format('Y-m-d H:i') ?? now()->format('Y-m-d H:i');
@@ -974,6 +975,14 @@ private function getTemplateData(BarobillService $barobill, string $bizNo, strin
         return $empty;
     }
 
+    /**
+     * 환경별 알림톡 템플릿명 반환 (운영: 원본, 개발: _DEV 접미사)
+     */
+    private function resolveTemplateName(string $baseName): string
+    {
+        return $baseName.(app()->environment('production') ? '' : '_DEV');
+    }
+
     private function findSigner(string $token): ?EsignSigner
     {
         $signer = EsignSigner::withoutGlobalScopes()