diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
index 8dd1719..c9b38f8 100644
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -4,6 +4,7 @@ on:
   push:
     branches:
       - main
+      - feature/kakao-api
 jobs:
   deploy:
     runs-on: ubuntu-latest
@@ -60,6 +61,8 @@ jobs:
             
             export DB_PASSWORD='${{ secrets.DB_PASSWORD }}'
             export DISCORD_TOKEN='${{ secrets.DISCORD_TOKEN }}'
+            export KAKAO_REST_API_KEY='${{ secrets.KAKAO_REST_API_KEY }}'
+            export KAKAO_EVENT_API_KEY='${{ secrets.KAKAO_EVENT_API_KEY }}'
             
             nohup java -jar build/libs/workingdead-0.0.1-SNAPSHOT.jar > app.log 2>&1 &
           
diff --git a/src/main/java/com/workingdead/chatbot/discord/service/DiscordWendyServiceImpl.java b/src/main/java/com/workingdead/chatbot/discord/service/DiscordWendyServiceImpl.java
index 16a2e50..2550c78 100644
--- a/src/main/java/com/workingdead/chatbot/discord/service/DiscordWendyServiceImpl.java
+++ b/src/main/java/com/workingdead/chatbot/discord/service/DiscordWendyServiceImpl.java
@@ -101,7 +101,7 @@ public void addParticipant(String channelId, String memberId, String memberName)
             return;
         }
 
-        ParticipantRes pRes = participantService.add(voteId, memberName);
+        ParticipantRes pRes = participantService.add(voteId, null, memberName);
         System.out.println("[Discord When:D] Participant added AFTER vote: " + memberName
                 + " (discordId=" + memberId + ", participantId=" + pRes.id() + ")");
     }
diff --git a/src/main/java/com/workingdead/chatbot/kakao/controller/KakaoSkillController.java b/src/main/java/com/workingdead/chatbot/kakao/controller/KakaoSkillController.java
index 419c264..8630dd9 100644
--- a/src/main/java/com/workingdead/chatbot/kakao/controller/KakaoSkillController.java
+++ b/src/main/java/com/workingdead/chatbot/kakao/controller/KakaoSkillController.java
@@ -16,7 +16,6 @@
  * 카카오 i 오픈빌더 스킬 서버 컨트롤러
  *
  * 카카오톡 챗봇에서 발화를 받아 처리하고 응답을 반환합니다.
- * - 개인챗: userKey 기반 세션
  * - 그룹챗: botGroupKey 기반 세션
  */
 @Tag(name = "Kakao Chatbot", description = "카카오 챗봇 스킬 API")
@@ -29,16 +28,6 @@ public class KakaoSkillController {
     private final KakaoWendyService kakaoWendyService;
     private final ObjectMapper objectMapper;
 
-    /**
-     * 세션 키 결정 (그룹챗이면 botGroupKey, 개인챗이면 userKey)
-     */
-    private String getSessionKey(KakaoRequest request) {
-        String botGroupKey = request.getBotGroupKey();
-        if (botGroupKey != null && !botGroupKey.isBlank()) {
-            return botGroupKey;
-        }
-        return request.getUserKey();
-    }
 
     /**
      * 메인 스킬 엔드포인트 (폴백 블록)
@@ -47,7 +36,6 @@ private String getSessionKey(KakaoRequest request) {
     @Operation(summary = "메인 스킬 (폴백)")
     @PostMapping("/main")
     public ResponseEntity<KakaoResponse> handleMain(@RequestBody KakaoRequest request) {
-        String sessionKey = getSessionKey(request);
         String botGroupKey = request.getBotGroupKey();
         String botUserKey = request.getBotUserKey();
         String utterance = request.getUtterance();
@@ -58,18 +46,12 @@ public ResponseEntity<KakaoResponse> handleMain(@RequestBody KakaoRequest reques
             log.warn("[Kakao Skill] Failed to log raw request: {}", e.getMessage());
         }
 
-
-
-        log.info("[Kakao Skill] sessionKey={}, botGroupKey={}, botUserKey={}, utterance={}",
-                sessionKey, botGroupKey, botUserKey, utterance);
-
-        if (sessionKey == null || sessionKey.isBlank()) {
-            log.warn("[Kakao Skill] Missing sessionKey. botGroupKey={}, userKey={}, botUserKey={}",
-                    botGroupKey, request.getUserKey(), botUserKey);
-            return ResponseEntity.ok(kakaoWendyService.help());
+        if (botGroupKey == null || botGroupKey.isBlank()) {
+            return ResponseEntity.ok(KakaoResponse.simpleText(
+                "이 기능은 그룹 채팅방에서만 사용할 수 있어요. 그룹방에서 @웬디를 불러주세요!"
+            ));
         }
 
-
         if (utterance == null || utterance.isBlank()) {
             return ResponseEntity.ok(kakaoWendyService.help());
         }
@@ -78,7 +60,7 @@ public ResponseEntity<KakaoResponse> handleMain(@RequestBody KakaoRequest reques
 
         // 1. 웬디 시작
         if (trimmed.equals("웬디 시작") || trimmed.equals("시작")) {
-            return ResponseEntity.ok(kakaoWendyService.startSession(sessionKey, botGroupKey));
+            return ResponseEntity.ok(kakaoWendyService.startSession(botGroupKey));
         }
 
         // 2. 도움말
@@ -88,21 +70,21 @@ public ResponseEntity<KakaoResponse> handleMain(@RequestBody KakaoRequest reques
 
         // 3. 웬디 종료
         if (trimmed.equals("웬디 종료") || trimmed.equals("종료")) {
-            return ResponseEntity.ok(kakaoWendyService.endSession(sessionKey));
+            return ResponseEntity.ok(kakaoWendyService.endSession(botGroupKey));
         }
 
         // 4. 웬디 결과
         if (trimmed.equals("웬디 결과") || trimmed.equals("결과") || trimmed.equals("결과 확인")) {
-            return ResponseEntity.ok(kakaoWendyService.getVoteResult(sessionKey));
+            return ResponseEntity.ok(kakaoWendyService.getVoteResult(botGroupKey));
         }
 
         // 5. 웬디 재투표
         if (trimmed.equals("웬디 재투표") || trimmed.equals("재투표")) {
-            return ResponseEntity.ok(kakaoWendyService.revote(sessionKey));
+            return ResponseEntity.ok(kakaoWendyService.revote(botGroupKey));
         }
 
         // 6. 웬디 {기간} (예: "웬디 2주 후", "웬디 이번주")
-        // 멘션/푸시 기능 없이, 기간 입력을 받으면 바로 투표 URL을 생성해 반환
+        // 기간 입력을 받으면 서버에서 날짜 범위를 계산해 투표를 생성하고 /open-vote 링크를 제공합니다.
         if (trimmed.startsWith("웬디 ")) {
             String arg = trimmed.substring("웬디 ".length()).trim();
             // 예약어는 위에서 이미 처리했지만, 안전하게 한 번 더 방어
@@ -115,39 +97,38 @@ public ResponseEntity<KakaoResponse> handleMain(@RequestBody KakaoRequest reques
                     && !arg.equals("독촉")) {
                 Integer weeks = kakaoWendyService.parseWeeks(arg);
                 if (weeks != null) {
-                    KakaoResponse response = kakaoWendyService.createVote(sessionKey, weeks, botGroupKey);
+                    KakaoResponse response = kakaoWendyService.createVote(botGroupKey, weeks);
                     return ResponseEntity.ok(response);
                 }
             }
         }
 
-
         // 세션 상태에 따른 처리
-        SessionState state = kakaoWendyService.getSessionState(sessionKey);
+        SessionState state = kakaoWendyService.getSessionState(botGroupKey);
 
         switch (state) {
-            case WAITING_PARTICIPANTS:
-                // 참석자 입력: PRD 기준으로 botUserKey(멘션된 유저 키) 기반을 우선 사용
-                // 멘션 기반 참석자 수집 기능을 사용하지 않는 정책으로 전환
+            case IDLE:
                 return ResponseEntity.ok(KakaoResponse.simpleText(
-                        "\"@웬디 2주 후\"처럼 기간을 입력하면 바로 날짜 투표 링크를 만들어드릴게요!"
+                        "\"웬디 시작\"을 입력해 투표를 시작해 주세요!"
                 ));
-
             case WAITING_WEEKS:
                 // 주차 선택
-                Integer weeks = kakaoWendyService.parseWeeks(trimmed);
-                if (weeks != null) {
-                    KakaoResponse response = kakaoWendyService.createVote(sessionKey, weeks, botGroupKey);
-                    return ResponseEntity.ok(response);
-                }
-                break;
-
+                return ResponseEntity.ok(KakaoResponse.simpleText(
+                        "기간을 선택해 주세요! 예) 이번주, 다음주, 2주 후"
+                ));
+            case VOTE_CREATED:
+                return ResponseEntity.ok(KakaoResponse.simpleText(
+                        "이미 진행 중인 투표가 있어요.\n" +
+                        "- 결과: \"웬디 결과\"\n" +
+                        "- 새로 시작: \"웬디 재투표\"\n\n" +
+                        "투표하러 가기: /open-vote"
+                ));
             default:
                 break;
         }
 
         // 알 수 없는 입력
-        return ResponseEntity.ok(kakaoWendyService.unknownInput(sessionKey));
+        return ResponseEntity.ok(kakaoWendyService.unknownInput(botGroupKey));
     }
 
     /**
@@ -156,10 +137,14 @@ public ResponseEntity<KakaoResponse> handleMain(@RequestBody KakaoRequest reques
     @Operation(summary = "웬디 시작")
     @PostMapping("/start")
     public ResponseEntity<KakaoResponse> handleStart(@RequestBody KakaoRequest request) {
-        String sessionKey = getSessionKey(request);
         String botGroupKey = request.getBotGroupKey();
-        log.info("[Kakao Skill] START - sessionKey={}, botGroupKey={}", sessionKey, botGroupKey);
-        return ResponseEntity.ok(kakaoWendyService.startSession(sessionKey, botGroupKey));
+        log.info("botGroupKey={}", request.getBotGroupKey());
+        if (botGroupKey == null || botGroupKey.isBlank()) {
+            return ResponseEntity.ok(KakaoResponse.simpleText(
+                "이 기능은 그룹 채팅방에서만 사용할 수 있어요. 그룹방에서 @웬디를 불러주세요!"
+            ));
+        }
+        return ResponseEntity.ok(kakaoWendyService.startSession(botGroupKey));
     }
 
     /**
@@ -170,10 +155,14 @@ public ResponseEntity<KakaoResponse> handleStart(@RequestBody KakaoRequest reque
     @Operation(summary = "참석자 등록")
     @PostMapping("/participants")
     public ResponseEntity<KakaoResponse> handleParticipants(@RequestBody KakaoRequest request) {
-        String sessionKey = getSessionKey(request);
-        log.info("[Kakao Skill] PARTICIPANTS - disabled. sessionKey={}", sessionKey);
+        String botGroupKey = request.getBotGroupKey();
+        if (botGroupKey == null || botGroupKey.isBlank()) {
+            return ResponseEntity.ok(KakaoResponse.simpleText(
+                "이 기능은 그룹 채팅방에서만 사용할 수 있어요. 그룹방에서 @웬디를 불러주세요!"
+            ));
+        }
         return ResponseEntity.ok(KakaoResponse.simpleText(
-                "\"@웬디 2주 후\"처럼 기간을 입력하면 날짜 투표 링크를 만들어드릴게요!"
+                "참석자 단계는 생략했어요. 기간을 입력해 주세요! 예) 이번주, 다음주, 2주 후"
         ));
     }
 
@@ -183,9 +172,13 @@ public ResponseEntity<KakaoResponse> handleParticipants(@RequestBody KakaoReques
     @Operation(summary = "웬디 종료")
     @PostMapping("/end")
     public ResponseEntity<KakaoResponse> handleEnd(@RequestBody KakaoRequest request) {
-        String sessionKey = getSessionKey(request);
-        log.info("[Kakao Skill] END - sessionKey={}", sessionKey);
-        return ResponseEntity.ok(kakaoWendyService.endSession(sessionKey));
+        String botGroupKey = request.getBotGroupKey();
+        if (botGroupKey == null || botGroupKey.isBlank()) {
+            return ResponseEntity.ok(KakaoResponse.simpleText(
+                "이 기능은 그룹 채팅방에서만 사용할 수 있어요. 그룹방에서 @웬디를 불러주세요!"
+            ));
+        }
+        return ResponseEntity.ok(kakaoWendyService.endSession(botGroupKey));
     }
 
     /**
@@ -195,22 +188,20 @@ public ResponseEntity<KakaoResponse> handleEnd(@RequestBody KakaoRequest request
     @Operation(summary = "주차 선택")
     @PostMapping("/select-week")
     public ResponseEntity<KakaoResponse> handleSelectWeek(@RequestBody KakaoRequest request) {
-        String sessionKey = getSessionKey(request);
         String botGroupKey = request.getBotGroupKey();
         String weeksParam = request.getParam("weeks");
+        log.info("[SKILL] select-week called botGroupKey={}", botGroupKey);
 
-        log.info("[Kakao Skill] SELECT_WEEK - sessionKey={}, botGroupKey={}, weeksParam={}", sessionKey, botGroupKey, weeksParam);
-
-        if (sessionKey == null || sessionKey.isBlank()) {
-            log.warn("[Kakao Skill] SELECT_WEEK missing sessionKey. botGroupKey={}, userKey={}",
-                    botGroupKey, request.getUserKey());
-            return ResponseEntity.ok(KakaoResponse.simpleText("세션 정보를 확인하지 못했어요. 다시 시작해 주세요."));
+        if (botGroupKey == null || botGroupKey.isBlank()) {
+            return ResponseEntity.ok(KakaoResponse.simpleText(
+                "이 기능은 그룹 채팅방에서만 사용할 수 있어요. 그룹방에서 @웬디를 불러주세요!"
+            ));
         }
+
         // 상태 검증: 주차 선택 단계에서만 허용
-        SessionState state = kakaoWendyService.getSessionState(sessionKey);
+        SessionState state = kakaoWendyService.getSessionState(botGroupKey);
         if (state != SessionState.WAITING_WEEKS) {
-            log.warn("[Kakao Skill] SELECT_WEEK called in invalid state. sessionKey={}, state={}", sessionKey, state);
-            return ResponseEntity.ok(kakaoWendyService.unknownInput(sessionKey));
+            return ResponseEntity.ok(kakaoWendyService.unknownInput(botGroupKey));
         }
 
         // weeks 파싱 (param 우선, 없으면 utterance로 보조)
@@ -218,11 +209,10 @@ public ResponseEntity<KakaoResponse> handleSelectWeek(@RequestBody KakaoRequest
         Integer weeks = (candidate == null) ? null : kakaoWendyService.parseWeeks(candidate.trim());
 
         if (weeks == null || weeks < 0) {
-            log.warn("[Kakao Skill] SELECT_WEEK invalid weeks. sessionKey={}, candidate={}", sessionKey, candidate);
             return ResponseEntity.ok(KakaoResponse.simpleText("주차 선택 값을 확인하지 못했어요. 다시 선택해 주세요."));
         }
 
-        KakaoResponse response = kakaoWendyService.createVote(sessionKey, weeks, botGroupKey);
+        KakaoResponse response = kakaoWendyService.createVote(botGroupKey, weeks);
         return ResponseEntity.ok(response);
     }
 
@@ -232,9 +222,13 @@ public ResponseEntity<KakaoResponse> handleSelectWeek(@RequestBody KakaoRequest
     @Operation(summary = "투표 결과 조회")
     @PostMapping("/result")
     public ResponseEntity<KakaoResponse> handleResult(@RequestBody KakaoRequest request) {
-        String sessionKey = getSessionKey(request);
-        log.info("[Kakao Skill] RESULT - sessionKey={}", sessionKey);
-        return ResponseEntity.ok(kakaoWendyService.getVoteResult(sessionKey));
+        String botGroupKey = request.getBotGroupKey();
+        if (botGroupKey == null || botGroupKey.isBlank()) {
+            return ResponseEntity.ok(KakaoResponse.simpleText(
+                "이 기능은 그룹 채팅방에서만 사용할 수 있어요. 그룹방에서 @웬디를 불러주세요!"
+            ));
+        }
+        return ResponseEntity.ok(kakaoWendyService.getVoteResult(botGroupKey));
     }
 
     /**
@@ -243,9 +237,13 @@ public ResponseEntity<KakaoResponse> handleResult(@RequestBody KakaoRequest requ
     @Operation(summary = "재투표")
     @PostMapping("/revote")
     public ResponseEntity<KakaoResponse> handleRevote(@RequestBody KakaoRequest request) {
-        String sessionKey = getSessionKey(request);
-        log.info("[Kakao Skill] REVOTE - sessionKey={}", sessionKey);
-        return ResponseEntity.ok(kakaoWendyService.revote(sessionKey));
+        String botGroupKey = request.getBotGroupKey();
+        if (botGroupKey == null || botGroupKey.isBlank()) {
+            return ResponseEntity.ok(KakaoResponse.simpleText(
+                "이 기능은 그룹 채팅방에서만 사용할 수 있어요. 그룹방에서 @웬디를 불러주세요!"
+            ));
+        }
+        return ResponseEntity.ok(kakaoWendyService.revote(botGroupKey));
     }
 
     /**
@@ -254,7 +252,6 @@ public ResponseEntity<KakaoResponse> handleRevote(@RequestBody KakaoRequest requ
     @Operation(summary = "도움말")
     @PostMapping("/help")
     public ResponseEntity<KakaoResponse> handleHelp(@RequestBody KakaoRequest request) {
-        log.info("[Kakao Skill] HELP - sessionKey={}", getSessionKey(request));
         return ResponseEntity.ok(kakaoWendyService.help());
     }
 
@@ -266,56 +263,4 @@ public ResponseEntity<KakaoResponse> handleHelp(@RequestBody KakaoRequest reques
     public ResponseEntity<String> health() {
         return ResponseEntity.ok("OK");
     }
-
-
-    /**
-     * 참석자 botUserKey 목록 추출
-     * - 오픈빌더의 "발화에서 멘션된 유저 식별" 결과를 params로 전달받는 것을 1순위로 사용
-     * - 지원 키: botUserKeys / participants / mentionedUserKeys
-     * - 값 형태: "k1,k2,k3" 또는 "k1 k2 k3" 등(구분자는 콤마/공백/개행 모두 허용)
-     *
-     * @param request 요청 DTO
-     * @param fallbackUtterance params가 없을 때 마지막 fallback(테스트/디버그용)
-     * @return 콤마(,)로 join된 botUserKey 목록 문자열
-     */
-    private String extractParticipantKeys(KakaoRequest request, String fallbackUtterance) {
-        String raw = firstNonBlank(
-                request.getParam("botUserKeys"),
-                request.getParam("participants"),
-                request.getParam("mentionedUserKeys")
-        );
-
-        if (raw == null || raw.isBlank()) {
-            raw = (fallbackUtterance == null) ? "" : fallbackUtterance;
-        }
-
-        return normalizeKeys(raw);
-    }
-
-    private String firstNonBlank(String... values) {
-        if (values == null) return null;
-        for (String v : values) {
-            if (v != null && !v.isBlank()) return v;
-        }
-        return null;
-    }
-
-    /**
-     * 다양한 구분자(콤마/공백/개행)를 콤마 구분 문자열로 정규화
-     */
-    private String normalizeKeys(String raw) {
-        if (raw == null) return "";
-        String trimmed = raw.trim();
-        if (trimmed.isEmpty()) return "";
-
-        // 콤마, 공백, 개행, 탭을 모두 구분자로 처리
-        String[] parts = trimmed.split("[\\s,]+");
-        java.util.LinkedHashSet<String> set = new java.util.LinkedHashSet<>();
-        for (String p : parts) {
-            if (p == null) continue;
-            String s = p.trim();
-            if (!s.isEmpty()) set.add(s);
-        }
-        return String.join(",", set);
-    }
 }
\ No newline at end of file
diff --git a/src/main/java/com/workingdead/chatbot/kakao/dto/KakaoRequest.java b/src/main/java/com/workingdead/chatbot/kakao/dto/KakaoRequest.java
index e0531ab..683cca0 100644
--- a/src/main/java/com/workingdead/chatbot/kakao/dto/KakaoRequest.java
+++ b/src/main/java/com/workingdead/chatbot/kakao/dto/KakaoRequest.java
@@ -29,6 +29,15 @@ public class KakaoRequest {
     public static class Chat {
         private String id;      // 채팅방 ID (botGroupKey)
         private String type;    // 채팅방 타입
+        private ChatProperties properties;
+    }
+
+    @Getter
+    @Setter
+    @NoArgsConstructor
+    @JsonIgnoreProperties(ignoreUnknown = true)
+    public static class ChatProperties {
+        private String botGroupKey;
     }
 
     @Getter
@@ -51,6 +60,7 @@ public static class UserRequest {
         private String utterance;
         private String lang;
         private User user;
+        private Chat chat;
     }
 
     @Getter
@@ -80,6 +90,7 @@ public static class Properties {
         private String plusfriendUserKey;
         private String appUserId;
         private Boolean isFriend;
+        private String botUserKey;
     }
 
     @Getter
@@ -152,10 +163,26 @@ public String getBotId() {
 
     /**
      * 그룹 채팅방 키 (botGroupKey) 조회
+     * - 카카오 요청에서는 userRequest.chat.id 가 botGroupKey로 사용 가능하며,
+     *   userRequest.chat.properties.botGroupKey 로도 전달됩니다.
      */
     public String getBotGroupKey() {
+        // 1) userRequest.chat.id (요청에 기본 포함)
+        if (userRequest != null && userRequest.getChat() != null) {
+            String id = userRequest.getChat().getId();
+            if (id != null && !id.isBlank()) return id;
+
+            // 2) userRequest.chat.properties.botGroupKey
+            if (userRequest.getChat().getProperties() != null) {
+                String key = userRequest.getChat().getProperties().getBotGroupKey();
+                if (key != null && !key.isBlank()) return key;
+            }
+        }
+
+        // 3) 호환: 최상위 chat.id (현재 JSON에는 없지만 혹시 몰라 유지)
         if (chat != null) {
-            return chat.getId();
+            String id = chat.getId();
+            if (id != null && !id.isBlank()) return id;
         }
         return null;
     }
@@ -164,16 +191,22 @@ public String getBotGroupKey() {
      * 그룹 채팅방 여부 확인
      */
     public boolean isGroupChat() {
-        return chat != null && chat.getId() != null;
+        String key = getBotGroupKey();
+        return key != null && !key.isBlank();
     }
 
     /**
      * 그룹챗 사용자 식별용 botUserKey
-     * - PRD 기준: 멘션/참석자 식별 키로 사용
-     * - 현재 구조에서는 user.id를 사용
+     * - 카카오 요청에서는 userRequest.user.properties.botUserKey 로 전달됩니다.
+     * - fallback: userRequest.user.id
      */
     public String getBotUserKey() {
         if (userRequest != null && userRequest.getUser() != null) {
+            Properties p = userRequest.getUser().getProperties();
+            if (p != null) {
+                String key = p.getBotUserKey();
+                if (key != null && !key.isBlank()) return key;
+            }
             String id = userRequest.getUser().getId();
             return (id == null || id.isBlank()) ? null : id;
         }
diff --git a/src/main/java/com/workingdead/chatbot/kakao/service/KakaoNotifier.java b/src/main/java/com/workingdead/chatbot/kakao/service/KakaoNotifier.java
index e6075fb..29cfe5d 100644
--- a/src/main/java/com/workingdead/chatbot/kakao/service/KakaoNotifier.java
+++ b/src/main/java/com/workingdead/chatbot/kakao/service/KakaoNotifier.java
@@ -7,8 +7,6 @@
 import com.workingdead.meet.dto.VoteResultDtos.VoteResultRes;
 import com.workingdead.meet.service.ParticipantService;
 import com.workingdead.meet.service.VoteResultService;
-import java.time.Duration;
-import java.time.LocalDateTime;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.http.*;
@@ -16,7 +14,6 @@
 import org.springframework.web.client.RestTemplate;
 
 import java.time.DayOfWeek;
-import java.time.LocalDate;
 import java.time.format.DateTimeFormatter;
 import java.util.*;
 import java.util.stream.Collectors;
@@ -69,16 +66,11 @@ public void sendEventToGroup(String botGroupKey, String eventName) {
     /**
      * 투표 현황 공유 (이벤트 메시지)
      */
-    public void shareVoteStatus(String sessionKey) {
+    public void shareVoteStatus(String botGroupKey) {
         try {
-            Long voteId = kakaoWendyService.getVoteIdBySessionKey(sessionKey);
+            Long voteId = kakaoWendyService.getVoteIdByBotGroupKey(botGroupKey);
             if (voteId == null) return;
 
-            LocalDateTime createdAt = kakaoWendyService.getVoteCreatedAtBySessionKey(sessionKey);
-            if (createdAt == null) return;
-
-            long elapsedSeconds = Duration.between(createdAt, LocalDateTime.now()).getSeconds();
-
             List<ParticipantStatusRes> statuses = participantService.getParticipantStatusByVoteId(voteId);
             long submittedCount = statuses.stream().filter(s -> Boolean.TRUE.equals(s.submitted())).count();
             long totalCount = statuses.size();
@@ -89,91 +81,68 @@ public void shareVoteStatus(String sessionKey) {
                 return;
             }
 
-
-            boolean allSubmitted = totalCount > 0 && submittedCount == totalCount;
-            boolean majoritySubmitted = totalCount > 0 && submittedCount * 2 >= totalCount; // 과반(>=)
-
-            // 3분 전 & 과반 미달이면 아무것도 안 보냄
-            if (elapsedSeconds < 180 && !majoritySubmitted && !allSubmitted) {
-                return;
-            }
-
-            // 3분 경과했는데 0명 투표면 안내 메시지
-            if (elapsedSeconds >= 180 && submittedCount == 0) {
-                sendToGroupIfPossible(voteId, "status_nobody_voted");
-                return;
+            if (submittedCount == 0) {
+                sendEventToGroup(botGroupKey, "status_nobody_voted");
+            } else {
+                sendEventToGroup(botGroupKey, "status_vote_result");
             }
 
-            // 결과 공유
-            sendToGroupIfPossible(voteId, "status_vote_result");
-
-            // 전원 투표 완료면 완료 단계로 이동 트리거
+            boolean allSubmitted = totalCount > 0 && submittedCount == totalCount;
             if (allSubmitted) {
-                sendToGroupIfPossible(voteId, "status_all_done");
+                sendEventToGroup(botGroupKey, "status_all_done");
             }
 
-
         } catch (Exception e) {
             log.error("[Kakao Notifier] Failed to share vote status: {}", e.getMessage());
         }
     }
 
-    public void sendFinalNotice(String sessionKey) {
+    public void sendFinalNotice(String botGroupKey) {
         try {
-            Long voteId = kakaoWendyService.getVoteIdBySessionKey(sessionKey);
+            Long voteId = kakaoWendyService.getVoteIdByBotGroupKey(botGroupKey);
             if (voteId == null) return;
 
             List<String> nonVoters = getNonVoterNames(voteId);
             if (nonVoters.isEmpty()) return; // 미투표자 없으면 전송 X
 
-            sendToGroupIfPossible(voteId, "final_notice_24h");
+            sendEventToGroup(botGroupKey, "final_notice_24h");
         } catch (Exception e) {
             log.error("[Kakao Notifier] sendFinalNotice failed: {}", e.getMessage(), e);
         }
     }
 
-    public void finalizeIfNoResponse(String sessionKey) {
+    public void finalizeIfNoResponse(String botGroupKey) {
         try {
-            Long voteId = kakaoWendyService.getVoteIdBySessionKey(sessionKey);
+            Long voteId = kakaoWendyService.getVoteIdByBotGroupKey(botGroupKey);
             if (voteId == null) return;
 
             List<String> nonVoters = getNonVoterNames(voteId);
             if (nonVoters.isEmpty()) return; // 이미 다 했으면 확정 처리 X
 
-            sendToGroupIfPossible(voteId, "finalize_after_60m");
+            sendEventToGroup(botGroupKey, "finalize_after_60m");
 
         } catch (Exception e) {
             log.error("[Kakao Notifier] finalizeIfNoResponse failed: {}", e.getMessage(), e);
         }
     }
 
-    private void sendToGroupIfPossible(Long voteId, String eventName) {
-        String botGroupKey = kakaoWendyService.getBotGroupKeyByVoteId(voteId);
-        if (botGroupKey != null && !botGroupKey.isBlank()) {
-            sendEventToGroup(botGroupKey, eventName);
-        } else {
-            log.info("[Kakao Notifier] Individual chat: voteId={}, eventName={} (cannot push)", voteId, eventName);
-        }
-    }
-
     /**
      * 미투표자 리마인드 (이벤트 메시지)
      */
-    public void remindNonVoters(String sessionKey, RemindTiming timing) {
+    public void remindNonVoters(String botGroupKey, RemindTiming timing) {
         try {
-            Long voteId = kakaoWendyService.getVoteIdBySessionKey(sessionKey);
+            Long voteId = kakaoWendyService.getVoteIdByBotGroupKey(botGroupKey);
             if (voteId == null) {
-                log.warn("[Kakao Notifier] No vote found for sessionKey: {}", sessionKey);
+                log.warn("[Kakao Notifier] No vote found for botGroupKey: {}", botGroupKey);
                 return;
             }
 
             List<String> nonVoters = getNonVoterNames(voteId);
             if (nonVoters.isEmpty()) {
-                log.info("[Kakao Notifier] No non-voters. Skip reminder: sessionKey={}, timing={}", sessionKey, timing);
+                log.info("[Kakao Notifier] No non-voters. Skip reminder: botGroupKey={}, timing={}", botGroupKey, timing);
                 return;
             }
 
-
             String eventName = switch (timing) {
                 case MIN_30 -> "remind_30min";
                 case HOUR_2 -> "remind_2hour";
@@ -181,14 +150,7 @@ public void remindNonVoters(String sessionKey, RemindTiming timing) {
                 case HOUR_12 -> "remind_12hour";
             };
 
-            // botGroupKey 조회 (그룹챗인 경우에만 이벤트 발송)
-            String botGroupKey = kakaoWendyService.getBotGroupKeyByVoteId(voteId);
-            if (botGroupKey != null) {
-                sendEventToGroup(botGroupKey, eventName);
-            } else {
-                log.info("[Kakao Notifier] Reminder for individual chat (cannot push): sessionKey={}, timing={}",
-                        sessionKey, timing);
-            }
+            sendEventToGroup(botGroupKey, eventName);
 
         } catch (Exception e) {
             log.error("[Kakao Notifier] Failed to send reminder: {}", e.getMessage());
@@ -247,56 +209,6 @@ public List<String> getNonVoterNames(Long voteId) {
                 .collect(Collectors.toList());
     }
 
-    /**
-     * 카카오 메시지 API 호출 (템플릿)
-     *
-     * 참고: 실제 사용하려면 카카오 비즈메시지 설정 필요
-     * - 카카오톡 채널 개설
-     * - 발신 프로필 등록
-     * - 알림톡 템플릿 승인
-     */
-//    public boolean sendKakaoMessage(String userKey, String templateId, Map<String, String> templateArgs) {
-//        try {
-//            String adminKey = kakaoConfig.getAdminKey();
-//            if (adminKey == null || adminKey.isBlank()) {
-//                log.warn("[Kakao Notifier] Admin key not configured. Message not sent.");
-//                return false;
-//            }
-//
-//            HttpHeaders headers = new HttpHeaders();
-//            headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);
-//            headers.set("Authorization", "KakaoAK " + adminKey);
-//
-//            // 템플릿 기반 메시지 구성
-//            Map<String, Object> templateObject = new HashMap<>();
-//            templateObject.put("object_type", "text");
-//            templateObject.put("text", templateArgs.getOrDefault("message", "웬디 알림"));
-//            templateObject.put("link", Map.of(
-//                    "web_url", templateArgs.getOrDefault("link", "https://whendy.netlify.app"),
-//                    "mobile_web_url", templateArgs.getOrDefault("link", "https://whendy.netlify.app")
-//            ));
-//
-//            String templateObjectJson = objectMapper.writeValueAsString(templateObject);
-//            String body = "receiver_uuids=[\"" + userKey + "\"]&template_object=" + templateObjectJson;
-//
-//            HttpEntity<String> request = new HttpEntity<>(body, headers);
-//
-//            ResponseEntity<String> response = kakaoRestTemplate.exchange(
-//                    KAKAO_FRIEND_MESSAGE_URL,
-//                    HttpMethod.POST,
-//                    request,
-//                    String.class
-//            );
-//
-//            log.info("[Kakao Notifier] Message sent. Response: {}", response.getBody());
-//            return response.getStatusCode().is2xxSuccessful();
-//
-//        } catch (Exception e) {
-//            log.error("[Kakao Notifier] Failed to send Kakao message: {}", e.getMessage());
-//            return false;
-//        }
-//    }
-
     private String getDayLabel(DayOfWeek dayOfWeek) {
         return switch (dayOfWeek) {
             case MONDAY -> "월";
diff --git a/src/main/java/com/workingdead/chatbot/kakao/service/KakaoWendyService.java b/src/main/java/com/workingdead/chatbot/kakao/service/KakaoWendyService.java
index fcdbb37..2cce9fd 100644
--- a/src/main/java/com/workingdead/chatbot/kakao/service/KakaoWendyService.java
+++ b/src/main/java/com/workingdead/chatbot/kakao/service/KakaoWendyService.java
@@ -1,12 +1,10 @@
 package com.workingdead.chatbot.kakao.service;
 
 import com.workingdead.chatbot.kakao.dto.KakaoResponse;
-import com.workingdead.meet.dto.ParticipantDtos.ParticipantStatusRes;
 import com.workingdead.meet.dto.VoteDtos.CreateVoteReq;
 import com.workingdead.meet.dto.VoteDtos.VoteSummary;
 import com.workingdead.meet.dto.VoteResultDtos.RankingRes;
 import com.workingdead.meet.dto.VoteResultDtos.VoteResultRes;
-import com.workingdead.meet.service.ParticipantService;
 import com.workingdead.meet.service.VoteResultService;
 import com.workingdead.meet.service.VoteService;
 import lombok.RequiredArgsConstructor;
@@ -15,17 +13,12 @@
 
 import java.time.DayOfWeek;
 import java.time.LocalDate;
-import java.time.LocalDateTime;
-import java.time.format.DateTimeFormatter;
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.stream.Collectors;
 
 /**
- * 카카오 챗봇용 웬디 서비스
- * Discord와 독립적으로 세션 관리
- * - 개인챗: userKey 기반
- * - 그룹챗: botGroupKey 기반
+ * - 그룹챗 전용: botGroupKey 기반
  */
 @Service
 @RequiredArgsConstructor
@@ -33,69 +26,37 @@
 public class KakaoWendyService {
 
     private final VoteService voteService;
-    private final ParticipantService participantService;
     private final VoteResultService voteResultService;
 
-    // ========== 세션 관리 (sessionKey = botGroupKey 또는 userKey) ==========
+    // ========== 세션 관리 (key = botGroupKey) ==========
 
     // 활성 세션 관리
     private final Set<String> activeSessions = ConcurrentHashMap.newKeySet();
-
-    // 참석자 목록 (sessionKey -> List<botUserKey>)
-    private final Map<String, List<String>> participants = new ConcurrentHashMap<>();
-
-    // 참석자 표시명 (sessionKey -> List<표시명>)
-    private final Map<String, List<String>> participantDisplayNames = new ConcurrentHashMap<>();
-
-    // 생성된 투표 ID (sessionKey -> voteId)
+    // 생성된 투표 ID (botGroupKey -> voteId)
     private final Map<String, Long> sessionVoteId = new ConcurrentHashMap<>();
-
-    // 생성된 투표 링크 (sessionKey -> shareUrl)
-    private final Map<String, String> sessionShareUrl = new ConcurrentHashMap<>();
-
-    // 투표 생성 시각 (sessionKey -> createdAt)
-    private final Map<String, LocalDateTime> voteCreatedAt = new ConcurrentHashMap<>();
-
-    // 세션 상태 (sessionKey -> state)
+    // 세션 상태 (botGroupKey -> state)
     private final Map<String, SessionState> sessionStates = new ConcurrentHashMap<>();
 
-    // botGroupKey -> voteId 매핑 (이벤트 메시지 발송용)
-    private final Map<String, Long> groupVoteId = new ConcurrentHashMap<>();
-
-    // voteId -> botGroupKey 역매핑
-    private final Map<Long, String> voteIdToGroupKey = new ConcurrentHashMap<>();
-
     public enum SessionState {
         IDLE,
-        WAITING_PARTICIPANTS,
         WAITING_WEEKS,
         VOTE_CREATED
     }
 
-    // ========== Deprecated: 하위 호환성 ==========
-    @Deprecated
-    private final Map<String, Long> userVoteId = sessionVoteId;
-    @Deprecated
-    private final Map<String, String> userShareUrl = sessionShareUrl;
-
-    // ========== 세션 관리 ==========
-
     /**
-     * 세션 시작 (웬디 시작)
+     * 세션 시작 (@웬디 시작)
+     * - 그룹챗 전용: botGroupKey를 세션 키로 사용
+     * - 다음 단계: 주차(기간) 선택 대기
      */
-    public KakaoResponse startSession(String userKey) {
-        activeSessions.add(userKey);
-        participants.put(userKey, new ArrayList<>());
-        participantDisplayNames.put(userKey, new ArrayList<>());
-        userVoteId.remove(userKey);
-        userShareUrl.remove(userKey);
-        voteCreatedAt.remove(userKey);
-        sessionStates.put(userKey, SessionState.WAITING_WEEKS);
+    public KakaoResponse startSession(String botGroupKey) {
+        activeSessions.add(botGroupKey);
+        sessionVoteId.remove(botGroupKey);
+        sessionStates.put(botGroupKey, SessionState.WAITING_WEEKS);
 
-        log.info("[Kakao When:D] Session started: {}", userKey);
+        log.info("[Kakao When:D] Session started: botGroupKey={}", botGroupKey);
 
         Map<String, Object> data = new HashMap<>();
-        data.put("sessionKey", userKey);
+        data.put("botGroupKey", botGroupKey);
         data.put("state", SessionState.WAITING_WEEKS.name());
         data.put("active", true);
         return dataOnly(data);
@@ -104,26 +65,29 @@ public KakaoResponse startSession(String userKey) {
     /**
      * 세션 활성 여부 확인
      */
-    public boolean isSessionActive(String userKey) {
-        return activeSessions.contains(userKey);
+    public boolean isSessionActive(String botGroupKey) {
+        return activeSessions.contains(botGroupKey);
     }
 
     /**
      * 세션 종료 (웬디 종료)
      */
-    public KakaoResponse endSession(String userKey) {
-        activeSessions.remove(userKey);
-        participants.remove(userKey);
-        userVoteId.remove(userKey);
-        participantDisplayNames.remove(userKey);
-        userShareUrl.remove(userKey);
-        voteCreatedAt.remove(userKey);
-        sessionStates.remove(userKey);
+    public KakaoResponse endSession(String botGroupKey) {
+        Long voteId = sessionVoteId.get(botGroupKey);
 
-        log.info("[Kakao When:D] Session ended: {}", userKey);
+        if (voteId != null) {
+            voteService.closeVote(voteId); // status = CLOSED
+            log.info("[Kakao When:D] Vote closed: voteId={}", voteId);
+        }
+
+        activeSessions.remove(botGroupKey);
+        sessionVoteId.remove(botGroupKey);
+        sessionStates.remove(botGroupKey);
+
+        log.info("[Kakao When:D] Session ended: botGroupKey={}", botGroupKey);
 
         Map<String, Object> data = new HashMap<>();
-        data.put("sessionKey", userKey);
+        data.put("botGroupKey", botGroupKey);
         data.put("state", SessionState.IDLE.name());
         data.put("active", false);
         return dataOnly(data);
@@ -132,65 +96,22 @@ public KakaoResponse endSession(String userKey) {
     /**
      * 현재 세션 상태 조회
      */
-    public SessionState getSessionState(String userKey) {
-        return sessionStates.getOrDefault(userKey, SessionState.IDLE);
+    public SessionState getSessionState(String botGroupKey) {
+        return sessionStates.getOrDefault(botGroupKey, SessionState.IDLE);
     }
 
-    // ========== 참석자 관리 ==========
-
-    /**
-     * 참석자 추가 (botUserKey 리스트 입력)
-     **/
-    public KakaoResponse addParticipants(String userKey, String input) {
-        // input: 컨트롤러에서 botUserKey 목록을 ","로 정규화하여 전달한다고 가정
-        String raw = Optional.ofNullable(input).orElse("");
-
-        List<String> keys = Arrays.stream(raw.split(","))
-                .map(String::trim)
-                .filter(s -> !s.isEmpty())
-                .distinct()
-                .collect(Collectors.toList());
-
-        if (keys.isEmpty()) {
-            Map<String, Object> data = new HashMap<>();
-            data.put("sessionKey", userKey);
-            data.put("state", getSessionState(userKey).name());
-            data.put("participantCount", 0);
-            data.put("enabled", false);
-            return dataOnly(data);
-        }
-
-        // 표시명은 PRD 상 botUserKey만 받는 상황을 고려해 임시 생성
-        List<String> displayNames = new ArrayList<>();
-        for (int i = 0; i < keys.size(); i++) {
-            displayNames.add("참석자" + (i + 1));
-        }
-
-        participants.put(userKey, keys);
-        participantDisplayNames.put(userKey, displayNames);
-        sessionStates.put(userKey, SessionState.WAITING_WEEKS);
-
-        log.info("[Kakao When:D] Participants added: {} -> {}", userKey, keys);
-
-        Map<String, Object> data = new HashMap<>();
-        data.put("sessionKey", userKey);
-        data.put("state", SessionState.WAITING_WEEKS.name());
-        data.put("participantCount", keys.size());
-        data.put("botUserKeys", keys);
-
-        data.put("participantDisplayNames", displayNames);
-        return dataOnly(data);
-    }
+    // 참석자 관리 섹션 삭제됨
 
     // ========== 투표 생성 ==========
 
     /**
-     * 투표 생성 (주차 선택 후)
+     * 투표 생성 (주차/기간 선택 후)
+     * - 사용자 입력(weeks)을 기준으로 서버에서 날짜 범위를 계산합니다.
+     * - Vote 엔티티에 botGroupKey를 포함하여 저장해야 합니다. (Vote.botGroupKey, status=ACTIVE)
+     * - 사용자에게는 고정 리다이렉트 엔드포인트(/open-vote) 링크를 제공합니다.
      */
-    public KakaoResponse createVote(String userKey, int weeks) {
-        voteCreatedAt.put(userKey, LocalDateTime.now());
-
-        // 1. 날짜 범위 계산
+    public KakaoResponse createVote(String botGroupKey, int weeks) {
+        // 날짜 범위 계산
         LocalDate today = LocalDate.now();
         LocalDate startDate;
         LocalDate endDate;
@@ -205,38 +126,35 @@ public KakaoResponse createVote(String userKey, int weeks) {
             endDate = startDate.plusDays(6);
         }
 
-        // 2. 참여자 표시명 리스트
-        List<String> participantNames = participantDisplayNames.getOrDefault(userKey, List.of());
+        // 세션 상태 정리
+        activeSessions.add(botGroupKey);
+        sessionStates.put(botGroupKey, SessionState.VOTE_CREATED);
 
-        // 3. 투표 생성
         CreateVoteReq req = new CreateVoteReq(
                 "카카오 투표",
                 startDate,
                 endDate,
-                participantNames.isEmpty() ? null : participantNames
+                null
         );
 
-        VoteSummary summary = voteService.create(req);
+        VoteSummary summary = voteService.create(req, botGroupKey);
         Long voteId = summary.id();
-        String shareUrl = summary.shareUrl();
 
-        userVoteId.put(userKey, voteId);
-        userShareUrl.put(userKey, shareUrl);
-        sessionStates.put(userKey, SessionState.VOTE_CREATED);
+        // 고정 리다이렉트 링크 (카카오가 botGroupKey/botUserKey/appUserId를 자동 append)
+        String redirectUrl = "/open-vote";
 
-        log.info("[Kakao When:D] Vote created: userKey={}, voteId={}, weeks={}", userKey, voteId, weeks);
+        sessionVoteId.put(botGroupKey, voteId);
 
-        String weekLabel = weeks == 0 ? "이번 주" : weeks + "주 뒤";
+        log.info("[Kakao When:D] Vote created: botGroupKey={}, voteId={}, startDate={}, endDate={}, weeks={}",
+                botGroupKey, voteId, startDate, endDate, weeks);
 
         Map<String, Object> data = new HashMap<>();
+        data.put("botGroupKey", botGroupKey);
         data.put("voteId", voteId);
-        data.put("shareUrl", shareUrl);
-        data.put("weekLabel", weekLabel);
+        data.put("redirectUrl", redirectUrl);
         data.put("startDate", startDate.toString());
         data.put("endDate", endDate.toString());
-        data.put("participants", participantNames);
-
-        data.put("sessionKey", userKey);
+        data.put("weeks", weeks);
         data.put("state", SessionState.VOTE_CREATED.name());
         return dataOnly(data);
     }
@@ -245,16 +163,25 @@ public KakaoResponse createVote(String userKey, int weeks) {
      * 주차 파싱 (0 = 이번 주, 1~6 = n주 뒤)
      */
     public Integer parseWeeks(String input) {
-        if (input.contains("이번")) return 0;
-        if (input.contains("1주")) return 1;
-        if (input.contains("2주")) return 2;
-        if (input.contains("3주")) return 3;
-        if (input.contains("4주")) return 4;
-        if (input.contains("5주")) return 5;
-        if (input.contains("6주")) return 6;
-
-        // 숫자만 추출
-        String numbers = input.replaceAll("[^0-9]", "");
+        if (input == null || input.isBlank()) return null;
+
+        String s = input.trim();
+
+        // 자주 쓰는 자연어 표현
+        if (s.contains("이번")) return 0;
+        if (s.contains("다다음")) return 2;
+        if (s.contains("다음")) return 1;
+
+        // 명시적 "n주" 표현
+        if (s.contains("1주")) return 1;
+        if (s.contains("2주")) return 2;
+        if (s.contains("3주")) return 3;
+        if (s.contains("4주")) return 4;
+        if (s.contains("5주")) return 5;
+        if (s.contains("6주")) return 6;
+
+        // 숫자만 추출 (예: "2주 후", "3주뒤" 등)
+        String numbers = s.replaceAll("[^0-9]", "");
         if (!numbers.isEmpty()) {
             try {
                 int weeks = Integer.parseInt(numbers);
@@ -269,9 +196,9 @@ public Integer parseWeeks(String input) {
     /**
      * 투표 결과 조회
      */
-    public KakaoResponse getVoteResult(String userKey) {
-        Long voteId = userVoteId.get(userKey);
-        String shareUrl = userShareUrl.get(userKey);
+    public KakaoResponse getVoteResult(String botGroupKey) {
+        Long voteId = sessionVoteId.get(botGroupKey);
+        String redirectUrl = "/open-vote";
 
         if (voteId == null) {
             return textOnly("""
@@ -287,13 +214,10 @@ public KakaoResponse getVoteResult(String userKey) {
             StringBuilder sb = new StringBuilder();
             sb.append("웬디가 투표 현황을 공유드려요! :D\n\n");
             sb.append("엥 아직 아무도 투표를 안 했네요 :(\n");
-            if (shareUrl != null && !shareUrl.isBlank()) {
-                sb.append("\n투표하러 가기: ").append(shareUrl);
-            }
+            sb.append("\n투표하러 가기: ").append(redirectUrl);
             return textOnly(sb.toString().trim());
         }
 
-
         // 1~3순위만 출력 (없는 순위는 생략)
         List<RankingRes> top3 = result.rankings().stream()
                 .filter(r -> r.rank() != null)
@@ -303,12 +227,7 @@ public KakaoResponse getVoteResult(String userKey) {
 
         StringBuilder sb = new StringBuilder();
         sb.append("웬디가 투표 현황을 공유드려요! :D\n");
-
-        if (shareUrl != null && !shareUrl.isBlank()) {
-            sb.append("\n투표하러 가기: ").append(shareUrl).append("\n\n");
-        } else {
-            sb.append("\n투표 링크가 준비되지 않았어요 😢\n\n");
-        }
+        sb.append("\n투표하러 가기: ").append(redirectUrl).append("\n\n");
 
         for (RankingRes rank : top3) {
             String periodLabel = "LUNCH".equals(rank.period()) ? "점심" : "저녁";
@@ -337,18 +256,21 @@ public KakaoResponse getVoteResult(String userKey) {
     }
 
     /**
-     * 재투표 (동일 참석자로 새 투표 생성)
+     * 재투표 (세션 상태를 WAITING_WEEKS로 되돌리고 voteId를 제거)
      */
-    public KakaoResponse revote(String userKey) {
-        if (!userVoteId.containsKey(userKey)) {
+    public KakaoResponse revote(String botGroupKey) {
+        if (!sessionVoteId.containsKey(botGroupKey)) {
+            activeSessions.add(botGroupKey);
+            sessionStates.put(botGroupKey, SessionState.WAITING_WEEKS);
             Map<String, Object> data = new HashMap<>();
             data.put("hasVote", false);
-            data.put("state", getSessionState(userKey).name());
+            data.put("state", SessionState.WAITING_WEEKS.name());
             return dataOnly(data);
         }
 
-        userVoteId.remove(userKey);
-        sessionStates.put(userKey, SessionState.WAITING_WEEKS);
+        sessionVoteId.remove(botGroupKey);
+        activeSessions.add(botGroupKey);
+        sessionStates.put(botGroupKey, SessionState.WAITING_WEEKS);
 
         Map<String, Object> data = new HashMap<>();
         data.put("hasVote", true);
@@ -368,89 +290,21 @@ public KakaoResponse help() {
     /**
      * 알 수 없는 입력 처리
      */
-    public KakaoResponse unknownInput(String userKey) {
-        SessionState state = getSessionState(userKey);
+    public KakaoResponse unknownInput(String botGroupKey) {
+        SessionState state = getSessionState(botGroupKey);
         Map<String, Object> data = new HashMap<>();
         data.put("state", state.name());
-        String shareUrl = userShareUrl.get(userKey);
-        if (shareUrl != null) {
-            data.put("shareUrl", shareUrl);
-        }
-        Long voteId = userVoteId.get(userKey);
+        Long voteId = sessionVoteId.get(botGroupKey);
         if (voteId != null) {
             data.put("voteId", voteId);
+            data.put("redirectUrl", "/open-vote");
         }
+        data.put("botGroupKey", botGroupKey);
         return dataOnly(data);
     }
 
-    // ========== 그룹챗 지원 메서드 ==========
-
-    /**
-     * 세션 시작 (그룹챗용)
-     */
-    public KakaoResponse startSession(String sessionKey, String botGroupKey) {
-        KakaoResponse response = startSession(sessionKey);
-
-        // 그룹챗인 경우 botGroupKey 추가 저장
-        if (botGroupKey != null && !botGroupKey.isBlank()) {
-            log.info("[Kakao When:D] Group session started: sessionKey={}, botGroupKey={}", sessionKey, botGroupKey);
-        }
-
-        return response;
-    }
-
-    /**
-     * 투표 생성 (그룹챗용)
-     */
-    public KakaoResponse createVote(String sessionKey, int weeks, String botGroupKey) {
-        KakaoResponse response = createVote(sessionKey, weeks);
-
-        // 그룹챗인 경우 botGroupKey -> voteId 매핑 저장
-        if (botGroupKey != null && !botGroupKey.isBlank()) {
-            Long voteId = sessionVoteId.get(sessionKey);
-            if (voteId != null) {
-                groupVoteId.put(botGroupKey, voteId);
-                voteIdToGroupKey.put(voteId, botGroupKey);
-                log.info("[Kakao When:D] Group vote mapping: botGroupKey={}, voteId={}", botGroupKey, voteId);
-            }
-        }
-
-        return response;
-    }
-
-    /**
-     * botGroupKey로 voteId 조회
-     */
     public Long getVoteIdByBotGroupKey(String botGroupKey) {
-        return groupVoteId.get(botGroupKey);
-    }
-
-    /**
-     * voteId로 botGroupKey 조회
-     */
-    public String getBotGroupKeyByVoteId(Long voteId) {
-        return voteIdToGroupKey.get(voteId);
-    }
-
-    /**
-     * sessionKey로 voteId 조회
-     */
-    public Long getVoteIdBySessionKey(String sessionKey) {
-        return sessionVoteId.get(sessionKey);
-    }
-
-    /**
-     * sessionKey로 shareUrl 조회
-     */
-    public String getShareUrlBySessionKey(String sessionKey) {
-        return sessionShareUrl.get(sessionKey);
-    }
-
-    /**
-     * sessionKey로 voteCreatedAt 조회
-     */
-    public LocalDateTime getVoteCreatedAtBySessionKey(String sessionKey) {
-        return voteCreatedAt.get(sessionKey);
+        return sessionVoteId.get(botGroupKey);
     }
 
     // ========== 헬퍼 메서드 ==========
@@ -479,15 +333,4 @@ private KakaoResponse textOnly(String text) {
                 .build();
     }
 
-    private String getDayLabel(DayOfWeek dayOfWeek) {
-        return switch (dayOfWeek) {
-            case MONDAY -> "월";
-            case TUESDAY -> "화";
-            case WEDNESDAY -> "수";
-            case THURSDAY -> "목";
-            case FRIDAY -> "금";
-            case SATURDAY -> "토";
-            case SUNDAY -> "일";
-        };
-    }
 }
\ No newline at end of file
diff --git a/src/main/java/com/workingdead/meet/controller/ParticipantController.java b/src/main/java/com/workingdead/meet/controller/ParticipantController.java
index 0b4217e..62d4536 100644
--- a/src/main/java/com/workingdead/meet/controller/ParticipantController.java
+++ b/src/main/java/com/workingdead/meet/controller/ParticipantController.java
@@ -43,19 +43,18 @@ public ParticipantController(
     // 0.2 참여자 추가/삭제
     @Operation(
             summary = "참여자 추가",
-            description = "특정 투표에 새로운 참여자를 추가합니다. displayName을 기반으로 참여자 칩이 생성됩니다."
-    )
+            description = "PRD: 카카오가 전달한 botUserKey(voteUserKey)로 참여자를 식별합니다. 해당 voteId에 (botUserKey) 참가자가 없으면 생성하고, displayName은 웹에서 사용자가 입력하는 값이라 비어 있을 수 있으며 전달되면 저장/갱신합니다."    )
     @ApiResponses({
             @ApiResponse(responseCode = "200", description = "참여자 추가 성공",
                     content = @Content(schema = @Schema(implementation = ParticipantDtos.ParticipantRes.class))),
-            @ApiResponse(responseCode = "400", description = "잘못된 요청 (displayName이 비어있는 경우)", content = @Content),
+            @ApiResponse(responseCode = "400", description = "잘못된 요청 (botUserKey가 비어있는 경우)", content = @Content),
             @ApiResponse(responseCode = "404", description = "투표를 찾을 수 없음", content = @Content)
     })
     @PostMapping("/votes/{voteId}/participants")
     public ResponseEntity<ParticipantDtos.ParticipantRes> add(
-            @PathVariable Long voteId, 
-            @RequestBody @Valid ParticipantDtos.CreateParticipantReq req) {
-        var res = participantService.add(voteId, req.displayName());
+            @PathVariable Long voteId,
+            @RequestBody ParticipantDtos.CreateParticipantReq req) {
+        var res = participantService.add(voteId, req.botUserKey(), req.displayName());
         return ResponseEntity.ok(res);
     }
 
diff --git a/src/main/java/com/workingdead/meet/controller/RedirectController.java b/src/main/java/com/workingdead/meet/controller/RedirectController.java
new file mode 100644
index 0000000..37bdf3c
--- /dev/null
+++ b/src/main/java/com/workingdead/meet/controller/RedirectController.java
@@ -0,0 +1,41 @@
+package com.workingdead.meet.controller;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import com.workingdead.meet.entity.Vote;
+import com.workingdead.meet.service.VoteService;
+import java.net.URI;
+
+import java.net.URLEncoder;
+import lombok.RequiredArgsConstructor;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequiredArgsConstructor
+public class RedirectController {
+
+    private final VoteService voteService;
+
+    /**
+     * 카카오 챗봇 버튼 클릭 시 호출되는 리다이렉트 엔드포인트
+     * - botGroupKey(채팅방 ID)를 기준으로 활성 투표를 조회
+     * - 실제 투표 웹 페이지로 302 Redirect 수행
+     */
+    @GetMapping("/open-vote")
+    public ResponseEntity<Void> openVote(
+            @RequestParam String botGroupKey,
+            @RequestParam String botUserKey
+    ) {
+        // 1) 현재 ACTIVE 투표 찾기
+        Vote vote = voteService.findActiveVoteByBotGroupKey(botGroupKey);
+
+        // 2) 웹으로 redirect (web 라우트: /{shareCode})
+        URI target = URI.create("https://whendy.netlify.app/" + vote.getCode()
+                + "?botUserKey=" + URLEncoder.encode(botUserKey, UTF_8)
+        );
+        return ResponseEntity.status(302).location(target).build();
+    }
+}
diff --git a/src/main/java/com/workingdead/meet/dto/ParticipantDtos.java b/src/main/java/com/workingdead/meet/dto/ParticipantDtos.java
index fcd569d..56e0473 100644
--- a/src/main/java/com/workingdead/meet/dto/ParticipantDtos.java
+++ b/src/main/java/com/workingdead/meet/dto/ParticipantDtos.java
@@ -7,7 +7,7 @@
 
 
 public class ParticipantDtos {
-    public record CreateParticipantReq(@NotBlank String displayName) {}
+    public record CreateParticipantReq(@NotBlank String botUserKey, String displayName) {}
     public record UpdateParticipantReq(String displayName) {}
     public record ParticipantRes(Long id, String displayName, boolean loggedIn // 로그인 상태
         ) {}
diff --git a/src/main/java/com/workingdead/meet/entity/Participant.java b/src/main/java/com/workingdead/meet/entity/Participant.java
index 61fcd35..2f6ae75 100644
--- a/src/main/java/com/workingdead/meet/entity/Participant.java
+++ b/src/main/java/com/workingdead/meet/entity/Participant.java
@@ -13,8 +13,15 @@
 @AllArgsConstructor 
 @Builder
 @Entity
-@Table(name = "participant")
-public class Participant {
+@Table(
+        name = "participant",
+        uniqueConstraints = {
+                @UniqueConstraint(
+                        name = "uk_participant_vote_bot_user",
+                        columnNames = {"vote_id", "bot_user_key"}
+                )
+        }
+)public class Participant {
     
     @Id 
     @GeneratedValue(strategy = GenerationType.IDENTITY)
@@ -24,13 +31,16 @@ public class Participant {
     @JoinColumn(name = "vote_id", nullable = false)
     private Vote vote;
 
-    @Column(name = "display_name", nullable = false)
+    @Column(name = "display_name")
     private String displayName;
 
+    @Column(name = "bot_user_key", nullable = false)
+    private String botUserKey;
+
     @Column(name = "submitted_at")
     private LocalDateTime submittedAt;
     
-    private Boolean submitted;
+    private Boolean submitted = false;
     
     // 일정 선택 정보
     @OneToMany(mappedBy = "participant", cascade = CascadeType.ALL, orphanRemoval = true)
@@ -43,8 +53,9 @@ public class Participant {
     private List<PriorityPreference> priorities = new ArrayList<>();
     
     // 편의 생성자
-    public Participant(Vote vote, String displayName) {
+    public Participant(Vote vote, String displayName, String botUserKey) {
         this.vote = vote;
         this.displayName = displayName;
+        this.botUserKey = botUserKey;
     }
 }
\ No newline at end of file
diff --git a/src/main/java/com/workingdead/meet/entity/Vote.java b/src/main/java/com/workingdead/meet/entity/Vote.java
index 9f8e49d..a861977 100644
--- a/src/main/java/com/workingdead/meet/entity/Vote.java
+++ b/src/main/java/com/workingdead/meet/entity/Vote.java
@@ -20,6 +20,13 @@ public class Vote {
     @Column(unique = true, nullable = false, updatable = false)
     private String code; // 공유용 짧은 코드 (링크)
 
+    @Column(nullable = false)
+    private String botGroupKey; // 카카오톡 채팅방 ID
+
+    @Enumerated(EnumType.STRING)
+    @Column(nullable = false)
+    private VoteStatus status  = VoteStatus.ACTIVE;
+
     private LocalDate startDate; // 선택 범위 시작
     private LocalDate endDate; // 선택 범위 끝
 
@@ -37,4 +44,14 @@ public Vote(String name, String code) {
 
     // getters/setters
     public void setDateRange(LocalDate start, LocalDate end) { this.startDate = start; this.endDate = end; }
+
+
+    public enum VoteStatus {
+        ACTIVE,
+        CLOSED
+    }
+
+    public void close() {
+        this.status = VoteStatus.CLOSED;
+    }
 }
diff --git a/src/main/java/com/workingdead/meet/repository/ParticipantRepository.java b/src/main/java/com/workingdead/meet/repository/ParticipantRepository.java
index cd8650b..1677d1e 100644
--- a/src/main/java/com/workingdead/meet/repository/ParticipantRepository.java
+++ b/src/main/java/com/workingdead/meet/repository/ParticipantRepository.java
@@ -1,6 +1,7 @@
 package com.workingdead.meet.repository;
 
 import com.workingdead.meet.entity.Participant;
+import java.util.Optional;
 import org.springframework.data.jpa.repository.JpaRepository;
 
 import java.util.List;
@@ -9,4 +10,6 @@
 
 public interface ParticipantRepository extends JpaRepository<Participant, Long> {
     List<Participant> findByVoteId(Long voteId);
+
+    Optional<Participant> findByVoteIdAndBotUserKey(Long voteId, String botUserKey);
 }
diff --git a/src/main/java/com/workingdead/meet/repository/VoteRepository.java b/src/main/java/com/workingdead/meet/repository/VoteRepository.java
index 0e62d8f..bfa0f13 100644
--- a/src/main/java/com/workingdead/meet/repository/VoteRepository.java
+++ b/src/main/java/com/workingdead/meet/repository/VoteRepository.java
@@ -7,4 +7,5 @@
 
 public interface VoteRepository extends JpaRepository<Vote, Long> {
     Optional<Vote> findByCode(String code);
+    Optional<Vote> findTopByBotGroupKeyAndStatusOrderByCreatedAtDesc(String botGroupKey, Vote.VoteStatus status);
 }
diff --git a/src/main/java/com/workingdead/meet/service/ParticipantService.java b/src/main/java/com/workingdead/meet/service/ParticipantService.java
index 1eb06cc..df32706 100644
--- a/src/main/java/com/workingdead/meet/service/ParticipantService.java
+++ b/src/main/java/com/workingdead/meet/service/ParticipantService.java
@@ -4,13 +4,12 @@
 import com.workingdead.meet.entity.*;
 import com.workingdead.meet.repository.*;
 import java.util.Objects;
+import java.util.Optional;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
-import java.security.SecureRandom;
 import java.util.NoSuchElementException;
 import java.util.List;
-import java.util.ArrayList;
 import java.util.stream.Collectors;
 
 import org.springframework.web.server.ResponseStatusException;
@@ -24,8 +23,6 @@ public class ParticipantService {
     private final VoteRepository voteRepo;
     private final ParticipantSelectionRepository selectionRepo;      // 추가!
     private final PriorityPreferenceRepository priorityRepo;         // 추가!
-    private static final String CODE_ALPHABET = "abcdefghijkmnopqrstuvwxyz23456789";
-    private final SecureRandom rnd = new SecureRandom();
 
     // 생성자 수정
     public ParticipantService(
@@ -39,14 +36,56 @@ public ParticipantService(
         this.priorityRepo = priorityRepo;                            // 추가!
     }
 
-    public ParticipantDtos.ParticipantRes add(Long voteId, String displayName) {
-        Vote v = voteRepo.findById(voteId)
-                        .orElseThrow(() -> new NoSuchElementException("vote not found"));
-        Participant p = new Participant(v, displayName);
-        participantRepo.save(p);
-        return new ParticipantDtos.ParticipantRes(p.getId(), p.getDisplayName(), false);
+    /**
+     * (PRD) 참가자 upsert
+     * - 식별은 (voteId, botUserKey)
+     * - displayName은 웹에서 사용자가 입력하므로 처음에는 비어 있을 수 있음
+     */
+    public ParticipantDtos.ParticipantRes add(Long voteId, String botUserKey, String displayName) {
+        Participant participant = getOrCreateByVoteAndBotUserKey(voteId, botUserKey);
+
+        // displayName은 웹에서 입력/수정될 수 있으므로, 값이 들어오면 항상 최신으로 반영합니다.
+        if (displayName != null && !displayName.isBlank()) {
+            String trimmed = displayName.trim();
+            if (!Objects.equals(trimmed, participant.getDisplayName())) {
+                participant.setDisplayName(trimmed);
+            }
+        }
+
+        Participant saved = participantRepo.save(participant);
+        return new ParticipantDtos.ParticipantRes(
+                saved.getId(),
+                saved.getDisplayName(),
+                Boolean.TRUE.equals(saved.getSubmitted())
+        );
+    }
+
+    /**
+     * (voteId, botUserKey)로 Participant 확보
+     * - 없으면 생성하며, displayName은 이후 웹에서 업데이트될 수 있음
+     */
+    private Participant getOrCreateByVoteAndBotUserKey(Long voteId, String botUserKey) {
+
+        if (voteId == null) {
+            throw new IllegalArgumentException("voteId is required");
+        }
+
+        if (botUserKey == null || botUserKey.isBlank()) {
+            throw new IllegalArgumentException("botUserKey is required");
+        }
+
+        Optional<Participant> existing = participantRepo.findByVoteIdAndBotUserKey(voteId, botUserKey);
+        if (existing.isPresent()) {
+            return existing.get();
+        }
+
+        Vote vote = voteRepo.findById(voteId)
+                .orElseThrow(() -> new NoSuchElementException("vote not found"));
+
+        return new Participant(vote, null, botUserKey);
     }
 
+
     public ParticipantDtos.ParticipantRes updateParticipant(Long participantId, ParticipantDtos.UpdateParticipantReq request) {
         Participant participant = participantRepo.findById(participantId)
                 .orElseThrow(() -> new NoSuchElementException("Participant not found"));
@@ -61,7 +100,7 @@ public ParticipantDtos.ParticipantRes updateParticipant(Long participantId, Part
         return new ParticipantDtos.ParticipantRes(
                 saved.getId(),
                 saved.getDisplayName(),
-                false
+                Boolean.TRUE.equals(saved.getSubmitted())
         );
     }
 
@@ -104,7 +143,7 @@ public List<ParticipantDtos.ParticipantRes> getParticipantsForVote(Long voteId)
                 .map(p -> new ParticipantDtos.ParticipantRes(
                         p.getId(),
                         p.getDisplayName(),
-                        false 
+                        Boolean.TRUE.equals(p.getSubmitted())
                 ))
                 .collect(Collectors.toList());
     }
@@ -201,12 +240,6 @@ public ParticipantDtos.ParticipantScheduleRes submitSchedule(
                 saved.getSubmitted()
         );
     }
-    
-    private String genCode(int len) {
-        StringBuilder sb = new StringBuilder(len);
-        for (int i=0;i<len;i++) sb.append(CODE_ALPHABET.charAt(rnd.nextInt(CODE_ALPHABET.length())));
-        return sb.toString();
-    }
 
     /**
      * 특정 참여자의 선택한 일정과 우선순위 조회 (participantId만 사용)
diff --git a/src/main/java/com/workingdead/meet/service/VoteService.java b/src/main/java/com/workingdead/meet/service/VoteService.java
index 7fa2c1a..d302227 100644
--- a/src/main/java/com/workingdead/meet/service/VoteService.java
+++ b/src/main/java/com/workingdead/meet/service/VoteService.java
@@ -2,8 +2,8 @@
 
 import com.workingdead.meet.dto.ParticipantDtos;
 import com.workingdead.meet.dto.VoteDtos;
-import com.workingdead.meet.entity.Participant;
 import com.workingdead.meet.entity.Vote;
+import com.workingdead.meet.entity.Vote.VoteStatus;
 import com.workingdead.meet.repository.VoteRepository;
 import jakarta.transaction.Transactional;
 import org.springframework.beans.factory.annotation.Value;
@@ -27,27 +27,42 @@ public VoteService(VoteRepository voteRepo, @Value("${app.base-url:http://whendy
     }
 
 
+    /**
+     * @deprecated PRD 기준으로 Vote.botGroupKey가 NOT NULL 입니다.
+     *             카카오 플로우에서는 반드시 create(req, botGroupKey) 를 사용하세요.
+     */
+    @Deprecated
     public VoteDtos.VoteSummary create(VoteDtos.CreateVoteReq req) {
-        //1. Vote c
+        throw new UnsupportedOperationException("Vote.botGroupKey is required. Use create(req, botGroupKey).");
+    }
+
+    /**
+     * 투표 생성 (카카오 그룹챗 전용)
+     * - botGroupKey를 Vote에 저장 (NOT NULL)
+     * - 같은 botGroupKey에 ACTIVE 투표가 이미 있으면 CLOSED로 종료 처리
+     */
+    public VoteDtos.VoteSummary create(VoteDtos.CreateVoteReq req, String botGroupKey) {
+        if (botGroupKey == null || botGroupKey.isBlank()) {
+            throw new IllegalArgumentException("botGroupKey must not be blank");
+        }
+
+        // 0) 기존 ACTIVE 투표가 있으면 종료 (status 활용)
+        voteRepo.findTopByBotGroupKeyAndStatusOrderByCreatedAtDesc(botGroupKey, VoteStatus.ACTIVE)
+                .ifPresent(Vote::close);
+
+        // 1) Vote 생성
         String code = genCode(8);
         Vote v = new Vote(req.name(), code);
 
-        // 2. 날짜 범위 설정 (있으면)
+        // botGroupKey 세팅 (Vote.botGroupKey NOT NULL)
+        v.setBotGroupKey(botGroupKey);
+
+        // 2) 날짜 범위 설정 (있으면)
         if (req.startDate() != null && req.endDate() != null) {
             if (req.endDate().isBefore(req.startDate())) {
                 throw new IllegalArgumentException("endDate must be >= startDate");
             }
             v.setDateRange(req.startDate(), req.endDate());
-
-            // 3. 참여자 추가 (있으면)
-            if (req.participantNames() != null && !req.participantNames().isEmpty()) {
-                for (String name : req.participantNames()) {
-                    if (name != null && !name.isBlank()) {
-                        Participant p = new Participant(v, name.trim());
-                        v.getParticipants().add(p);
-                    }
-                }
-            }
         }
 
         voteRepo.save(v);
@@ -82,11 +97,29 @@ public VoteDtos.VoteDetail update(Long id, VoteDtos.UpdateVoteReq req) {
         return toDetail(v);
     }
 
+    @Transactional
+    public void closeVote(Long voteId) {
+        Vote vote = voteRepo.findById(voteId)
+                .orElseThrow(() -> new NoSuchElementException("vote not found"));
+        vote.close(); // status = CLOSED
+    }
+
 
     public void delete(Long id) {
         voteRepo.deleteById(id);
     }
 
+    /**
+     * 채팅방(botGroupKey) 기준으로 "현재 활성" 투표를 찾아야 할 때 사용합니다.
+     */
+    public Vote findActiveVoteByBotGroupKey(String botGroupKey) {
+        return voteRepo
+                .findTopByBotGroupKeyAndStatusOrderByCreatedAtDesc(
+                        botGroupKey, VoteStatus.ACTIVE
+                )
+                .orElseThrow(() -> new NoSuchElementException("active vote not found"));
+    }
+
 
     private String genCode(int len) {
         StringBuilder sb = new StringBuilder(len);
@@ -99,7 +132,7 @@ private String genCode(int len) {
 
     private VoteDtos.VoteSummary toSummary(Vote v) {
         String admin = baseUrl + "/admin/votes/" + v.getId();
-        String share = baseUrl + "/v/" + v.getCode();
+        String share = shareUrl(v);
         return new VoteDtos.VoteSummary(v.getId(), v.getName(), v.getCode(), admin, share, v.getStartDate(), v.getEndDate());
     }
 
@@ -111,4 +144,8 @@ private VoteDtos.VoteDetail toDetail(Vote v) {
 
         return new VoteDtos.VoteDetail(v.getId(), v.getName(), v.getCode(), v.getStartDate(), v.getEndDate(), participants);
     }
+
+    private String shareUrl(Vote v) {
+        return baseUrl + "/v/" + v.getCode();
+    }
 }
diff --git a/src/main/resources/application.yaml b/src/main/resources/application.yaml
index ecc569f..82f0f90 100644
--- a/src/main/resources/application.yaml
+++ b/src/main/resources/application.yaml
@@ -69,6 +69,6 @@ discord:
 
 kakao:
   rest-api-key: ${KAKAO_REST_API_KEY}
-  admin-key: ${KAKAO_ADMIN_KEY:}
+  event-api-key: ${KAKAO_EVENT_API_KEY:}
   channel-id: ${KAKAO_CHANNEL_ID:}
   bot-id: ${KAKAO_BOT_ID:}
\ No newline at end of file