diff --git a/03_source/cms_backend/prisma/schema.prisma b/03_source/cms_backend/prisma/schema.prisma
index 5bf02d3..fa8dad9 100644
--- a/03_source/cms_backend/prisma/schema.prisma
+++ b/03_source/cms_backend/prisma/schema.prisma
@@ -1291,4 +1291,5 @@ model PartyUser {
   zipCode       String    @default("")
   //
   rank          String    @default("user")
+  sex           String    @default("")
 }
diff --git a/03_source/cms_backend/prisma/seeds/partyUser.ts b/03_source/cms_backend/prisma/seeds/partyUser.ts
index fb740ed..6de0f58 100644
--- a/03_source/cms_backend/prisma/seeds/partyUser.ts
+++ b/03_source/cms_backend/prisma/seeds/partyUser.ts
@@ -58,6 +58,7 @@ async function partyUser() {
       status: STATUS[0],
       role: ROLE[0],
       isVerified: true,
+      sex: 'F',
     },
   });
 
@@ -78,6 +79,7 @@ async function partyUser() {
       isVerified: true,
       avatarUrl: 'https://images.unsplash.com/photo-1619970096024-c7b438a3b82a',
       rank: 'user',
+      sex: 'M',
     },
   });
 
@@ -112,6 +114,7 @@ async function partyUser() {
         role: ROLE[Math.floor(Math.random() * ROLE.length)],
         status: STATUS[Math.floor(Math.random() * STATUS.length)],
         isVerified: true,
+        sex: i % 2 ? 'F' : 'M',
       },
     });
   }
diff --git a/03_source/cms_backend/src/app/api/event/partyUserJoinEvent/route.ts b/03_source/cms_backend/src/app/api/event/partyUserJoinEvent/route.ts
new file mode 100644
index 0000000..dea3c06
--- /dev/null
+++ b/03_source/cms_backend/src/app/api/event/partyUserJoinEvent/route.ts
@@ -0,0 +1,58 @@
+// src/app/api/product/createEvent/route.ts
+//
+// PURPOSE:
+// create product to db
+//
+// RULES:
+// T.B.A.
+//
+
+import type { NextRequest } from 'next/server';
+
+import _ from 'lodash';
+
+import { STATUS, response, handleError } from 'src/utils/response';
+
+import { getEventItemById } from 'src/app/services/eventItem.service';
+import { getPartyUserByEmail } from 'src/app/services/party-user.service';
+
+// ----------------------------------------------------------------------
+
+/**
+ ***************************************
+ * POST - Events
+ ***************************************
+ */
+export async function POST(req: NextRequest) {
+  // logger('[Event] list', events.length);
+  const { data } = await req.json();
+  const { eventItemId, email } = data;
+
+  try {
+    const eventItem = await getEventItemById(eventItemId);
+    const partyUser = await getPartyUserByEmail(email);
+
+    if (partyUser) {
+      if (eventItem && eventItem?.joinMembers) {
+        const foundJoined = _.find(eventItem.joinMembers, { email });
+
+        if (foundJoined) {
+          console.log('user joined event already, skipping');
+        } else {
+          const { sex } = partyUser;
+          eventItem.joinMembers.push({ email, sex });
+
+          await prisma?.eventItem.update({
+            where: { id: eventItem.id },
+            data: { joinMembers: JSON.parse(JSON.stringify(eventItem.joinMembers)) },
+          });
+        }
+      }
+    }
+
+    return response({ result: 'joined' }, STATUS.OK);
+  } catch (error) {
+    console.log({ hello: 'world', data });
+    return handleError('Event - Create', error);
+  }
+}
diff --git a/03_source/cms_backend/src/app/api/event/partyUserJoinEvent/test.http b/03_source/cms_backend/src/app/api/event/partyUserJoinEvent/test.http
new file mode 100644
index 0000000..cfd5099
--- /dev/null
+++ b/03_source/cms_backend/src/app/api/event/partyUserJoinEvent/test.http
@@ -0,0 +1,13 @@
+###
+
+# username and password ok
+
+POST http://localhost:7272/api/event/partyUserJoinEvent
+content-type: application/json
+
+{
+    "data": {
+        "eventItemId": "e99f09a7-dd88-49d5-b1c8-1daf80c2d7b01",
+        "email": "alice@prisma.io"
+    }
+}
diff --git a/03_source/cms_backend/src/app/services/eventItem.service.ts b/03_source/cms_backend/src/app/services/eventItem.service.ts
index cf87b36..61f067c 100644
--- a/03_source/cms_backend/src/app/services/eventItem.service.ts
+++ b/03_source/cms_backend/src/app/services/eventItem.service.ts
@@ -47,6 +47,10 @@ async function getEvent(eventId: string): Promise<EventItem | null> {
   return prisma.eventItem.findFirst({ where: { id: eventId } });
 }
 
+async function getEventItemById(eventId: string): Promise<EventItem | null> {
+  return prisma.eventItem.findFirst({ where: { id: eventId } });
+}
+
 // async function createNewEvent(createForm: CreateEvent) {
 //   return prisma.event.create({ data: createForm });
 // }
@@ -68,4 +72,5 @@ export {
   // updateEvent,
   // deleteEvent,
   // createNewEvent,
+  getEventItemById,
 };
diff --git a/03_source/cms_backend/src/app/services/party-user.service.ts b/03_source/cms_backend/src/app/services/party-user.service.ts
index e6d1af1..db34e33 100644
--- a/03_source/cms_backend/src/app/services/party-user.service.ts
+++ b/03_source/cms_backend/src/app/services/party-user.service.ts
@@ -41,6 +41,12 @@ async function getPartyUser(partyUserId: string): Promise<PartyUser | null> {
   });
 }
 
+async function getPartyUserByEmail(email: string): Promise<PartyUser | null> {
+  return prisma.partyUser.findUnique({
+    where: { email },
+  });
+}
+
 async function getUserById(id: string): Promise<User | null> {
   return prisma.user.findFirst({ where: { id } });
 }
@@ -70,6 +76,8 @@ export {
   updatePartyUser,
   deletePartyUser,
   //
+  getPartyUserByEmail,
+  //
   type CreateUser,
   type UpdateUser,
   //
diff --git a/03_source/mobile/src/pages/EventDetail/index.tsx b/03_source/mobile/src/pages/EventDetail/index.tsx
index efc740a..a56ef27 100644
--- a/03_source/mobile/src/pages/EventDetail/index.tsx
+++ b/03_source/mobile/src/pages/EventDetail/index.tsx
@@ -73,7 +73,7 @@ interface StateProps {}
 
 interface DispatchProps {}
 
-interface EventDetailProps extends OwnProps, StateProps, DispatchProps {}
+interface PageProps extends OwnProps, StateProps, DispatchProps {}
 
 const showJoinedMembers = (joinMembers: Record<string, any>[]) => {
   const avatars = joinMembers.map((jm) => jm.avatar);
@@ -90,7 +90,7 @@ const showJoinedMembers = (joinMembers: Record<string, any>[]) => {
   );
 };
 
-const EventDetail: React.FC<EventDetailProps> = ({ event_detail }) => {
+const EventDetail: React.FC<PageProps> = ({ event_detail }) => {
   const router = useIonRouter();
 
   const [showPopover, setShowPopover] = useState(false);