diff --git a/core/connection.go b/core/connection.go
index b20a954..78f44bf 100644
--- a/core/connection.go
+++ b/core/connection.go
@@ -6,6 +6,7 @@ import (
 
 	"github.com/gorilla/websocket"
 	"go.mongodb.org/mongo-driver/bson/primitive"
+	"repositories.action2quare.com/ayo/gocommon"
 	"repositories.action2quare.com/ayo/gocommon/wshandler"
 )
 
@@ -18,6 +19,7 @@ type connWithFriends struct {
 type connections struct {
 	connLock sync.Mutex
 	conns    map[primitive.ObjectID]*connWithFriends
+	redison  *gocommon.RedisonHandler
 }
 
 func (cs *connections) new(accid primitive.ObjectID, conn *websocket.Conn) {
@@ -93,14 +95,17 @@ func (cs *connections) writeMessage(acc primitive.ObjectID, src any) {
 
 func (cs *connections) ClientConnected(conn *websocket.Conn, callby *wshandler.Sender) {
 	cs.new(callby.Accid, conn)
+	cs.redison.JSONSet(callby.Accid.Hex(), "$", map[string]any{}, gocommon.RedisonSetOptionNX)
 }
 
 func (cs *connections) ClientDisconnected(msg string, callby *wshandler.Sender) {
+	cs.redison.JSONDel(callby.Accid.Hex(), "$")
 	cs.delete(callby.Accid)
 }
 
-func makeConnections() *connections {
+func makeConnections(redison *gocommon.RedisonHandler) *connections {
 	return &connections{
-		conns: make(map[primitive.ObjectID]*connWithFriends),
+		conns:   make(map[primitive.ObjectID]*connWithFriends),
+		redison: redison,
 	}
 }
diff --git a/core/invitation.go b/core/invitation.go
index 7e2948c..6d51dd6 100644
--- a/core/invitation.go
+++ b/core/invitation.go
@@ -33,6 +33,11 @@ type invitationDoc struct {
 	Blocked   bool               `bson:"blocked,omitempty" json:"-"` // From은 To에 의해 차단된 상태를 표시
 }
 
+type sneakpeekDoc struct {
+	From primitive.ObjectID `bson:"from,omitempty" json:"-"`
+	To   primitive.ObjectID `bson:"to,omitempty" json:"-"`
+}
+
 func init() {
 	gob.Register([]invitationDoc{})
 }
@@ -226,6 +231,36 @@ func (iv *invitation) Trim(ctx wshandler.ApiCallContext) {
 	}
 }
 
+func (iv *invitation) SneakPeekTarget(w http.ResponseWriter, r *http.Request) {
+	var ivdoc sneakpeekDoc
+
+	if err := gocommon.MakeDecoder(r).Decode(&ivdoc); err != nil {
+		logger.Println("InviteAsFriend failed:", err)
+		w.WriteHeader(http.StatusBadRequest)
+		return
+	}
+
+	// ivdoc.To가 invdoc.From을 차단했으면 offline으로 표시
+	exists, err := iv.mongoClient.Exists(block_collection_name, bson.M{"_id": combineObjectID(ivdoc.To, ivdoc.From)})
+	if err != nil {
+		logger.Println("InviteAsFriend failed:", err)
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	enc := gocommon.MakeEncoder(w, r)
+	if exists {
+		enc.Encode("offline")
+	} else {
+		exists, _ := iv.redison.Exists(iv.redison.Context(), ivdoc.To.Hex()).Result()
+		if exists == 0 {
+			enc.Encode("offline")
+		} else {
+			enc.Encode("online")
+		}
+	}
+}
+
 func (iv *invitation) InviteAsFriend(w http.ResponseWriter, r *http.Request) {
 	// 내 현재 친구 숫자 + 내가 보낸 초대 숫자가 FriendsMax를 넘을 수 없다.
 	// TODO : 이미 친구면 초대 불가
diff --git a/core/social.go b/core/social.go
index e540dfb..a2760da 100644
--- a/core/social.go
+++ b/core/social.go
@@ -80,7 +80,7 @@ func (so *Social) prepare(ctx context.Context) error {
 
 	so.redison = gocommon.NewRedisonHandler(redisClient.Context(), redisClient)
 
-	connections := makeConnections()
+	connections := makeConnections(so.redison)
 	so.wsh.AddHandler(wshandler.MakeWebsocketApiHandler(connections, "social"))
 	so.httpApiBorker.AddHandler(gocommon.MakeHttpApiHandler(connections, "social"))