diff --git a/client/identity.go b/client/identity.go
index 1978aa3..ac8fa09 100644
--- a/client/identity.go
+++ b/client/identity.go
@@ -31,6 +31,7 @@ type Identity struct {
 	OwnedDevices         PeerList             `json:"owned_devices,omitempty"`
 	StaticMtkServerPaths []InternalServerList `json:"static_mtk_server_paths,omitempty"`
 	DynamicMtkServeRules []string             `json:"dynamic_mtk_serve_rules,omitempty"`
+	InvitationTimeout    int                  `json:"invitation_timeout,omitempty"`
 	unlockedHiddenPeers  PeerList
 }
 
diff --git a/server/invitation.go b/server/invitation.go
new file mode 100644
index 0000000..3260fad
--- /dev/null
+++ b/server/invitation.go
@@ -0,0 +1,70 @@
+package server
+
+import (
+	"errors"
+	"math/rand"
+	"time"
+
+	"github.com/go-redis/redis"
+)
+
+func (r *RedisRouter) CreateInvitation(invitation []byte, timeout int, password string, serverTimeout int, urlLen int) (string, time.Time) {
+	id := r.createShortUrl(urlLen)
+	if timeout > serverTimeout {
+		timeout = serverTimeout
+	}
+	r.Client.Set("mwiv:"+id, invitation, time.Duration(timeout*1000000))
+	if len(password) > 0 {
+		r.Client.Set("mwpw:"+id, password, time.Duration(timeout*1000000))
+	}
+	return id, time.Now().Add(time.Duration(timeout * 1000000)).UTC()
+}
+
+func (r *RedisRouter) GetInvitation(id string, password string) ([]byte, error) {
+	passRequired := false
+	expectedpass, err := r.Client.Get("mwpw:" + id).Result()
+	if err != nil {
+		passRequired = false
+	} else {
+		passRequired = true
+	}
+	if passRequired && password != expectedpass {
+		return nil, errors.New("invitation get : auth failed, wrong password")
+	}
+	mwiv, err := r.Client.Get("mwiv:" + id).Result()
+	if err != nil {
+		return nil, err
+	}
+	return []byte(mwiv), nil
+}
+
+func (r *RedisRouter) AnswerInvitation(id string, timeout int, invitation []byte, serverTimeout int) time.Time {
+	if timeout > serverTimeout {
+		timeout = serverTimeout
+	}
+	r.Client.Set("mwan:"+id, invitation, time.Duration(timeout*1000000))
+	return time.Now().Add(time.Duration(timeout * 1000000)).UTC()
+}
+
+func (r *RedisRouter) GetAnswer(id string) ([]byte, error) {
+	mwan, err := r.Client.Get("mwiv:" + id).Result()
+	if err != nil {
+		return nil, err
+	}
+	return []byte(mwan), nil
+}
+
+func (r *RedisRouter) createShortUrl(length int) string {
+	url := ""
+	alphabet := "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+	// for not in redis
+	for {
+		for i := 1; i <= length; i++ {
+			url += string(alphabet[rand.Intn(61)])
+		}
+		if r.Client.Get("mwiv:"+url).Err() == redis.Nil {
+			break
+		}
+	}
+	return url
+}