diff --git a/helpers.go b/helpers.go
index c0bd969..4fb6cb0 100644
--- a/helpers.go
+++ b/helpers.go
@@ -154,3 +154,49 @@ func extractEventID(jsonStr string) string {
 	// get 64 characters of the id
 	return jsonStr[start : start+64]
 }
+
+func extractDTag(jsonStr string) string {
+	// look for ["d", pattern
+	start := strings.Index(jsonStr, `["d"`)
+	if start == -1 {
+		return ""
+	}
+
+	// move to the next quote
+	offset := strings.IndexRune(jsonStr[start+4:], '"')
+	start += 4 + offset + 1
+
+	// find the ending quote
+	end := strings.IndexRune(jsonStr[start:], '"')
+	if end == -1 {
+		return ""
+	}
+
+	// get the contents
+	return jsonStr[start : start+end]
+}
+
+func extractTimestamp(jsonStr string) Timestamp {
+	// look for "created_at": pattern
+	start := strings.Index(jsonStr, `"created_at"`)
+	if start == -1 {
+		return 0
+	}
+
+	// move to the next number
+	offset := strings.IndexAny(jsonStr[start+12:], "9876543210")
+	if offset == -1 {
+		return 0
+	}
+	start += 12 + offset
+
+	// find the end
+	end := strings.IndexAny(jsonStr[start:], ",} ")
+	if end == -1 {
+		return 0
+	}
+
+	// get the contents
+	ts, _ := strconv.ParseInt(jsonStr[start:start+end], 10, 64)
+	return Timestamp(ts)
+}
diff --git a/helpers_test.go b/helpers_test.go
index 1bf6fc0..e7872f5 100644
--- a/helpers_test.go
+++ b/helpers_test.go
@@ -43,4 +43,26 @@ func TestSubIdExtract(t *testing.T) {
 	}
 }
 
+func TestDTagExtract(t *testing.T) {
+	{
+		data := `["EVENT", "xxz" ,{"kind":30023,"id":"6b5988e9471fa340880a40df815befc69c901420facfb670acd8308012088f16","pubkey":"67ada8e344532cbf82f0e702472e24c7896e0e1c96235eacbaaa4b8616052171","created_at":1736909072,"tags":[["d", "balalaika"]["e","cfdf18b78527455097515545be4ccbe17e9b88f64539a566c632e405e2c0d08a","","root"],["e","f1ec9c301383be082f1860f7e24e49164d855bfab67f8e5c3ed17f6f3f867cca","","reply"],["p","1afe0c74e3d7784eba93a5e3fa554a6eeb01928d12739ae8ba4832786808e36d"],["p","8aa642e26e65072139e10db59646a89aa7538a59965aab3ed89191d71967d6c3"],["p","f4d89779148ccd245c8d50914a284fd62d97cb0fb68b797a70f24a172b522db9"],["p","18905d0a5d623ab81a98ba98c582bd5f57f2506c6b808905fc599d5a0b229b08"],["p","9a0e2043afaa056a12b8bbe77ac4c3185c0e2bc46b12aac158689144323c0e3c"],["p","45f195cffcb8c9724efc248f0507a2fb65b579dfabe7cd35398598163cab7627"]],"content":"🫡","sig":"d21aaf43963b07a3cb5f85ac8809c2b2e4dd3269195f4d810e1b7650895178fe01cf685ab3ee93f193cdde1f8d17419ff05332c6e3fc7429bbbe3d70016b8638"}]`
+		require.Equal(t, "balalaika", extractDTag(data))
+	}
+	{
+		data := `{"kind":1,"pubkey":"67ada8e344532cbf82f0e702472e24c7896e0e1c96235eacbaaa4b8616052171","created_at":1736909072,"tags":[["e","cfdf18b78527455097515545be4ccbe17e9b88f64539a566c632e405e2c0d08a","","root"],["e","f1ec9c301383be082f1860f7e24e49164d855bfab67f8e5c3ed17f6f3f867cca","","reply"],["p","1afe0c74e3d7784eba93a5e3fa554a6eeb01928d12739ae8ba4832786808e36d"],["p","8aa642e26e65072139e10db59646a89aa7538a59965aab3ed89191d71967d6c3"],["p","f4d89779148ccd245c8d50914a284fd62d97cb0fb68b797a70f24a172b522db9"],["p","18905d0a5d623ab81a98ba98c582bd5f57f2506c6b808905fc599d5a0b229b08"],["p","9a0e2043afaa056a12b8bbe77ac4c3185c0e2bc46b12aac158689144323c0e3c"],["p","45f195cffcb8c9724efc248f0507a2fb65b579dfabe7cd35398598163cab7627"]],"content":"🫡","sig":"d21aaf43963b07a3cb5f85ac8809c2b2e4dd3269195f4d810e1b7650895178fe01cf685ab3ee93f193cdde1f8d17419ff05332c6e3fc7429bbbe3d70016b8638","id":  "6b5988e9471fa340880a40df815befc69c901420facfb670acd8308012088f16" }`
+		require.Equal(t, "", extractDTag(data))
+	}
+}
+
+func TestTimestampExtract(t *testing.T) {
+	{
+		data := `["EVENT", "xxz" ,{"kind":30023,"id":"6b5988e9471fa340880a40df815befc69c901420facfb670acd8308012088f16","pubkey":"67ada8e344532cbf82f0e702472e24c7896e0e1c96235eacbaaa4b8616052171","created_at":  1736909072  ,"tags":[["d", "balalaika"]["e","cfdf18b78527455097515545be4ccbe17e9b88f64539a566c632e405e2c0d08a","","root"],["e","f1ec9c301383be082f1860f7e24e49164d855bfab67f8e5c3ed17f6f3f867cca","","reply"],["p","1afe0c74e3d7784eba93a5e3fa554a6eeb01928d12739ae8ba4832786808e36d"],["p","8aa642e26e65072139e10db59646a89aa7538a59965aab3ed89191d71967d6c3"],["p","f4d89779148ccd245c8d50914a284fd62d97cb0fb68b797a70f24a172b522db9"],["p","18905d0a5d623ab81a98ba98c582bd5f57f2506c6b808905fc599d5a0b229b08"],["p","9a0e2043afaa056a12b8bbe77ac4c3185c0e2bc46b12aac158689144323c0e3c"],["p","45f195cffcb8c9724efc248f0507a2fb65b579dfabe7cd35398598163cab7627"]],"content":"🫡","sig":"d21aaf43963b07a3cb5f85ac8809c2b2e4dd3269195f4d810e1b7650895178fe01cf685ab3ee93f193cdde1f8d17419ff05332c6e3fc7429bbbe3d70016b8638"}]`
+		require.Equal(t, Timestamp(1736909072), extractTimestamp(data))
+	}
+	{
+		data := `{"kind":1,"pubkey":"67ada8e344532cbf82f0e702472e24c7896e0e1c96235eacbaaa4b8616052171","tags":[["e","cfdf18b78527455097515545be4ccbe17e9b88f64539a566c632e405e2c0d08a","","root"],["e","f1ec9c301383be082f1860f7e24e49164d855bfab67f8e5c3ed17f6f3f867cca","","reply"],["p","1afe0c74e3d7784eba93a5e3fa554a6eeb01928d12739ae8ba4832786808e36d"],["p","8aa642e26e65072139e10db59646a89aa7538a59965aab3ed89191d71967d6c3"],["p","f4d89779148ccd245c8d50914a284fd62d97cb0fb68b797a70f24a172b522db9"],["p","18905d0a5d623ab81a98ba98c582bd5f57f2506c6b808905fc599d5a0b229b08"],["p","9a0e2043afaa056a12b8bbe77ac4c3185c0e2bc46b12aac158689144323c0e3c"],["p","45f195cffcb8c9724efc248f0507a2fb65b579dfabe7cd35398598163cab7627"]],"content":"🫡","sig":"d21aaf43963b07a3cb5f85ac8809c2b2e4dd3269195f4d810e1b7650895178fe01cf685ab3ee93f193cdde1f8d17419ff05332c6e3fc7429bbbe3d70016b8638","id":  "6b5988e9471fa340880a40df815befc69c901420facfb670acd8308012088f16" ,"created_at":01736909054}`
+		require.Equal(t, Timestamp(1736909054), extractTimestamp(data))
+	}
+}
+
 func ptr[S any](s S) *S { return &s }
diff --git a/relay.go b/relay.go
index d02d340..e38c190 100644
--- a/relay.go
+++ b/relay.go
@@ -231,9 +231,13 @@ func (r *Relay) ConnectWithTLS(ctx context.Context, tlsConfig *tls.Config) error
 			// if this is an "EVENT" we will have this preparser logic that should speed things up a little
 			// as we skip handling duplicate events
 			subid := extractSubID(message)
-			subscription, ok := r.Subscriptions.Load(subIdToSerial(subid))
-			if ok && subscription.checkDuplicate != nil {
-				if subscription.checkDuplicate(extractEventID(message[10+len(subid):]), r.URL) {
+			sub, ok := r.Subscriptions.Load(subIdToSerial(subid))
+			if ok && sub.checkDuplicate != nil {
+				if sub.checkDuplicate(extractEventID(message[10+len(subid):]), r.URL) {
+					continue
+				}
+			} else if sub.checkDuplicateReplaceable != nil {
+				if sub.checkDuplicateReplaceable(extractDTag(message), extractTimestamp(message)) {
 					continue
 				}
 			}
@@ -437,6 +441,8 @@ func (r *Relay) PrepareSubscription(ctx context.Context, filters Filters, opts .
 			label = string(o)
 		case WithCheckDuplicate:
 			sub.checkDuplicate = o
+		case WithCheckDuplicateReplaceable:
+			sub.checkDuplicateReplaceable = o
 		}
 	}
 
diff --git a/subscription.go b/subscription.go
index e6d7e1c..5c8de42 100644
--- a/subscription.go
+++ b/subscription.go
@@ -33,10 +33,14 @@ type Subscription struct {
 	// Context will be .Done() when the subscription ends
 	Context context.Context
 
-	// if it is not nil, CheckDuplicate will be called for every event received
+	// if it is not nil, checkDuplicate will be called for every event received
 	// if it returns true that event will not be processed further.
 	checkDuplicate func(id string, relay string) bool
 
+	// if it is not nil, checkDuplicateReplaceable will be called for every event received
+	// if it returns true that event will not be processed further.
+	checkDuplicateReplaceable func(d string, ts Timestamp) bool
+
 	match  func(*Event) bool // this will be either Filters.Match or Filters.MatchIgnoringTimestampConstraints
 	live   atomic.Bool
 	eosed  atomic.Bool
@@ -63,9 +67,15 @@ type WithCheckDuplicate func(id, relay string) bool
 
 func (_ WithCheckDuplicate) IsSubscriptionOption() {}
 
+// WithCheckDuplicateReplaceable sets checkDuplicateReplaceable on the subscription
+type WithCheckDuplicateReplaceable func(d string, ts Timestamp) bool
+
+func (_ WithCheckDuplicateReplaceable) IsSubscriptionOption() {}
+
 var (
 	_ SubscriptionOption = (WithLabel)("")
 	_ SubscriptionOption = (WithCheckDuplicate)(nil)
+	_ SubscriptionOption = (WithCheckDuplicateReplaceable)(nil)
 )
 
 func (sub *Subscription) start() {