diff --git a/go.sum b/go.sum
index 3ef89fb..55ced9e 100644
--- a/go.sum
+++ b/go.sum
@@ -17,8 +17,8 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/fiatjaf/bip340 v1.0.0 h1:mpwbm+0KC9BXB/7/pnac4e4N1TiuppyEVXxtVAXj75k=
 github.com/fiatjaf/bip340 v1.0.0/go.mod h1:MxAz+5FQUTW4OT2gnCBC6Our486wmqf72ykZIrh7+is=
-github.com/fiatjaf/go-nostr v0.1.0 h1:dTV7J6MPdFaFIMG+QWIbWWqtrem1nvVuXe84+6kCJ3E=
-github.com/fiatjaf/go-nostr v0.1.0/go.mod h1:Zwa4KwVMy3gLoMbbrH+NOZvqmrDADCIV+C67ew7VEqs=
+github.com/fiatjaf/go-nostr v0.1.1 h1:mMUn+Dr0QfhM1JuBHcGvvV0ON/tkinvOfXF8Yh825Xc=
+github.com/fiatjaf/go-nostr v0.1.1/go.mod h1:Zwa4KwVMy3gLoMbbrH+NOZvqmrDADCIV+C67ew7VEqs=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
 github.com/go-sql-driver/mysql v1.5.0 h1:ozyZYNQW3x3HtqT1jira07DN2PArx2v7/mN66gGcHOs=
 github.com/go-sql-driver/mysql v1.5.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=
diff --git a/handlers.go b/handlers.go
index e1b8728..d3a8647 100644
--- a/handlers.go
+++ b/handlers.go
@@ -146,12 +146,11 @@ func handleWebsocket(w http.ResponseWriter, r *http.Request) {
 		for {
 			select {
 			case <-ticker.C:
-				err := conn.WriteMessage(websocket.TextMessage, []byte("PING"))
+				err := conn.WriteMessage(websocket.PingMessage, nil)
 				if err != nil {
 					log.Warn().Err(err).Msg("error writing ping, closing websocket")
 					return
 				}
-				conn.WriteMessage(websocket.PingMessage, nil)
 			}
 		}
 	}()
diff --git a/listener.go b/listener.go
index fabd431..2469983 100644
--- a/listener.go
+++ b/listener.go
@@ -46,6 +46,11 @@ func notifyListeners(event *event.Event) {
 	for id, listener := range listeners {
 		match := false
 		for _, filter := range listener.filters {
+			if filter == nil {
+				match = false
+				break
+			}
+
 			if filter.Matches(event) {
 				match = true
 				break
diff --git a/query.go b/query.go
index eb3d7dd..eb3c03d 100644
--- a/query.go
+++ b/query.go
@@ -3,6 +3,7 @@ package main
 import (
 	"database/sql"
 	"encoding/hex"
+	"errors"
 	"fmt"
 	"strings"
 
@@ -14,6 +15,11 @@ func queryEvents(filter *filter.EventFilter) (events []event.Event, err error) {
 	var conditions []string
 	var params []interface{}
 
+	if filter == nil {
+		err = errors.New("filter cannot be null")
+		return
+	}
+
 	if filter.ID != "" {
 		conditions = append(conditions, "id = ?")
 		params = append(params, filter.ID)