diff --git a/config/notification_unix.go b/config/notification_unix.go
new file mode 100644
index 0000000..58a121c
--- /dev/null
+++ b/config/notification_unix.go
@@ -0,0 +1,7 @@
+//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris
+
+package config
+
+func defaultNotifyCommand() string {
+	return "/usr/share/barnard/barnard-sound.sh \"%event\" \"%who\" \"%what\""
+}
diff --git a/config/notification_windows.go b/config/notification_windows.go
new file mode 100644
index 0000000..fe62cb3
--- /dev/null
+++ b/config/notification_windows.go
@@ -0,0 +1,9 @@
+//go:build windows
+
+package config
+
+// Windows installations do not ship the POSIX notification helper. Users can
+// configure a cmd.exe-compatible command explicitly if they want notifications.
+func defaultNotifyCommand() string {
+	return ""
+}
diff --git a/config/user_config.go b/config/user_config.go
index 529dea2..5cdfb22 100644
--- a/config/user_config.go
+++ b/config/user_config.go
@@ -150,7 +150,7 @@ func (c *Config) LoadConfig() {
 		jc.Username = &username
 	}
 	if c.config.NotifyCommand == nil {
-		ncmd := string("/usr/share/barnard/barnard-sound.sh \"%event\" \"%who\" \"%what\"")
+		ncmd := defaultNotifyCommand()
 		jc.NotifyCommand = &ncmd
 	}
 	if c.config.NoiseSuppressionEnabled == nil {
diff --git a/main.go b/main.go
index 4398e51..8ddde60 100644
--- a/main.go
+++ b/main.go
@@ -9,7 +9,6 @@ import (
 	"log"
 	"net/http"
 	"os"
-	"os/exec"
 	"strings"
 	"time"
 
@@ -45,31 +44,28 @@ func do_list_devices() {
 	show_devs("Inputs:", idevs)
 }
 
-func setup_notify_runner(notify_command string) chan []string {
-	t := make(chan []string)
-	var do_nothing = false
-	var err error
-	if err != nil {
-	}
-	if notify_command == "" {
-		do_nothing = true
-	}
-	go func(events chan []string, cmd_template string, dummy bool) {
-		for {
-			event := <-events
-			if !dummy {
-				t := string(cmd_template)
-				t = strings.ReplaceAll(t, "%event", shellescape.Quote(event[0]))
-				t = strings.ReplaceAll(t, "%who", shellescape.Quote(event[1]))
-				t = strings.ReplaceAll(t, "%what", shellescape.Quote(event[2]))
-				cmd := "/bin/sh"
-				args := []string{"-c", t}
-				x := exec.Command(cmd, args...)
-				x.Run()
-			} //if we actually have a command to run
-		} //for
-	}(t, notify_command, do_nothing)
-	return t
+const notificationQueueSize = 32
+
+func setup_notify_runner(notifyCommand string) chan []string {
+	events := make(chan []string, notificationQueueSize)
+	go func() {
+		for event := range events {
+			if notifyCommand != "" {
+				runNotification(expandNotification(notifyCommand, event))
+			}
+		}
+	}()
+	return events
+}
+
+// expandNotification replaces placeholders in one pass so text supplied for
+// one field cannot cause another placeholder to be expanded recursively.
+func expandNotification(template string, event []string) string {
+	return strings.NewReplacer(
+		"%event", shellescape.Quote(event[0]),
+		"%who", shellescape.Quote(event[1]),
+		"%what", shellescape.Quote(event[2]),
+	).Replace(template)
 }
 
 func main() {
diff --git a/notification_unix.go b/notification_unix.go
new file mode 100644
index 0000000..946395c
--- /dev/null
+++ b/notification_unix.go
@@ -0,0 +1,9 @@
+//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris
+
+package main
+
+import "os/exec"
+
+func runNotification(command string) {
+	_ = exec.Command("/bin/sh", "-c", command).Run()
+}
diff --git a/notification_windows.go b/notification_windows.go
new file mode 100644
index 0000000..5c969e1
--- /dev/null
+++ b/notification_windows.go
@@ -0,0 +1,9 @@
+//go:build windows
+
+package main
+
+import "os/exec"
+
+func runNotification(command string) {
+	_ = exec.Command("cmd.exe", "/C", command).Run()
+}
diff --git a/ui.go b/ui.go
index 5afe6ca..0f67af3 100644
--- a/ui.go
+++ b/ui.go
@@ -39,7 +39,12 @@ func esc(str string) string {
 }
 
 func (b *Barnard) Notify(event string, who string, what string) {
-	b.notifyChannel <- []string{event, who, what}
+	// Notifications are best-effort: a slow external command must not block a
+	// UI or network callback. New events are dropped once the bounded queue is full.
+	select {
+	case b.notifyChannel <- []string{event, who, what}:
+	default:
+	}
 }
 
 func (b *Barnard) Beep() {