diff --git a/internal/webserver/handler_login.go b/internal/webserver/handler_login.go
index 0f1f9cb..074d3e2 100644
--- a/internal/webserver/handler_login.go
+++ b/internal/webserver/handler_login.go
@@ -115,8 +115,6 @@ func (app *Application) ChangeSession(w http.ResponseWriter, r *http.Request) {
 		app.error_400_with_message(w, fmt.Sprintf("User not in database: %s", form.AccountName))
 		return
 	}
-	data := Notifications{
-		NumMessageNotifications: len(app.Profile.GetUnreadConversations(app.ActiveUser.ID)),
-	}
+	data := Notifications{NumMessageNotifications: len(app.Profile.GetUnreadConversations(app.ActiveUser.ID))}
 	app.buffered_render_htmx(w, "nav-sidebar", PageGlobalData{}, data)
 }
diff --git a/internal/webserver/handler_sidebar.go b/internal/webserver/handler_sidebar.go
new file mode 100644
index 0000000..913b16d
--- /dev/null
+++ b/internal/webserver/handler_sidebar.go
@@ -0,0 +1,18 @@
+package webserver
+
+import (
+	"net/http"
+)
+
+func (app *Application) NavSidebarPollUpdates(w http.ResponseWriter, r *http.Request) {
+	app.traceLog.Printf("'NavSidebarPollUpdates' handler (path: %q)", r.URL.Path)
+
+	// Must be an HTMX request, otherwise HTTP 400
+	if r.Header.Get("HX-Request") != "true" {
+		app.error_400_with_message(w, "This is an HTMX-only endpoint, not a page")
+		return
+	}
+
+	data := Notifications{NumMessageNotifications: len(app.Profile.GetUnreadConversations(app.ActiveUser.ID))}
+	app.buffered_render_htmx(w, "nav-sidebar", PageGlobalData{}, data)
+}
diff --git a/internal/webserver/server.go b/internal/webserver/server.go
index f8ec95a..a857039 100644
--- a/internal/webserver/server.go
+++ b/internal/webserver/server.go
@@ -124,6 +124,8 @@ func (app *Application) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		http.StripPrefix("/lists", http.HandlerFunc(app.Lists)).ServeHTTP(w, r)
 	case "messages":
 		http.StripPrefix("/messages", http.HandlerFunc(app.Messages)).ServeHTTP(w, r)
+	case "nav-sidebar-poll-updates":
+		app.NavSidebarPollUpdates(w, r)
 	default:
 		app.UserFeed(w, r)
 	}
diff --git a/internal/webserver/tpl/includes/nav_sidebar.tpl b/internal/webserver/tpl/includes/nav_sidebar.tpl
index 6ac258e..641297a 100644
--- a/internal/webserver/tpl/includes/nav_sidebar.tpl
+++ b/internal/webserver/tpl/includes/nav_sidebar.tpl
@@ -1,5 +1,5 @@
 {{define "nav-sidebar"}}
-  <nav id="nav-sidebar" class="nav-sidebar">
+  <nav id="nav-sidebar" class="nav-sidebar" hx-trigger="load delay:10s" hx-get="/nav-sidebar-poll-updates" hx-swap="outerHTML">
     <div id="logged-in-user-info">
       <div class="button row" hx-get="/login" hx-trigger="click" hx-target="body" hx-push-url="true">
         {{template "author-info" active_user}}