diff --git a/server/routes/webhook.js b/server/routes/webhook.js
index bd8bd64..0a8ab47 100644
--- a/server/routes/webhook.js
+++ b/server/routes/webhook.js
@@ -167,6 +167,13 @@ router.post('/sonarr', (req, res) => {
     logToFile(`[Webhook] Sonarr event received - Type: ${eventType || 'unknown'}, Instance: ${instanceName || 'unknown'}`);
     logToFile(`[Webhook] Sonarr payload: ${JSON.stringify(req.body)}`);
 
+    // Phase 5.1: update webhook metrics for polling optimization
+    const sonarrInstances = getSonarrInstances();
+    const instance = sonarrInstances.find(i => i.name === instanceName);
+    if (instance) {
+      cache.updateWebhookMetrics(instance.url);
+    }
+
     // Phase 2: background cache refresh + SSE broadcast (fire-and-forget)
     processWebhookEvent('sonarr', eventType).catch(err => {
       logToFile(`[Webhook] Sonarr background refresh error: ${err.message}`);
@@ -196,6 +203,13 @@ router.post('/radarr', (req, res) => {
     logToFile(`[Webhook] Radarr event received - Type: ${eventType || 'unknown'}, Instance: ${instanceName || 'unknown'}`);
     logToFile(`[Webhook] Radarr payload: ${JSON.stringify(req.body)}`);
 
+    // Phase 5.1: update webhook metrics for polling optimization
+    const radarrInstances = getRadarrInstances();
+    const instance = radarrInstances.find(i => i.name === instanceName);
+    if (instance) {
+      cache.updateWebhookMetrics(instance.url);
+    }
+
     // Phase 2: background cache refresh + SSE broadcast (fire-and-forget)
     processWebhookEvent('radarr', eventType).catch(err => {
       logToFile(`[Webhook] Radarr background refresh error: ${err.message}`);