diff --git a/worker.js b/worker.js
index c47caad..3766d3c 100644
--- a/worker.js
+++ b/worker.js
@@ -26,39 +26,39 @@ async function process_request(details) {
     try {
         let hostname = (new URL(details.url)).hostname;
         let securityInfo = await browser.webRequest.getSecurityInfo(details.requestId, { certificateChain: true, rawDER: true });
-        if (securityInfo.state !== "insecure") {
-            const fingerprint = securityInfo.certificates[0].fingerprint.sha256;
-
-            let fpData = localStorage.getItem(fingerprint);
-
+        if (securityInfo.certificates.length > 0) {
             const currentTime = Date.now();
-            if (fpData) {
-                fpData = JSON.parse(fpData);
-                // If the last request was less than 10 minutes ago, don't spam the API
-                if (fpData.lastCheck && currentTime - fpData.lastCheck < 10 * 60 * 1000) {
-                    return;
-                }
-                // If the last response was less than 12 hours ago, don't check again
-                if (fpData.lastResponse && currentTime - fpData.lastResponse < 12 * 60 * 60 * 1000) {
-                    return;
-                }
-            } else {
-                fpData = {};
-            }
-
-            fpData.lastCheck = currentTime;
-            localStorage.setItem(fingerprint, JSON.stringify(fpData));
-
-            const tab = details.tabId;
-            if (!send_buffer[tab]) {
-                send_buffer[tab] = {};
-            }
-            if (!send_buffer[tab][hostname]) {
-                send_buffer[tab][hostname] = {};
-            }
-
             securityInfo.certificates.forEach(cert => {
-                send_buffer[tab][hostname][cert.fingerprint.sha256] = cert.rawDER;
+                const fingerprint = cert.fingerprint.sha256;
+
+                let fpData = localStorage.getItem(fingerprint);
+
+                if (fpData) {
+                    fpData = JSON.parse(fpData);
+                    // If the last request was less than 10 minutes ago, don't spam the API
+                    if (fpData.lastCheck && currentTime - fpData.lastCheck < 10 * 60 * 1000) {
+                        return;
+                    }
+                    // If the last response was less than 12 hours ago, don't check again
+                    if (fpData.lastResponse && currentTime - fpData.lastResponse < 12 * 60 * 60 * 1000) {
+                        return;
+                    }
+                } else {
+                    fpData = {};
+                }
+
+                fpData.lastCheck = currentTime;
+                localStorage.setItem(fingerprint, JSON.stringify(fpData));
+
+                const tab = details.tabId;
+                if (!send_buffer[tab]) {
+                    send_buffer[tab] = {};
+                }
+                if (!send_buffer[tab][hostname]) {
+                    send_buffer[tab][hostname] = {};
+                }
+
+                send_buffer[tab][hostname][fingerprint] = cert.rawDER;
             });
         }
     } catch (error) {
@@ -66,6 +66,20 @@ async function process_request(details) {
     }
 }
 
+function generate_alerts(fingerprints) {
+    fingerprints.forEach(fingerprint => {
+        let fpData = localStorage.getItem(fingerprint);
+        fpData = JSON.parse(fpData);
+        if (fpData.alert === true) {
+            browser.notifications.create({
+                "type": "basic",
+                "iconUrl": browser.runtime.getURL("icons/crowdtls-48.png"),
+                "title": "CrowdTLS Alert",
+                "message": fpData.alertMsg
+            });
+        }
+    });
+}
 
 /**
  * Checks the fingerprint and sends a REST GET request to the API.
@@ -95,12 +109,28 @@ async function do_checks(buffer) {
 
         const data = await response.json();
 
+        if (data["anomalies"]) {
+            const currentTime = Date.now();
+            Object.keys(data["anomalies"]).forEach(fingerprint => {
+                let fpData = localStorage.getItem(fingerprint);
+                fpData = JSON.parse(fpData);
+                fpData.lastCheck = currentTime;
+                fpData.lastResponse = currentTime;
+                fpData.alert = true;
+                fpData.alertTime = currentTime;
+                fpData.alertMsg = data["anomalies"][fingerprint];
+                localStorage.setItem(fingerprint, JSON.stringify(fpData));
+            });
+            generate_alerts(Object.keys(data["anomalies"]));
+        }
+
+
         Object.keys(buffer).forEach(hostname => {
             if (!data[hostname]) {
                 delete buffer[hostname];
             }
         });
-        send_certificate_chain(buffer);
+        await send_certificate_chain(buffer);
     }
     catch (error) {
         console.error(error);
@@ -182,7 +212,7 @@ browser.webRequest.onHeadersReceived.addListener(
 
 // When a tab update happens (i.e., page load complete), send the buffered data
 browser.tabs.onUpdated.addListener(async (tabId, changeInfo, tab) => {
-    if (changeInfo.status === "complete" && send_buffer[tabId]) {
+    if ((changeInfo.status || tab.status) == 'complete' && send_buffer[tabId]) {
         await do_checks(send_buffer[tabId]);
         delete send_buffer[tabId];
     }