diff --git a/background.js b/background.js
new file mode 100644
index 0000000..d6adb05
--- /dev/null
+++ b/background.js
@@ -0,0 +1,49 @@
+// Extension initialization
+chrome.runtime.onInstalled.addListener(() => {
+    console.log("Word Replacer Addon installed.");
+    
+    // Set default replacements if they don't already exist
+    chrome.storage.local.get('wordReplacements', (data) => {
+        if (!data.wordReplacements) {
+            chrome.storage.local.set({
+                wordReplacements: {
+                    "oldWord1": "newWord1",
+                    "oldWord2": "newWord2",
+                    "oldWord3": "newWord3"
+                }
+            });
+        }
+    });
+});
+
+// Data cleanup when possible
+function cleanupStorageData() {
+    chrome.storage.local.clear(() => {
+        console.log("Extension storage cleared.");
+    });
+}
+
+// For Firefox we can use onSuspend which is called when the extension process
+// is terminated (can happen on deactivation or uninstallation)
+chrome.runtime.onSuspend.addListener(() => {
+    console.log("Word Replacer Addon terminated.");
+    // Uncomment the following line if you want to remove all data on suspension
+    // cleanupStorageData();
+});
+
+// Add a command to manually clean the data
+chrome.runtime.onMessage.addListener((message, sender, sendResponse) => {
+    if (message.action === 'getReplacements') {
+        chrome.storage.local.get('wordReplacements', (data) => {
+            sendResponse(data.wordReplacements || {});
+        });
+        return true; // Required for asynchronous sendResponse
+    }
+    
+    // New command to clean the data
+    if (message.action === 'clearStorageData') {
+        cleanupStorageData();
+        sendResponse({success: true});
+        return true;
+    }
+});
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diff --git a/manifest.json b/manifest.json
new file mode 100644
index 0000000..68e541e
--- /dev/null
+++ b/manifest.json
@@ -0,0 +1,52 @@
+{
+  "manifest_version": 2,
+  "name": "Word Replacer",
+  "version": "1.0.0",
+  "description": "Replaces specific words in web pages with customizable alternatives.",
+  "author": "krypt77",
+  "homepage_url": "https://gitea.it/krypt77/Firefox-Word-Replacer-Addon",
+  
+  "permissions": [
+    "activeTab",
+    "storage",
+    "tabs"
+  ],
+  
+  "background": {
+    "scripts": ["background.js"],
+    "persistent": false
+  },
+  
+  "content_scripts": [
+    {
+      "matches": ["<all_urls>"],
+      "js": ["content_scripts/replacer.js"],
+      "run_at": "document_end"
+    }
+  ],
+  
+  "icons": {
+    "48": "icons/icon-48.png",
+    "96": "icons/icon-96.png"
+  },
+  
+  "browser_action": {
+    "default_icon": {
+      "48": "icons/icon-48.png"
+    },
+    "default_title": "Word Replacer",
+    "default_popup": "popup/options.html"
+  },
+  
+  "options_ui": {
+    "page": "popup/options.html",
+    "open_in_tab": true
+  },
+  
+  "applications": {
+    "gecko": {
+      "id": "word-replacer@krypt77.com",
+      "strict_min_version": "57.0"
+    }
+  }
+}
\ No newline at end of file