diff --git a/backend/src/controllers/settings.ts b/backend/src/controllers/settings.ts
index 7446ad9..14ac7d7 100644
--- a/backend/src/controllers/settings.ts
+++ b/backend/src/controllers/settings.ts
@@ -13,41 +13,38 @@ export const getSettings = () => {
 export const updateSettings = (data: Record<string, string>) => {
   const db = getDatabase();
   const results: Setting[] = [];
+  // Normalize legacy/frontend alias keys to canonical settings table keys.
+  const canonicalKey = (key: string) =>
+    ({
+      taxId: "companyTaxId",
+      phone: "companyPhone",
+      email: "companyEmail",
+      countryCode: "companyCountryCode",
+    })[key] ?? key;
+  const clearableKeys = new Set([
+    "companyTaxId",
+    "companyPhone",
+    "companyEmail",
+    "companyCountryCode",
+    "companyCity",
+    "companyPostalCode",
+    "locale",
+  ]);
 
   for (const [key, raw] of Object.entries(data)) {
+    const targetKey = canonicalKey(key);
     // Treat explicit empty strings for certain keys as clearing the setting
-    const shouldClear = [
-      "companyTaxId",
-      "taxId", // alias that may slip through
-      "companyPhone",
-      "phone", // alias
-      "companyEmail",
-      "email", // alias
-      "companyCountryCode",
-      "countryCode", // alias
-      "companyCity",
-      "companyPostalCode",
-      "locale",
-    ].includes(key) && String(raw).trim() === "";
+    const shouldClear = clearableKeys.has(targetKey) && String(raw).trim() === "";
 
-    if (shouldClear) {
-      // delete the setting row if present
-      db.query("DELETE FROM settings WHERE key = ?", [
-        key === "taxId" ? "companyTaxId" : key,
-      ]);
-      results.push({ key: key === "taxId" ? "companyTaxId" : key, value: "" });
-      continue;
-    }
-
-    const value = String(raw);
+    const value = shouldClear ? "" : String(raw);
     // Upsert the setting
-    const existing = db.query("SELECT * FROM settings WHERE key = ?", [key]);
+    const existing = db.query("SELECT * FROM settings WHERE key = ?", [targetKey]);
     if (existing.length > 0) {
-      db.query("UPDATE settings SET value = ? WHERE key = ?", [value, key]);
+      db.query("UPDATE settings SET value = ? WHERE key = ?", [value, targetKey]);
     } else {
-      db.query("INSERT INTO settings (key, value) VALUES (?, ?)", [key, value]);
+      db.query("INSERT INTO settings (key, value) VALUES (?, ?)", [targetKey, value]);
     }
-    results.push({ key, value });
+    results.push({ key: targetKey, value });
   }
 
   return results;
diff --git a/frontend/src/lib/components/InvoiceEditor.svelte b/frontend/src/lib/components/InvoiceEditor.svelte
index 6f122c7..0ccf5d5 100644
--- a/frontend/src/lib/components/InvoiceEditor.svelte
+++ b/frontend/src/lib/components/InvoiceEditor.svelte
@@ -13,6 +13,23 @@
   let saving = $state(false);
   let error = $state("");
 
+  function createItemId() {
+    if (typeof globalThis.crypto?.randomUUID === "function") {
+      return globalThis.crypto.randomUUID();
+    }
+
+    if (typeof globalThis.crypto?.getRandomValues === "function") {
+      const bytes = new Uint8Array(16);
+      globalThis.crypto.getRandomValues(bytes);
+      bytes[6] = (bytes[6] & 0x0f) | 0x40;
+      bytes[8] = (bytes[8] & 0x3f) | 0x80;
+      const hex = Array.from(bytes, (b) => b.toString(16).padStart(2, "0"));
+      return `${hex.slice(0, 4).join("")}-${hex.slice(4, 6).join("")}-${hex.slice(6, 8).join("")}-${hex.slice(8, 10).join("")}-${hex.slice(10, 16).join("")}`;
+    }
+
+    return `${Date.now()}-${Math.random().toString(16).slice(2)}`;
+  }
+
   let form = $state({
     customerId: initInvoice?.customerId || "",
     invoiceNumber: initInvoice?.invoiceNumber ?? initNextInvoiceNumber,
@@ -32,13 +49,13 @@
     initInvoice?.items?.length
       ? initInvoice.items.map((i: any) => ({
           ...i,
-          id: crypto.randomUUID(),
+          id: createItemId(),
           unit: i.unit || "",
           productId: i.productId || "",
         }))
       : [
           {
-            id: crypto.randomUUID(),
+            id: createItemId(),
             productId: "",
             description: "",
             quantity: 1,
@@ -56,7 +73,7 @@
 
   function addItem() {
     items.push({
-      id: crypto.randomUUID(),
+      id: createItemId(),
       productId: "",
       description: "",
       quantity: 1,