diff --git a/website/app/Http/Controllers/Account/BillingController.php b/website/app/Http/Controllers/Account/BillingController.php
index 29ab799..032f1b4 100644
--- a/website/app/Http/Controllers/Account/BillingController.php
+++ b/website/app/Http/Controllers/Account/BillingController.php
@@ -91,7 +91,7 @@ class BillingController extends Controller
                 $paymentMethods[] = [
                     'id' => $method->id,
                     'brand' => $method->card->brand ?? 'unknown',
-                    'last_four' => $method->card->last_four ?? '****',
+                    'last_four' => $method->card->last4 ?? '****',
                     'exp_month' => $method->card->exp_month,
                     'exp_year' => $method->card->exp_year,
                     'is_default' => $method->id === $defaultPaymentMethod,
diff --git a/website/app/Http/Controllers/Admin/DashboardController.php b/website/app/Http/Controllers/Admin/DashboardController.php
index 8cc55e7..6392699 100644
--- a/website/app/Http/Controllers/Admin/DashboardController.php
+++ b/website/app/Http/Controllers/Admin/DashboardController.php
@@ -10,6 +10,7 @@ use App\Models\PaymentTransaction;
 use App\Models\Plan;
 use App\Models\Service;
 use App\Models\User;
+use Illuminate\Support\Facades\Cache;
 use Illuminate\Support\Facades\DB;
 use Inertia\Inertia;
 use Inertia\Response;
@@ -19,181 +20,185 @@ class DashboardController extends Controller
 {
     public function index(): Response
     {
-        $totalCustomers = User::role('customer')->count();
+        $stats = Cache::remember('admin.dashboard.stats', 300, function () {
+            $totalCustomers = User::role('customer')->count();
 
-        // MRR: sum of plan prices for active subscriptions
-        $mrr = Subscription::query()
-            ->where('stripe_status', 'active')
-            ->whereNotNull('plan_id')
-            ->join('plans', 'subscriptions.plan_id', '=', 'plans.id')
-            ->sum('plans.price');
+            // MRR: sum of plan prices for active subscriptions
+            $mrr = (float) Subscription::query()
+                ->where('stripe_status', 'active')
+                ->whereNotNull('plan_id')
+                ->join('plans', 'subscriptions.plan_id', '=', 'plans.id')
+                ->sum('plans.price');
 
-        // Total revenue: sum of paid invoice totals
-        $totalRevenue = Invoice::query()
-            ->where('status', 'paid')
-            ->sum('total');
+            // Total revenue: sum of paid invoice totals
+            $totalRevenue = (float) Invoice::query()
+                ->where('status', 'paid')
+                ->sum('total');
 
-        $activeServices = Service::query()
-            ->where('status', 'active')
-            ->count();
-
-        // Pending invoices
-        $pendingInvoicesCount = Invoice::query()
-            ->where('status', 'pending')
-            ->count();
-
-        $pendingInvoicesAmount = Invoice::query()
-            ->where('status', 'pending')
-            ->sum('total');
-
-        // Overdue invoices
-        $overdueCount = Invoice::query()
-            ->where('status', 'overdue')
-            ->count();
-
-        $overdueAmount = Invoice::query()
-            ->where('status', 'overdue')
-            ->sum('total');
-
-        // Recent invoices with user info
-        $recentInvoices = Invoice::query()
-            ->with('user:id,name,email')
-            ->latest()
-            ->limit(10)
-            ->get(['id', 'user_id', 'number', 'total', 'status', 'gateway', 'created_at']);
-
-        // Recent subscriptions with user and plan
-        $recentSubscriptions = Subscription::query()
-            ->select([
-                'subscriptions.id',
-                'subscriptions.user_id',
-                'subscriptions.plan_id',
-                'subscriptions.type',
-                'subscriptions.stripe_status',
-                'subscriptions.gateway',
-                'subscriptions.created_at',
-            ])
-            ->leftJoin('plans', 'subscriptions.plan_id', '=', 'plans.id')
-            ->addSelect([
-                'plans.name as plan_name',
-                'plans.price as plan_price',
-                'plans.billing_cycle as plan_billing_cycle',
-            ])
-            ->leftJoin('users', 'subscriptions.user_id', '=', 'users.id')
-            ->addSelect([
-                'users.name as user_name',
-                'users.email as user_email',
-            ])
-            ->orderByDesc('subscriptions.created_at')
-            ->limit(10)
-            ->get();
-
-        // Popular plans: ordered by active subscription count
-        $popularPlans = Plan::query()
-            ->withCount(['services as active_services_count' => function ($query): void {
-                $query->where('status', 'active');
-            }])
-            ->where('status', 'active')
-            ->orderByDesc('active_services_count')
-            ->limit(8)
-            ->get(['id', 'name', 'service_type', 'price', 'billing_cycle']);
-
-        // Revenue by service type from plans linked through invoices
-        $revenueByServiceType = Invoice::query()
-            ->where('invoices.status', 'paid')
-            ->join('subscriptions', 'invoices.subscription_id', '=', 'subscriptions.id')
-            ->join('plans', 'subscriptions.plan_id', '=', 'plans.id')
-            ->select('plans.service_type', DB::raw('SUM(invoices.total) as revenue'), DB::raw('COUNT(invoices.id) as invoice_count'))
-            ->groupBy('plans.service_type')
-            ->orderByDesc('revenue')
-            ->get();
-
-        // New customers this month
-        $newCustomersThisMonth = User::role('customer')
-            ->where('created_at', '>=', now()->startOfMonth())
-            ->count();
-
-        // Revenue this month
-        $revenueThisMonth = Invoice::query()
-            ->where('status', 'paid')
-            ->where('paid_at', '>=', now()->startOfMonth())
-            ->sum('total');
-
-        // ARR (Annual Recurring Revenue)
-        $arr = (float) $mrr * 12;
-
-        // Monthly Revenue Trend (last 12 months)
-        $revenueByMonth = PaymentTransaction::query()
-            ->where('status', 'completed')
-            ->where('created_at', '>=', now()->subMonths(12))
-            ->selectRaw("DATE_FORMAT(created_at, '%Y-%m') as month, SUM(amount) as total")
-            ->groupBy('month')
-            ->orderBy('month')
-            ->get()
-            ->map(fn ($row) => ['month' => $row->month, 'total' => (float) $row->total]);
-
-        // Customer Growth (last 12 months - new signups per month)
-        $customerGrowth = User::role('customer')
-            ->where('created_at', '>=', now()->subMonths(12))
-            ->selectRaw("DATE_FORMAT(created_at, '%Y-%m') as month, COUNT(*) as count")
-            ->groupBy('month')
-            ->orderBy('month')
-            ->get()
-            ->map(fn ($row) => ['month' => $row->month, 'count' => (int) $row->count]);
-
-        // Churn Rate (subscriptions cancelled vs total in last 6 months)
-        $churnData = [];
-        for ($i = 5; $i >= 0; $i--) {
-            $monthStart = now()->subMonths($i)->startOfMonth();
-            $monthEnd = now()->subMonths($i)->endOfMonth();
-
-            $totalAtStart = Subscription::query()
-                ->where('created_at', '<', $monthStart)
-                ->where(function ($query) use ($monthStart): void {
-                    $query->whereNull('cancelled_at')
-                        ->orWhere('cancelled_at', '>', $monthStart);
-                })
+            $activeServices = Service::query()
+                ->where('status', 'active')
                 ->count();
 
-            $cancelled = Subscription::query()
-                ->whereBetween('cancelled_at', [$monthStart, $monthEnd])
+            // Pending invoices
+            $pendingInvoicesCount = Invoice::query()
+                ->where('status', 'pending')
                 ->count();
 
-            $churnData[] = [
-                'month' => $monthStart->format('Y-m'),
-                'rate' => $totalAtStart > 0 ? round(($cancelled / $totalAtStart) * 100, 1) : 0,
-                'cancelled' => $cancelled,
-            ];
-        }
+            $pendingInvoicesAmount = (float) Invoice::query()
+                ->where('status', 'pending')
+                ->sum('total');
 
-        // Overdue Invoices (detailed list)
-        $overdueInvoices = Invoice::query()
-            ->where('status', 'overdue')
-            ->with('user:id,name,email')
-            ->latest('due_date')
-            ->take(10)
-            ->get(['id', 'user_id', 'number', 'total', 'due_date', 'status']);
+            // Overdue invoices
+            $overdueCount = Invoice::query()
+                ->where('status', 'overdue')
+                ->count();
 
-        return Inertia::render('Admin/Dashboard', [
-            'totalCustomers' => $totalCustomers,
-            'mrr' => (float) $mrr,
-            'totalRevenue' => (float) $totalRevenue,
-            'activeServices' => $activeServices,
-            'pendingInvoicesCount' => $pendingInvoicesCount,
-            'pendingInvoicesAmount' => (float) $pendingInvoicesAmount,
-            'overdueCount' => $overdueCount,
-            'overdueAmount' => (float) $overdueAmount,
-            'recentInvoices' => $recentInvoices,
-            'recentSubscriptions' => $recentSubscriptions,
-            'popularPlans' => $popularPlans,
-            'revenueByServiceType' => $revenueByServiceType,
-            'newCustomersThisMonth' => $newCustomersThisMonth,
-            'revenueThisMonth' => (float) $revenueThisMonth,
-            'arr' => $arr,
-            'revenueByMonth' => $revenueByMonth,
-            'customerGrowth' => $customerGrowth,
-            'churnData' => $churnData,
-            'overdueInvoices' => $overdueInvoices,
-        ]);
+            $overdueAmount = (float) Invoice::query()
+                ->where('status', 'overdue')
+                ->sum('total');
+
+            // Recent invoices with user info
+            $recentInvoices = Invoice::query()
+                ->with('user:id,name,email')
+                ->latest()
+                ->limit(10)
+                ->get(['id', 'user_id', 'number', 'total', 'status', 'gateway', 'created_at']);
+
+            // Recent subscriptions with user and plan
+            $recentSubscriptions = Subscription::query()
+                ->select([
+                    'subscriptions.id',
+                    'subscriptions.user_id',
+                    'subscriptions.plan_id',
+                    'subscriptions.type',
+                    'subscriptions.stripe_status',
+                    'subscriptions.gateway',
+                    'subscriptions.created_at',
+                ])
+                ->leftJoin('plans', 'subscriptions.plan_id', '=', 'plans.id')
+                ->addSelect([
+                    'plans.name as plan_name',
+                    'plans.price as plan_price',
+                    'plans.billing_cycle as plan_billing_cycle',
+                ])
+                ->leftJoin('users', 'subscriptions.user_id', '=', 'users.id')
+                ->addSelect([
+                    'users.name as user_name',
+                    'users.email as user_email',
+                ])
+                ->orderByDesc('subscriptions.created_at')
+                ->limit(10)
+                ->get();
+
+            // Popular plans: ordered by active subscription count
+            $popularPlans = Plan::query()
+                ->withCount(['services as active_services_count' => function ($query): void {
+                    $query->where('status', 'active');
+                }])
+                ->where('status', 'active')
+                ->orderByDesc('active_services_count')
+                ->limit(8)
+                ->get(['id', 'name', 'service_type', 'price', 'billing_cycle']);
+
+            // Revenue by service type from plans linked through invoices
+            $revenueByServiceType = Invoice::query()
+                ->where('invoices.status', 'paid')
+                ->join('subscriptions', 'invoices.subscription_id', '=', 'subscriptions.id')
+                ->join('plans', 'subscriptions.plan_id', '=', 'plans.id')
+                ->select('plans.service_type', DB::raw('SUM(invoices.total) as revenue'), DB::raw('COUNT(invoices.id) as invoice_count'))
+                ->groupBy('plans.service_type')
+                ->orderByDesc('revenue')
+                ->get();
+
+            // New customers this month
+            $newCustomersThisMonth = User::role('customer')
+                ->where('created_at', '>=', now()->startOfMonth())
+                ->count();
+
+            // Revenue this month
+            $revenueThisMonth = (float) Invoice::query()
+                ->where('status', 'paid')
+                ->where('paid_at', '>=', now()->startOfMonth())
+                ->sum('total');
+
+            // ARR (Annual Recurring Revenue)
+            $arr = $mrr * 12;
+
+            // Monthly Revenue Trend (last 12 months)
+            $revenueByMonth = PaymentTransaction::query()
+                ->where('status', 'completed')
+                ->where('created_at', '>=', now()->subMonths(12))
+                ->selectRaw("DATE_FORMAT(created_at, '%Y-%m') as month, SUM(amount) as total")
+                ->groupBy('month')
+                ->orderBy('month')
+                ->get()
+                ->map(fn ($row) => ['month' => $row->month, 'total' => (float) $row->total]);
+
+            // Customer Growth (last 12 months - new signups per month)
+            $customerGrowth = User::role('customer')
+                ->where('created_at', '>=', now()->subMonths(12))
+                ->selectRaw("DATE_FORMAT(created_at, '%Y-%m') as month, COUNT(*) as count")
+                ->groupBy('month')
+                ->orderBy('month')
+                ->get()
+                ->map(fn ($row) => ['month' => $row->month, 'count' => (int) $row->count]);
+
+            // Churn Rate (subscriptions cancelled vs total in last 6 months)
+            $churnData = [];
+            for ($i = 5; $i >= 0; $i--) {
+                $monthStart = now()->subMonths($i)->startOfMonth();
+                $monthEnd = now()->subMonths($i)->endOfMonth();
+
+                $totalAtStart = Subscription::query()
+                    ->where('created_at', '<', $monthStart)
+                    ->where(function ($query) use ($monthStart): void {
+                        $query->whereNull('cancelled_at')
+                            ->orWhere('cancelled_at', '>', $monthStart);
+                    })
+                    ->count();
+
+                $cancelled = Subscription::query()
+                    ->whereBetween('cancelled_at', [$monthStart, $monthEnd])
+                    ->count();
+
+                $churnData[] = [
+                    'month' => $monthStart->format('Y-m'),
+                    'rate' => $totalAtStart > 0 ? round(($cancelled / $totalAtStart) * 100, 1) : 0,
+                    'cancelled' => $cancelled,
+                ];
+            }
+
+            // Overdue Invoices (detailed list)
+            $overdueInvoices = Invoice::query()
+                ->where('status', 'overdue')
+                ->with('user:id,name,email')
+                ->latest('due_date')
+                ->take(10)
+                ->get(['id', 'user_id', 'number', 'total', 'due_date', 'status']);
+
+            return compact(
+                'totalCustomers',
+                'mrr',
+                'totalRevenue',
+                'activeServices',
+                'pendingInvoicesCount',
+                'pendingInvoicesAmount',
+                'overdueCount',
+                'overdueAmount',
+                'recentInvoices',
+                'recentSubscriptions',
+                'popularPlans',
+                'revenueByServiceType',
+                'newCustomersThisMonth',
+                'revenueThisMonth',
+                'arr',
+                'revenueByMonth',
+                'customerGrowth',
+                'churnData',
+                'overdueInvoices',
+            );
+        });
+
+        return Inertia::render('Admin/Dashboard', $stats);
     }
 }
diff --git a/website/app/Http/Controllers/Admin/InvoiceController.php b/website/app/Http/Controllers/Admin/InvoiceController.php
index 5c5e1ef..eca5952 100644
--- a/website/app/Http/Controllers/Admin/InvoiceController.php
+++ b/website/app/Http/Controllers/Admin/InvoiceController.php
@@ -15,6 +15,7 @@ use Barryvdh\DomPDF\Facade\Pdf;
 use Illuminate\Http\RedirectResponse;
 use Illuminate\Http\Request;
 use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Str;
 use Inertia\Inertia;
 use Inertia\Response;
 
@@ -75,7 +76,7 @@ class InvoiceController extends Controller
             });
 
             // Generate unique invoice number
-            $number = 'INV-'.str_pad((string) (Invoice::query()->count() + 1), 6, '0', STR_PAD_LEFT);
+            $number = 'INV-'.now()->format('Ymd').'-'.strtoupper(Str::random(6));
 
             $status = ($validated['send_immediately'] ?? false) ? 'pending' : 'draft';
 
diff --git a/website/app/Http/Controllers/Webhooks/PayPalWebhookController.php b/website/app/Http/Controllers/Webhooks/PayPalWebhookController.php
index 5ad32a5..159ef69 100644
--- a/website/app/Http/Controllers/Webhooks/PayPalWebhookController.php
+++ b/website/app/Http/Controllers/Webhooks/PayPalWebhookController.php
@@ -14,6 +14,7 @@ use App\Models\User;
 use Illuminate\Http\JsonResponse;
 use Illuminate\Http\Request;
 use Illuminate\Support\Facades\Log;
+use Illuminate\Support\Str;
 use Laravel\Cashier\Subscription;
 
 class PayPalWebhookController extends Controller
@@ -188,7 +189,7 @@ class PayPalWebhookController extends Controller
             'subscription_id' => $subscription->id,
             'gateway' => 'paypal',
             'gateway_invoice_id' => $resource['id'] ?? null,
-            'number' => config('billing.invoice.prefix').'-'.now()->format('Ymd').'-'.rand(1000, 9999),
+            'number' => config('billing.invoice.prefix', 'INV').'-'.now()->format('Ymd').'-'.strtoupper(Str::random(6)),
             'total' => (float) ($resource['amount']['total'] ?? 0),
             'tax' => 0,
             'currency' => strtoupper($resource['amount']['currency'] ?? 'USD'),
diff --git a/website/app/Http/Controllers/Webhooks/StripeWebhookController.php b/website/app/Http/Controllers/Webhooks/StripeWebhookController.php
index 995c5c3..654b7c0 100644
--- a/website/app/Http/Controllers/Webhooks/StripeWebhookController.php
+++ b/website/app/Http/Controllers/Webhooks/StripeWebhookController.php
@@ -11,6 +11,7 @@ use App\Models\Invoice;
 use App\Models\PaymentTransaction;
 use App\Models\User;
 use Illuminate\Support\Facades\Log;
+use Illuminate\Support\Str;
 use Laravel\Cashier\Http\Controllers\WebhookController;
 use Symfony\Component\HttpFoundation\Response;
 
@@ -123,7 +124,7 @@ class StripeWebhookController extends WebhookController
                 'user_id' => $user->id,
                 'subscription_id' => $subscription?->id,
                 'gateway' => 'stripe',
-                'number' => $stripeInvoice['number'] ?? config('billing.invoice.prefix').'-'.now()->format('Ymd').'-'.rand(1000, 9999),
+                'number' => $stripeInvoice['number'] ?? config('billing.invoice.prefix', 'INV').'-'.now()->format('Ymd').'-'.strtoupper(Str::random(6)),
                 'total' => ($stripeInvoice['amount_paid'] ?? 0) / 100,
                 'tax' => ($stripeInvoice['tax'] ?? 0) / 100,
                 'currency' => strtoupper($stripeInvoice['currency'] ?? 'usd'),
diff --git a/website/database/migrations/2026_03_14_224955_add_performance_indexes.php b/website/database/migrations/2026_03_14_224955_add_performance_indexes.php
new file mode 100644
index 0000000..f5c17d1
--- /dev/null
+++ b/website/database/migrations/2026_03_14_224955_add_performance_indexes.php
@@ -0,0 +1,46 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::table('invoices', function (Blueprint $table) {
+            $table->index('status');
+        });
+
+        Schema::table('orders', function (Blueprint $table) {
+            $table->index('status');
+        });
+
+        Schema::table('audit_logs', function (Blueprint $table) {
+            $table->index('action');
+            $table->index('created_at');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::table('invoices', function (Blueprint $table) {
+            $table->dropIndex(['status']);
+        });
+
+        Schema::table('orders', function (Blueprint $table) {
+            $table->dropIndex(['status']);
+        });
+
+        Schema::table('audit_logs', function (Blueprint $table) {
+            $table->dropIndex(['action']);
+            $table->dropIndex(['created_at']);
+        });
+    }
+};
diff --git a/website/routes/account.php b/website/routes/account.php
index cf17157..9bc186d 100644
--- a/website/routes/account.php
+++ b/website/routes/account.php
@@ -15,6 +15,9 @@ use App\Http\Controllers\Account\UpgradeController;
 use App\Http\Controllers\Account\VpsController;
 use Illuminate\Support\Facades\Route;
 
+// Impersonation stop (must be on account subdomain since impersonated user lacks admin role)
+Route::post('/impersonate/stop', [\App\Http\Controllers\Admin\ImpersonationController::class, 'stop'])->name('impersonation.stop');
+
 Route::get('/dashboard', [DashboardController::class, 'index'])->name('account.dashboard');
 
 Route::get('/profile', [ProfileController::class, 'show'])->name('account.profile');