diff --git a/app/Http/Controllers/Site/PriceStreamController.php b/app/Http/Controllers/Site/PriceStreamController.php
index b991ff6..f1a6912 100644
--- a/app/Http/Controllers/Site/PriceStreamController.php
+++ b/app/Http/Controllers/Site/PriceStreamController.php
@@ -45,7 +45,7 @@ class PriceStreamController extends Controller
                 $send('last', $last);
             }
 
-            $list = app(PriceBroadcastService::class)->buildListPayload();
+            $list = app(PriceBroadcastService::class)->buildListPayload(true);
             if (is_array($list) && $list !== []) {
                 $send('list', $list);
             }
diff --git a/app/Services/PriceBroadcastService.php b/app/Services/PriceBroadcastService.php
index 0f8fc3c..9c5de66 100644
--- a/app/Services/PriceBroadcastService.php
+++ b/app/Services/PriceBroadcastService.php
@@ -12,6 +12,10 @@ class PriceBroadcastService
 
     private const LIST_HASH_KEY = 'price_broadcast:list_hash';
 
+    private const LIST_SNAPSHOT_KEY = 'price_broadcast:list_snapshot';
+
+    private const LIST_SNAPSHOT_SECONDS = 8;
+
     /**
      * برادکست SSE — payload کامل last/list وقتی داده عوض شود.
      *
@@ -90,9 +94,29 @@ class PriceBroadcastService
         $this->publishListIfChanged(true);
     }
 
-    public function buildListPayload(): ?array
+    public function buildListPayload(bool $allowCached = false): ?array
     {
-        return $this->buildProductListPayload();
+        if ($allowCached) {
+            $cached = Cache::get(self::LIST_SNAPSHOT_KEY);
+            if (
+                is_array($cached)
+                && is_array($cached['body'] ?? null)
+                && isset($cached['stored_at'])
+                && now()->diffInSeconds($cached['stored_at']) <= self::LIST_SNAPSHOT_SECONDS
+            ) {
+                return $cached['body'];
+            }
+        }
+
+        $body = $this->buildProductListPayload();
+        if ($body !== null && $body !== []) {
+            Cache::put(self::LIST_SNAPSHOT_KEY, [
+                'body' => $body,
+                'stored_at' => now(),
+            ], now()->addSeconds(self::LIST_SNAPSHOT_SECONDS + 5));
+        }
+
+        return $body;
     }
 
     public function broadcastListIfChanged(bool $force = false): bool
@@ -112,14 +136,15 @@ class PriceBroadcastService
             return false;
         }
 
-        if (! $force && ! $this->rememberHashIfChanged(self::LIST_HASH_KEY, $this->listIdentity($listPayload))) {
+        if (! $force && ! $this->rememberHashIfChanged(self::LIST_HASH_KEY, self::listIdentity($listPayload))) {
             return false;
         }
 
         if ($force) {
-            $this->rememberHashIfChanged(self::LIST_HASH_KEY, $this->listIdentity($listPayload));
+            $this->rememberHashIfChanged(self::LIST_HASH_KEY, self::listIdentity($listPayload));
         }
 
+        Cache::forget(self::LIST_SNAPSHOT_KEY);
         app(PriceStreamService::class)->publish('list', $listPayload);
 
         return true;
@@ -129,7 +154,7 @@ class PriceBroadcastService
      * @param array<int, array<string, mixed>> $listPayload
      * @return array<int, array<string, int|bool>>
      */
-    private function listIdentity(array $listPayload): array
+    public static function listIdentity(array $listPayload): array
     {
         $identity = [];
 
diff --git a/app/Services/PriceStreamService.php b/app/Services/PriceStreamService.php
index 2d811b5..12a7b8c 100644
--- a/app/Services/PriceStreamService.php
+++ b/app/Services/PriceStreamService.php
@@ -99,28 +99,31 @@ class PriceStreamService
         }
 
         $key = $this->inboxKey();
-        $inbox = Cache::get($key, ['seq' => 0, 'events' => []]);
-        $events = is_array($inbox['events'] ?? null) ? $inbox['events'] : [];
-        $lastEvent = $events !== [] ? $events[array_key_last($events)] : null;
 
-        if (is_array($lastEvent)
-            && ($lastEvent['event'] ?? null) === $event
-            && $this->eventDataHash($event, $lastEvent['data'] ?? null) === $this->eventDataHash($event, $data)) {
-            return;
-        }
+        Cache::lock($key.':lock', 5)->block(3, function () use ($key, $event, $data): void {
+            $inbox = Cache::get($key, ['seq' => 0, 'events' => []]);
+            $events = is_array($inbox['events'] ?? null) ? $inbox['events'] : [];
+            $lastEvent = $events !== [] ? $events[array_key_last($events)] : null;
 
-        $inbox['seq'] = (int) ($inbox['seq'] ?? 0) + 1;
-        $inbox['events'][] = [
-            'id' => $inbox['seq'],
-            'event' => $event,
-            'data' => $data,
-        ];
+            if (is_array($lastEvent)
+                && ($lastEvent['event'] ?? null) === $event
+                && $this->eventDataHash($event, $lastEvent['data'] ?? null) === $this->eventDataHash($event, $data)) {
+                return;
+            }
 
-        if (count($inbox['events']) > self::MAX_EVENTS) {
-            $inbox['events'] = array_slice($inbox['events'], -self::MAX_EVENTS);
-        }
+            $inbox['seq'] = (int) ($inbox['seq'] ?? 0) + 1;
+            $inbox['events'][] = [
+                'id' => $inbox['seq'],
+                'event' => $event,
+                'data' => $data,
+            ];
 
-        Cache::put($key, $inbox, now()->addSeconds(self::INBOX_TTL_SECONDS));
+            if (count($inbox['events']) > self::MAX_EVENTS) {
+                $inbox['events'] = array_slice($inbox['events'], -self::MAX_EVENTS);
+            }
+
+            Cache::put($key, $inbox, now()->addSeconds(self::INBOX_TTL_SECONDS));
+        });
     }
 
     private function inboxKey(): string
@@ -142,22 +145,7 @@ class PriceStreamService
         }
 
         if ($event === 'list') {
-            $identity = [];
-            foreach ($data as $product) {
-                if (! is_array($product)) {
-                    continue;
-                }
-
-                $identity[] = [
-                    'id' => (int) ($product['id'] ?? 0),
-                    'price' => (int) ($product['price'] ?? 0),
-                    'price_profit' => (int) ($product['price_profit'] ?? 0),
-                    'show' => (bool) ($product['show'] ?? true),
-                    'active' => (bool) ($product['active'] ?? true),
-                ];
-            }
-
-            return md5(json_encode($identity, JSON_UNESCAPED_UNICODE));
+            return md5(json_encode(PriceBroadcastService::listIdentity($data), JSON_UNESCAPED_UNICODE));
         }
 
         return md5(json_encode($data, JSON_UNESCAPED_UNICODE));