diff --git a/.vscode/ftp-kr.sync.cache.json b/.vscode/ftp-kr.sync.cache.json
index fa4ec06..b53600c 100644
--- a/.vscode/ftp-kr.sync.cache.json
+++ b/.vscode/ftp-kr.sync.cache.json
@@ -125,8 +125,8 @@
           },
           "class.Products.php": {
             "type": "-",
-            "size": 49998,
-            "lmtime": 1772612176689,
+            "size": 50211,
+            "lmtime": 1772916736693,
             "modified": false
           },
           "class.Site.php": {
@@ -193,8 +193,8 @@
           },
           "class.Products.php": {
             "type": "-",
-            "size": 41405,
-            "lmtime": 1772612327756,
+            "size": 42460,
+            "lmtime": 1772916728114,
             "modified": false
           },
           "class.Users.php": {
@@ -786,8 +786,8 @@
         "products": {
           "main_view.php": {
             "type": "-",
-            "size": 77412,
-            "lmtime": 1772612193848,
+            "size": 77741,
+            "lmtime": 1772916753426,
             "modified": false
           },
           "product_history.php": {
diff --git a/api.php b/api.php
index b2099f2..74db4bf 100644
--- a/api.php
+++ b/api.php
@@ -37,6 +37,52 @@ $mdb = new medoo( [
   return R::getRedBean() -> dispense( $type );
 } );
 
+function api_json_response( $data, $http_code = 200 )
+{
+  http_response_code( (int) $http_code );
+  echo json_encode( $data );
+  exit;
+}
+
+function api_validate_api_key( $mdb )
+{
+  $api_key = trim( (string) \S::get( 'api_key' ) );
+  $stored_key = trim( (string) $mdb -> get( 'settings', 'setting_value', [ 'setting_key' => 'api_key' ] ) );
+
+  if ( $api_key === '' || $stored_key === '' || !hash_equals( $stored_key, $api_key ) )
+  {
+    api_json_response( [ 'result' => 'error', 'message' => 'Invalid api_key' ], 401 );
+  }
+}
+
+function api_get_product_by_offer_and_client( $mdb, $offer_id, $client_id )
+{
+  return $mdb -> query(
+    'SELECT p.id, p.name, p.title, p.google_product_category
+     FROM products p
+     JOIN clients cl ON p.client_id = cl.id
+     WHERE p.offer_id = :offer_id
+       AND cl.id = :client_id
+     LIMIT 1',
+    [
+      ':offer_id' => (string) $offer_id,
+      ':client_id' => (int) $client_id
+    ]
+  ) -> fetch( \PDO::FETCH_ASSOC );
+}
+
+function api_normalize_product_text( $value )
+{
+  $value = trim( (string) $value );
+
+  if ( $value === '' )
+  {
+    return null;
+  }
+
+  return $value;
+}
+
 // dodawanie domeny przez API
 if ( \S::get( 'action' ) == 'domain_tester_add' )
 {
@@ -124,14 +170,7 @@ if ( \S::get( 'action' ) == 'campaign_comment_add' )
 // Zmiana custom_label_4 dla produktu przez API
 if ( \S::get( 'action' ) == 'product_custom_label_4_set' )
 {
-  $api_key = trim( \S::get( 'api_key' ) );
-  $stored_key = $mdb -> get( 'settings', 'setting_value', [ 'setting_key' => 'api_key' ] );
-
-  if ( !$api_key || !$stored_key || $api_key !== $stored_key )
-  {
-    echo json_encode( [ 'result' => 'error', 'message' => 'Invalid api_key' ] );
-    exit;
-  }
+  api_validate_api_key( $mdb );
 
   $offer_id        = trim( \S::get( 'offer_id' ) );
   $client_id_param = trim( \S::get( 'client_id' ) );
@@ -139,34 +178,166 @@ if ( \S::get( 'action' ) == 'product_custom_label_4_set' )
 
   if ( !$offer_id || !$client_id_param )
   {
-    echo json_encode( [ 'result' => 'error', 'message' => 'Missing required params: offer_id, client_id' ] );
-    exit;
+    api_json_response( [ 'result' => 'error', 'message' => 'Missing required params: offer_id, client_id' ], 422 );
   }
 
-  $product = $mdb -> query(
-    'SELECT p.id
-     FROM products p
-     JOIN clients cl ON p.client_id = cl.id
-     WHERE p.offer_id = :offer_id
-       AND cl.id = :client_id
-     LIMIT 1',
-    [
-      ':offer_id'  => $offer_id,
-      ':client_id' => (int) $client_id_param
-    ]
-  ) -> fetch( \PDO::FETCH_ASSOC );
+  $product = api_get_product_by_offer_and_client( $mdb, $offer_id, (int) $client_id_param );
 
   if ( !$product )
   {
-    echo json_encode( [ 'result' => 'error', 'message' => 'Product not found' ] );
-    exit;
+    api_json_response( [ 'result' => 'error', 'message' => 'Product not found' ], 404 );
   }
 
   \factory\Products::set_product_data( $product['id'], 'custom_label_4', $custom_label_4 );
   \factory\Products::add_product_comment( $product['id'], 'Zmiana etykiety 4 na: ' . $custom_label_4 . ' (API)' );
 
-  echo json_encode( [ 'result' => 'ok' ] );
-  exit;
+  api_json_response( [ 'result' => 'ok' ] );
+}
+
+// Zmiana tytulu produktu przez API
+if ( \S::get( 'action' ) == 'product_title_set' )
+{
+  api_validate_api_key( $mdb );
+
+  $offer_id = trim( (string) \S::get( 'offer_id' ) );
+  $client_id_param = (int) \S::get( 'client_id' );
+  $new_title = api_normalize_product_text( \S::get( 'title' ) );
+
+  if ( $offer_id === '' || $client_id_param <= 0 )
+  {
+    api_json_response( [ 'result' => 'error', 'message' => 'Missing required params: offer_id, client_id' ], 422 );
+  }
+
+  $product = api_get_product_by_offer_and_client( $mdb, $offer_id, $client_id_param );
+
+  if ( !$product )
+  {
+    api_json_response( [ 'result' => 'error', 'message' => 'Product not found' ], 404 );
+  }
+
+  $old_title = (string) ( $product['title'] ?? '' );
+  \factory\Products::set_product_data( (int) $product['id'], 'title', $new_title );
+
+  $old_title_for_log = trim( $old_title ) !== '' ? $old_title : '[pusty]';
+  $new_title_for_log = $new_title !== null ? $new_title : '[pusty]';
+  \factory\Products::add_product_comment(
+    (int) $product['id'],
+    'Zmiana tytulu przez API: ' . $old_title_for_log . ' -> ' . $new_title_for_log
+  );
+
+  api_json_response( [
+    'result' => 'ok',
+    'product_id' => (int) $product['id'],
+    'offer_id' => $offer_id,
+    'client_id' => $client_id_param,
+    'title' => $new_title
+  ] );
+}
+
+// Sprawdzenie, czy tytul produktu byl juz zmieniony
+if ( \S::get( 'action' ) == 'product_title_changed_check' )
+{
+  api_validate_api_key( $mdb );
+
+  $offer_id = trim( (string) \S::get( 'offer_id' ) );
+  $client_id_param = (int) \S::get( 'client_id' );
+
+  if ( $offer_id === '' || $client_id_param <= 0 )
+  {
+    api_json_response( [ 'result' => 'error', 'message' => 'Missing required params: offer_id, client_id' ], 422 );
+  }
+
+  $product = api_get_product_by_offer_and_client( $mdb, $offer_id, $client_id_param );
+
+  if ( !$product )
+  {
+    api_json_response( [ 'result' => 'error', 'message' => 'Product not found' ], 404 );
+  }
+
+  $base_name = trim( (string) ( $product['name'] ?? '' ) );
+  $custom_title = trim( (string) ( $product['title'] ?? '' ) );
+  $is_changed = $custom_title !== '' && $custom_title !== $base_name;
+
+  api_json_response( [
+    'result' => 'ok',
+    'product_id' => (int) $product['id'],
+    'offer_id' => $offer_id,
+    'client_id' => $client_id_param,
+    'title_changed' => $is_changed,
+    'default_name' => $base_name,
+    'custom_title' => $custom_title !== '' ? $custom_title : null
+  ] );
+}
+
+// Zmiana Google Product Category przez API
+if ( \S::get( 'action' ) == 'product_google_category_set' )
+{
+  api_validate_api_key( $mdb );
+
+  $offer_id = trim( (string) \S::get( 'offer_id' ) );
+  $client_id_param = (int) \S::get( 'client_id' );
+  $google_category = api_normalize_product_text( \S::get( 'google_product_category' ) );
+
+  if ( $offer_id === '' || $client_id_param <= 0 )
+  {
+    api_json_response( [ 'result' => 'error', 'message' => 'Missing required params: offer_id, client_id' ], 422 );
+  }
+
+  $product = api_get_product_by_offer_and_client( $mdb, $offer_id, $client_id_param );
+
+  if ( !$product )
+  {
+    api_json_response( [ 'result' => 'error', 'message' => 'Product not found' ], 404 );
+  }
+
+  $old_category = (string) ( $product['google_product_category'] ?? '' );
+  \factory\Products::set_product_data( (int) $product['id'], 'google_product_category', $google_category );
+
+  $old_category_for_log = trim( $old_category ) !== '' ? $old_category : '[pusty]';
+  $new_category_for_log = $google_category !== null ? $google_category : '[pusty]';
+  \factory\Products::add_product_comment(
+    (int) $product['id'],
+    'Zmiana Google Product Category przez API: ' . $old_category_for_log . ' -> ' . $new_category_for_log
+  );
+
+  api_json_response( [
+    'result' => 'ok',
+    'product_id' => (int) $product['id'],
+    'offer_id' => $offer_id,
+    'client_id' => $client_id_param,
+    'google_product_category' => $google_category
+  ] );
+}
+
+// Odczyt Google Product Category przez API
+if ( \S::get( 'action' ) == 'product_google_category_get' )
+{
+  api_validate_api_key( $mdb );
+
+  $offer_id = trim( (string) \S::get( 'offer_id' ) );
+  $client_id_param = (int) \S::get( 'client_id' );
+
+  if ( $offer_id === '' || $client_id_param <= 0 )
+  {
+    api_json_response( [ 'result' => 'error', 'message' => 'Missing required params: offer_id, client_id' ], 422 );
+  }
+
+  $product = api_get_product_by_offer_and_client( $mdb, $offer_id, $client_id_param );
+
+  if ( !$product )
+  {
+    api_json_response( [ 'result' => 'error', 'message' => 'Product not found' ], 404 );
+  }
+
+  $google_category = trim( (string) ( $product['google_product_category'] ?? '' ) );
+
+  api_json_response( [
+    'result' => 'ok',
+    'product_id' => (int) $product['id'],
+    'offer_id' => $offer_id,
+    'client_id' => $client_id_param,
+    'google_product_category' => $google_category !== '' ? $google_category : null
+  ] );
 }
 
 // Open Page Rank - zapis
@@ -181,4 +352,4 @@ if ( \S::get( 'action' ) == 'domain_opr_save' )
 
   echo json_encode( ['result' => 'ok'] );
   exit;
-}
\ No newline at end of file
+}
diff --git a/docs/api-public-product-management.md b/docs/api-public-product-management.md
new file mode 100644
index 0000000..8a58370
--- /dev/null
+++ b/docs/api-public-product-management.md
@@ -0,0 +1,278 @@
+# AdsPRO API - Zarzadzanie produktami (publiczna dokumentacja)
+
+Ten dokument opisuje endpointy HTTP dostepne w `api.php` do zarzadzania danymi produktow.
+Format jest przygotowany pod integracje automatyczne (AI/agent/workflow).
+
+## 1. Informacje bazowe
+
+- Metoda: `GET` lub `POST` (`application/x-www-form-urlencoded` albo query string).
+- Endpoint bazowy: `https://TWOJA-DOMENA/api.php`
+- Parametr routingu: `action`
+- Odpowiedzi: JSON
+- Kodowanie: UTF-8
+
+Przyklady zakladaja, ze:
+- domena: `https://example.com`
+- klucz API: `YOUR_API_KEY`
+- klient: `client_id=12`
+- produkt: `offer_id=SKU-123`
+
+## 2. Autoryzacja
+
+Kazdy endpoint produktowy wymaga poprawnego parametru:
+
+- `api_key` - klucz porownywany z `settings.setting_key = api_key`
+
+Brak lub zly klucz zwraca:
+
+```json
+{
+  "result": "error",
+  "message": "Invalid api_key"
+}
+```
+
+HTTP status: `401`
+
+## 3. Wspolne parametry
+
+- `offer_id` (string, wymagany) - zewnetrzny identyfikator produktu.
+- `client_id` (int, wymagany) - lokalny identyfikator klienta.
+
+Jesli produkt nie istnieje dla pary `offer_id + client_id`, API zwraca:
+
+```json
+{
+  "result": "error",
+  "message": "Product not found"
+}
+```
+
+HTTP status: `404`
+
+## 4. Endpointy produktowe
+
+### 4.1 Ustawienie tytulu produktu
+
+- `action=product_title_set`
+- Cel: zapisuje `products.title`
+
+Parametry:
+- `api_key` (string, wymagany)
+- `offer_id` (string, wymagany)
+- `client_id` (int, wymagany)
+- `title` (string, opcjonalny)
+
+Uwagi:
+- `title` jest przycinany (`trim`).
+- Pusty `title` ustawia `products.title = NULL` (czyszczenie pola).
+- Zmiana zapisuje komentarz techniczny w `products_comments`.
+
+Przyklad:
+
+```bash
+curl -X POST "https://example.com/api.php" \
+  -d "action=product_title_set" \
+  -d "api_key=YOUR_API_KEY" \
+  -d "client_id=12" \
+  -d "offer_id=SKU-123" \
+  -d "title=Buty biegowe meskie Air Run 42"
+```
+
+Przyklad odpowiedzi:
+
+```json
+{
+  "result": "ok",
+  "product_id": 987,
+  "offer_id": "SKU-123",
+  "client_id": 12,
+  "title": "Buty biegowe meskie Air Run 42"
+}
+```
+
+### 4.2 Sprawdzenie, czy tytul byl zmieniony
+
+- `action=product_title_changed_check`
+- Cel: sprawdza, czy custom tytul rozni sie od bazowej nazwy produktu
+
+Logika pola `title_changed`:
+- `true` gdy `products.title` jest niepuste i inne niz `products.name`
+- `false` w pozostalych przypadkach
+
+Parametry:
+- `api_key` (string, wymagany)
+- `offer_id` (string, wymagany)
+- `client_id` (int, wymagany)
+
+Przyklad:
+
+```bash
+curl -G "https://example.com/api.php" \
+  --data-urlencode "action=product_title_changed_check" \
+  --data-urlencode "api_key=YOUR_API_KEY" \
+  --data-urlencode "client_id=12" \
+  --data-urlencode "offer_id=SKU-123"
+```
+
+Przyklad odpowiedzi:
+
+```json
+{
+  "result": "ok",
+  "product_id": 987,
+  "offer_id": "SKU-123",
+  "client_id": 12,
+  "title_changed": true,
+  "default_name": "Buty Air Run - wariant bazowy",
+  "custom_title": "Buty biegowe meskie Air Run 42"
+}
+```
+
+### 4.3 Ustawienie Google Product Category
+
+- `action=product_google_category_set`
+- Cel: zapisuje `products.google_product_category`
+
+Parametry:
+- `api_key` (string, wymagany)
+- `offer_id` (string, wymagany)
+- `client_id` (int, wymagany)
+- `google_product_category` (string, opcjonalny)
+
+Uwagi:
+- wartosc jest przycinana (`trim`)
+- pusta wartosc ustawia `NULL` (czyszczenie pola)
+- zmiana zapisuje komentarz techniczny w `products_comments`
+
+Przyklad:
+
+```bash
+curl -X POST "https://example.com/api.php" \
+  -d "action=product_google_category_set" \
+  -d "api_key=YOUR_API_KEY" \
+  -d "client_id=12" \
+  -d "offer_id=SKU-123" \
+  -d "google_product_category=Apparel & Accessories > Shoes"
+```
+
+Przyklad odpowiedzi:
+
+```json
+{
+  "result": "ok",
+  "product_id": 987,
+  "offer_id": "SKU-123",
+  "client_id": 12,
+  "google_product_category": "Apparel & Accessories > Shoes"
+}
+```
+
+### 4.4 Odczyt Google Product Category
+
+- `action=product_google_category_get`
+- Cel: odczytuje `products.google_product_category`
+
+Parametry:
+- `api_key` (string, wymagany)
+- `offer_id` (string, wymagany)
+- `client_id` (int, wymagany)
+
+Przyklad:
+
+```bash
+curl -G "https://example.com/api.php" \
+  --data-urlencode "action=product_google_category_get" \
+  --data-urlencode "api_key=YOUR_API_KEY" \
+  --data-urlencode "client_id=12" \
+  --data-urlencode "offer_id=SKU-123"
+```
+
+Przyklad odpowiedzi:
+
+```json
+{
+  "result": "ok",
+  "product_id": 987,
+  "offer_id": "SKU-123",
+  "client_id": 12,
+  "google_product_category": "Apparel & Accessories > Shoes"
+}
+```
+
+Jesli kategoria nie jest ustawiona:
+
+```json
+{
+  "result": "ok",
+  "product_id": 987,
+  "offer_id": "SKU-123",
+  "client_id": 12,
+  "google_product_category": null
+}
+```
+
+### 4.5 Ustawienie custom_label_4 (istniejacy endpoint)
+
+- `action=product_custom_label_4_set`
+- Cel: zapisuje `products.custom_label_4`
+
+Parametry:
+- `api_key` (string, wymagany)
+- `offer_id` (string, wymagany)
+- `client_id` (int, wymagany)
+- `custom_label_4` (string, opcjonalny)
+
+Przyklad:
+
+```bash
+curl -X POST "https://example.com/api.php" \
+  -d "action=product_custom_label_4_set" \
+  -d "api_key=YOUR_API_KEY" \
+  -d "client_id=12" \
+  -d "offer_id=SKU-123" \
+  -d "custom_label_4=bestseller"
+```
+
+Przyklad odpowiedzi:
+
+```json
+{
+  "result": "ok"
+}
+```
+
+## 5. Walidacja i bledy
+
+### 5.1 Brak wymaganych parametrow
+
+```json
+{
+  "result": "error",
+  "message": "Missing required params: offer_id, client_id"
+}
+```
+
+HTTP status: `422`
+
+### 5.2 Nieznana akcja
+
+`api.php` nie zwraca centralnego bledu dla nieznanej `action`.
+Przy integracji AI zawsze ustawiaj jawnie `action` i weryfikuj, czy odpowiedz to JSON.
+
+## 6. Zalecany kontrakt dla agentow AI
+
+- Zawsze wysylaj `api_key`, `action`, `client_id`, `offer_id`.
+- Po `product_title_set` od razu wywolaj `product_title_changed_check`.
+- Po `product_google_category_set` od razu wywolaj `product_google_category_get`.
+- Traktuj `null` jako brak wartosci.
+- Przy statusach `401`, `404`, `422` przerywaj workflow i zwracaj czytelny blad operatorowi.
+
+## 7. Minimalny scenariusz end-to-end
+
+1. Ustaw tytul (`product_title_set`)
+2. Potwierdz zmiane (`product_title_changed_check`)
+3. Ustaw kategorie (`product_google_category_set`)
+4. Odczytaj kategorie (`product_google_category_get`)
+
+To daje prosty, deterministyczny przeplyw dla automatyzacji AI.