diff --git a/api/index.php b/api/index.php
index 23bfb5b..7786135 100644
--- a/api/index.php
+++ b/api/index.php
@@ -1000,6 +1000,18 @@ try {
         case 'recipe_library_toggle_favorite':
             recipeLibraryToggleFavorite($db);
             break;
+        case 'recipe_tags_list':
+            recipeTagsList($db);
+            break;
+        case 'recipe_tags_add':
+            recipeTagsAdd($db);
+            break;
+        case 'recipe_tags_remove':
+            recipeTagsRemove($db);
+            break;
+        case 'recipe_tags_update':
+            recipeTagsUpdate($db);
+            break;
         case 'recipes_list':
             recipesList($db);
             break;
@@ -12404,6 +12416,90 @@ function recipeLibraryToggleFavorite(PDO $db): void {
     echo json_encode(['success' => true, 'is_favorite' => (bool)$fav]);
 }
 
+function recipeTagsList(PDO $db): void {
+    $rows = $db->query("SELECT id, key, label, icon, sort_order FROM recipe_tags ORDER BY sort_order ASC, id ASC")->fetchAll();
+    echo json_encode(['success' => true, 'tags' => $rows]);
+}
+
+function recipeTagsAdd(PDO $db): void {
+    $input = json_decode(file_get_contents('php://input'), true) ?? [];
+    $label = trim($input['label'] ?? '');
+    $icon  = trim($input['icon'] ?? '🏷️');
+
+    if ($label === '') {
+        echo json_encode(['success' => false, 'error' => 'label required']);
+        return;
+    }
+
+    $key = mb_strtolower(trim($label));
+    $key = preg_replace('/[^a-z0-9]+/u', '_', $key);
+    $key = trim($key, '_');
+    if ($key === '') {
+        echo json_encode(['success' => false, 'error' => 'invalid label']);
+        return;
+    }
+
+    $stmt = $db->prepare("SELECT id FROM recipe_tags WHERE key = ?");
+    $stmt->execute([$key]);
+    if ($stmt->fetch()) {
+        echo json_encode(['success' => false, 'error' => 'tag already exists']);
+        return;
+    }
+
+    $maxOrder = (int)$db->query("SELECT COALESCE(MAX(sort_order), 0) FROM recipe_tags")->fetchColumn();
+
+    $stmt = $db->prepare("INSERT INTO recipe_tags (key, label, icon, sort_order) VALUES (?, ?, ?, ?)");
+    $stmt->execute([$key, $label, $icon, $maxOrder + 1]);
+
+    echo json_encode(['success' => true, 'key' => $key]);
+}
+
+function recipeTagsRemove(PDO $db): void {
+    $input = json_decode(file_get_contents('php://input'), true) ?? [];
+    $key = trim($input['key'] ?? '');
+
+    if ($key === '') {
+        echo json_encode(['success' => false, 'error' => 'key required']);
+        return;
+    }
+
+    $rows = $db->query("SELECT recipe_json FROM recipe_library")->fetchAll(PDO::FETCH_COLUMN);
+    foreach ($rows as $json) {
+        $data = json_decode($json, true);
+        if (in_array($key, $data['tags'] ?? [], true)) {
+            echo json_encode(['success' => false, 'error' => 'tag still used by a recipe']);
+            return;
+        }
+    }
+
+    $db->prepare("DELETE FROM recipe_tags WHERE key = ?")->execute([$key]);
+    echo json_encode(['success' => true]);
+}
+
+function recipeTagsUpdate(PDO $db): void {
+    $input = json_decode(file_get_contents('php://input'), true) ?? [];
+    $key   = trim($input['key'] ?? '');
+    $label = trim($input['label'] ?? '');
+    $icon  = trim($input['icon'] ?? '');
+
+    if ($key === '' || $label === '') {
+        echo json_encode(['success' => false, 'error' => 'key and label required']);
+        return;
+    }
+
+    $stmt = $db->prepare("SELECT id FROM recipe_tags WHERE key = ?");
+    $stmt->execute([$key]);
+    if (!$stmt->fetch()) {
+        echo json_encode(['success' => false, 'error' => 'tag not found']);
+        return;
+    }
+
+    $stmt = $db->prepare("UPDATE recipe_tags SET label = ?, icon = ? WHERE key = ?");
+    $stmt->execute([$label, $icon ?: '🏷️', $key]);
+
+    echo json_encode(['success' => true]);
+}
+
 // ===== SHARED APP DATA FUNCTIONS =====
 
 function appSettingsGet(PDO $db): void {