diff --git a/src/core/etl/src/Flow/ETL/Loader/TransformerLoader.php b/src/core/etl/src/Flow/ETL/Loader/TransformerLoader.php
index 1d8433cca..233eb7141 100644
--- a/src/core/etl/src/Flow/ETL/Loader/TransformerLoader.php
+++ b/src/core/etl/src/Flow/ETL/Loader/TransformerLoader.php
@@ -25,12 +25,10 @@ public function closure(FlowContext $context) : void
     public function load(Rows $rows, FlowContext $context) : void
     {
         if ($this->transformer instanceof Transformer) {
-            $rows = $this->transformer->transform($rows, $context);
+            $this->loader->load($this->transformer->transform($rows, $context), $context);
         } else {
-            $rows = df()->from(from_rows($rows))->with($this->transformer)->fetch();
+            df($context->config)->from(from_rows($rows))->with($this->transformer)->load($this->loader)->run();
         }
-
-        $this->loader->load($rows, $context);
     }
 
     public function loaders() : array
diff --git a/src/core/etl/tests/Flow/ETL/Tests/Integration/Loader/TransformerLoaderTest.php b/src/core/etl/tests/Flow/ETL/Tests/Integration/Loader/TransformerLoaderTest.php
new file mode 100644
index 000000000..53420e466
--- /dev/null
+++ b/src/core/etl/tests/Flow/ETL/Tests/Integration/Loader/TransformerLoaderTest.php
@@ -0,0 +1,173 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Flow\ETL\Tests\Integration\Loader;
+
+use function Flow\ETL\DSL\{add_row_index, batch_size, df, drop, from_array, limit, mask_columns, select, to_memory, to_transformation};
+use Flow\ETL\Loader;
+use Flow\ETL\Memory\ArrayMemory;
+use Flow\ETL\Tests\Double\FakeStaticOrdersExtractor;
+use Flow\ETL\Tests\FlowTestCase;
+use Flow\ETL\Transformation\AddRowIndex\StartFrom;
+
+final class TransformerLoaderTest extends FlowTestCase
+{
+    public function test_transformer_loader_with_add_row_index_transformation() : void
+    {
+        $memory = new ArrayMemory();
+
+        df()
+            ->read(from_array([
+                ['name' => 'Alice', 'age' => 30],
+                ['name' => 'Bob', 'age' => 25],
+                ['name' => 'Charlie', 'age' => 35],
+            ]))
+            ->collect()
+            ->write(
+                to_transformation(
+                    add_row_index('row_num', StartFrom::ONE),
+                    to_memory($memory)
+                )
+            )
+            ->run();
+
+        self::assertSame(
+            [
+                ['name' => 'Alice', 'age' => 30, 'row_num' => 1],
+                ['name' => 'Bob', 'age' => 25, 'row_num' => 2],
+                ['name' => 'Charlie', 'age' => 35, 'row_num' => 3],
+            ],
+            $memory->dump()
+        );
+    }
+
+    public function test_transformer_loader_with_batch_size_transformation() : void
+    {
+        $loader = $this->createMock(Loader::class);
+        $loader->expects(self::exactly(2))
+            ->method('load');
+
+        df()
+             ->read(
+                 new FakeStaticOrdersExtractor(1000)
+             )
+             ->collect()
+             ->write(
+                 to_transformation(
+                     batch_size(500),
+                     $loader
+                 )
+             )
+             ->run();
+    }
+
+    public function test_transformer_loader_with_drop_transformation() : void
+    {
+        $memory = new ArrayMemory();
+
+        df()
+            ->read(from_array([
+                ['id' => 1, 'name' => 'Alice', 'email' => 'alice@example.com', 'password' => 'secret123'],
+                ['id' => 2, 'name' => 'Bob', 'email' => 'bob@example.com', 'password' => 'secret456'],
+            ]))
+            ->write(
+                to_transformation(
+                    drop('password', 'email'),
+                    to_memory($memory)
+                )
+            )
+            ->run();
+
+        self::assertSame(
+            [
+                ['id' => 1, 'name' => 'Alice'],
+                ['id' => 2, 'name' => 'Bob'],
+            ],
+            $memory->dump()
+        );
+    }
+
+    public function test_transformer_loader_with_limit_transformation() : void
+    {
+        $memory = new ArrayMemory();
+
+        df()
+            ->read(from_array([
+                ['id' => 1, 'name' => 'Alice'],
+                ['id' => 2, 'name' => 'Bob'],
+                ['id' => 3, 'name' => 'Charlie'],
+                ['id' => 4, 'name' => 'Diana'],
+                ['id' => 5, 'name' => 'Eve'],
+            ]))
+            ->collect()
+            ->write(
+                to_transformation(
+                    limit(3),
+                    to_memory($memory)
+                )
+            )
+            ->run();
+
+        self::assertSame(
+            [
+                ['id' => 1, 'name' => 'Alice'],
+                ['id' => 2, 'name' => 'Bob'],
+                ['id' => 3, 'name' => 'Charlie'],
+            ],
+            $memory->dump()
+        );
+    }
+
+    public function test_transformer_loader_with_mask_columns_transformation() : void
+    {
+        $memory = new ArrayMemory();
+
+        df()
+            ->read(from_array([
+                ['id' => 1, 'name' => 'Alice', 'ssn' => '123-45-6789', 'email' => 'alice@example.com'],
+                ['id' => 2, 'name' => 'Bob', 'ssn' => '987-65-4321', 'email' => 'bob@example.com'],
+            ]))
+            ->write(
+                to_transformation(
+                    mask_columns(['ssn', 'email'], '***'),
+                    to_memory($memory)
+                )
+            )
+            ->run();
+
+        self::assertSame(
+            [
+                ['id' => 1, 'name' => 'Alice', 'ssn' => '***', 'email' => '***'],
+                ['id' => 2, 'name' => 'Bob', 'ssn' => '***', 'email' => '***'],
+            ],
+            $memory->dump()
+        );
+    }
+
+    public function test_transformer_loader_with_select_transformation() : void
+    {
+        $memory = new ArrayMemory();
+
+        df()
+            ->read(from_array([
+                ['id' => 1, 'name' => 'Alice', 'email' => 'alice@example.com', 'age' => 30],
+                ['id' => 2, 'name' => 'Bob', 'email' => 'bob@example.com', 'age' => 25],
+            ]))
+            ->write(
+                to_transformation(
+                    select('name', 'email'),
+                    to_memory($memory)
+                )
+            )
+            ->run();
+
+        self::assertSame(
+            [
+                ['name' => 'Alice', 'email' => 'alice@example.com'],
+                ['name' => 'Bob', 'email' => 'bob@example.com'],
+            ],
+            $memory->dump()
+        );
+    }
+}
diff --git a/src/core/etl/tests/Flow/ETL/Tests/Unit/Loader/TransformerLoaderTest.php b/src/core/etl/tests/Flow/ETL/Tests/Unit/Loader/TransformerLoaderTest.php
index 3a9fec52d..c8352a60f 100644
--- a/src/core/etl/tests/Flow/ETL/Tests/Unit/Loader/TransformerLoaderTest.php
+++ b/src/core/etl/tests/Flow/ETL/Tests/Unit/Loader/TransformerLoaderTest.php
@@ -7,9 +7,7 @@
 use function Flow\ETL\DSL\{config, df, flow_context, from_array, ref, rows, to_memory, to_transformation};
 use function Flow\Types\DSL\type_string;
 use Flow\ETL\{DataFrame,
-    FlowContext,
     Loader,
-    Loader\Closure,
     Memory\ArrayMemory,
     Tests\FlowTestCase,
     Transformation,
@@ -36,44 +34,6 @@ public function test_transformer_loader() : void
         $transformer->load(rows(), flow_context(config()));
     }
 
-    /**
-     * Tests that the closure method is called when using a Closure loader.
-     */
-    public function test_transformer_loader_with_closure() : void
-    {
-        $closure_loader = $this->createMockForIntersectionOfInterfaces([Loader::class, Closure::class]);
-
-        $closure_loader->expects(self::once())
-            ->method('closure')
-            ->with(self::isInstanceOf(FlowContext::class));
-
-        \assert($closure_loader instanceof Loader);
-        $transformer = to_transformation(
-            new class implements Transformation {
-                public function transform(DataFrame $data_frame) : DataFrame
-                {
-                    return $data_frame;
-                }
-            },
-            $closure_loader
-        );
-
-        df()
-            ->read(
-                from_array(
-                    [
-                        ['id' => 1],
-                        ['id' => 2],
-                        ['id' => 3],
-                    ]
-                )
-            )
-            ->write(
-                $transformer
-            )
-            ->run();
-    }
-
     public function test_transformer_loader_with_transformation() : void
     {
         df()