diff --git a/examples/store/document-splitting.php b/examples/store/document-splitting.php
new file mode 100644
index 00000000..43029695
--- /dev/null
+++ b/examples/store/document-splitting.php
@@ -0,0 +1,16 @@
+<?php
+
+declare(strict_types=1);
+
+use PhpLlm\LlmChain\Store\Document\Loader\TextFileLoader;
+use PhpLlm\LlmChain\Store\Document\Transformer\TextSplitTransformer;
+
+require_once dirname(__DIR__, 2).'/vendor/autoload.php';
+
+$loader = new TextFileLoader();
+$splitter = new TextSplitTransformer();
+$source = dirname(__DIR__, 2).'/tests/Fixture/lorem.txt';
+
+$documents = iterator_to_array($splitter($loader($source)));
+
+dump($documents);
diff --git a/examples/store/document-vectorizing.php b/examples/store/document-vectorizing.php
new file mode 100644
index 00000000..186b1239
--- /dev/null
+++ b/examples/store/document-vectorizing.php
@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+use PhpLlm\LlmChain\Platform\Bridge\OpenAI\Embeddings;
+use PhpLlm\LlmChain\Platform\Bridge\OpenAI\PlatformFactory;
+use PhpLlm\LlmChain\Store\Document\TextDocument;
+use PhpLlm\LlmChain\Store\Document\VectorDocument;
+use PhpLlm\LlmChain\Store\Document\Vectorizer;
+use Symfony\Component\Dotenv\Dotenv;
+use Symfony\Component\Uid\Uuid;
+
+require_once dirname(__DIR__, 2).'/vendor/autoload.php';
+(new Dotenv())->loadEnv(dirname(__DIR__, 2).'/.env');
+
+if (empty($_ENV['OPENAI_API_KEY'])) {
+    echo 'Please set the OPENAI_API_KEY environment variable.'.\PHP_EOL;
+    exit(1);
+}
+
+$platform = PlatformFactory::create($_ENV['OPENAI_API_KEY']);
+$embeddings = new Embeddings(Embeddings::TEXT_3_LARGE);
+
+$textDocuments = [
+    new TextDocument(Uuid::v4(), 'Hello World'),
+    new TextDocument(Uuid::v4(), 'Lorem ipsum dolor sit amet'),
+    new TextDocument(Uuid::v4(), 'PHP Hypertext Preprocessor'),
+];
+
+$vectorizer = new Vectorizer($platform, $embeddings);
+$vectorDocuments = $vectorizer->vectorizeDocuments($textDocuments);
+
+dump(array_map(fn (VectorDocument $document) => $document->vector->getDimensions(), $vectorDocuments));
diff --git a/examples/store/mariadb-similarity-search-gemini.php b/examples/store/mariadb-similarity-search-gemini.php
index 3c29374f..25df7003 100644
--- a/examples/store/mariadb-similarity-search-gemini.php
+++ b/examples/store/mariadb-similarity-search-gemini.php
@@ -15,6 +15,7 @@
 use PhpLlm\LlmChain\Store\Bridge\MariaDB\Store;
 use PhpLlm\LlmChain\Store\Document\Metadata;
 use PhpLlm\LlmChain\Store\Document\TextDocument;
+use PhpLlm\LlmChain\Store\Document\Vectorizer;
 use PhpLlm\LlmChain\Store\Indexer;
 use Symfony\Component\Dotenv\Dotenv;
 use Symfony\Component\Uid\Uuid;
@@ -57,7 +58,8 @@
 // create embeddings for documents
 $platform = PlatformFactory::create($_ENV['GOOGLE_API_KEY']);
 $embeddings = new Embeddings(options: ['dimensions' => 768, 'task_type' => TaskType::SemanticSimilarity]);
-$indexer = new Indexer($platform, $embeddings, $store);
+$vectorizer = new Vectorizer($platform, $embeddings);
+$indexer = new Indexer($vectorizer, $store);
 $indexer->index($documents);
 
 $model = new Gemini(Gemini::GEMINI_2_FLASH_LITE);
diff --git a/examples/store/mariadb-similarity-search.php b/examples/store/mariadb-similarity-search.php
index 65332d59..b7e2cc93 100644
--- a/examples/store/mariadb-similarity-search.php
+++ b/examples/store/mariadb-similarity-search.php
@@ -14,6 +14,7 @@
 use PhpLlm\LlmChain\Store\Bridge\MariaDB\Store;
 use PhpLlm\LlmChain\Store\Document\Metadata;
 use PhpLlm\LlmChain\Store\Document\TextDocument;
+use PhpLlm\LlmChain\Store\Document\Vectorizer;
 use PhpLlm\LlmChain\Store\Indexer;
 use Symfony\Component\Dotenv\Dotenv;
 use Symfony\Component\Uid\Uuid;
@@ -55,7 +56,8 @@
 
 // create embeddings for documents
 $platform = PlatformFactory::create($_ENV['OPENAI_API_KEY']);
-$indexer = new Indexer($platform, $embeddings = new Embeddings(), $store);
+$vectorizer = new Vectorizer($platform, $embeddings = new Embeddings());
+$indexer = new Indexer($vectorizer, $store);
 $indexer->index($documents);
 
 $model = new GPT(GPT::GPT_4O_MINI);
diff --git a/examples/store/mongodb-similarity-search.php b/examples/store/mongodb-similarity-search.php
index c04cc30b..ed009e5e 100644
--- a/examples/store/mongodb-similarity-search.php
+++ b/examples/store/mongodb-similarity-search.php
@@ -13,6 +13,7 @@
 use PhpLlm\LlmChain\Store\Bridge\MongoDB\Store;
 use PhpLlm\LlmChain\Store\Document\Metadata;
 use PhpLlm\LlmChain\Store\Document\TextDocument;
+use PhpLlm\LlmChain\Store\Document\Vectorizer;
 use PhpLlm\LlmChain\Store\Indexer;
 use Symfony\Component\Dotenv\Dotenv;
 use Symfony\Component\Uid\Uuid;
@@ -52,7 +53,8 @@
 
 // create embeddings for documents
 $platform = PlatformFactory::create($_ENV['OPENAI_API_KEY']);
-$indexer = new Indexer($platform, $embeddings = new Embeddings(), $store);
+$vectorizer = new Vectorizer($platform, $embeddings = new Embeddings());
+$indexer = new Indexer($vectorizer, $store);
 $indexer->index($documents);
 
 // initialize the index
diff --git a/examples/store/pinecone-similarity-search.php b/examples/store/pinecone-similarity-search.php
index c9083da9..ad6b0c9c 100644
--- a/examples/store/pinecone-similarity-search.php
+++ b/examples/store/pinecone-similarity-search.php
@@ -12,6 +12,7 @@
 use PhpLlm\LlmChain\Store\Bridge\Pinecone\Store;
 use PhpLlm\LlmChain\Store\Document\Metadata;
 use PhpLlm\LlmChain\Store\Document\TextDocument;
+use PhpLlm\LlmChain\Store\Document\Vectorizer;
 use PhpLlm\LlmChain\Store\Indexer;
 use Probots\Pinecone\Pinecone;
 use Symfony\Component\Dotenv\Dotenv;
@@ -46,7 +47,8 @@
 
 // create embeddings for documents
 $platform = PlatformFactory::create($_ENV['OPENAI_API_KEY']);
-$indexer = new Indexer($platform, $embeddings = new Embeddings(), $store);
+$vectorizer = new Vectorizer($platform, $embeddings = new Embeddings());
+$indexer = new Indexer($vectorizer, $store);
 $indexer->index($documents);
 
 $model = new GPT(GPT::GPT_4O_MINI);
diff --git a/src/Store/Document/Loader/TextFileLoader.php b/src/Store/Document/Loader/TextFileLoader.php
new file mode 100644
index 00000000..af703f4d
--- /dev/null
+++ b/src/Store/Document/Loader/TextFileLoader.php
@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpLlm\LlmChain\Store\Document\Loader;
+
+use PhpLlm\LlmChain\Store\Document\LoaderInterface;
+use PhpLlm\LlmChain\Store\Document\Metadata;
+use PhpLlm\LlmChain\Store\Document\TextDocument;
+use PhpLlm\LlmChain\Store\Exception\RuntimeException;
+use Symfony\Component\Uid\Uuid;
+
+/**
+ * @author Christopher Hertel <mail@christopher-hertel.de>
+ */
+final readonly class TextFileLoader implements LoaderInterface
+{
+    public function __invoke(string $source, array $options = []): iterable
+    {
+        if (!is_file($source)) {
+            throw new RuntimeException(\sprintf('File "%s" does not exist.', $source));
+        }
+
+        $content = file_get_contents($source);
+
+        if (false === $content) {
+            throw new RuntimeException(\sprintf('Unable to read file "%s"', $source));
+        }
+
+        yield new TextDocument(Uuid::v4(), trim($content), new Metadata([
+            'source' => $source,
+        ]));
+    }
+}
diff --git a/src/Store/Document/LoaderInterface.php b/src/Store/Document/LoaderInterface.php
new file mode 100644
index 00000000..2e653785
--- /dev/null
+++ b/src/Store/Document/LoaderInterface.php
@@ -0,0 +1,19 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpLlm\LlmChain\Store\Document;
+
+/**
+ * @author Christopher Hertel <mail@christopher-hertel.de>
+ */
+interface LoaderInterface
+{
+    /**
+     * @param string               $source  Identifier for the loader to load the documents from, e.g. file path, folder, or URL.
+     * @param array<string, mixed> $options loader specific set of options to control the loading process
+     *
+     * @return iterable<TextDocument> iterable of TextDocuments loaded from the source
+     */
+    public function __invoke(string $source, array $options = []): iterable;
+}
diff --git a/src/Store/Document/Transformer/ChainTransformer.php b/src/Store/Document/Transformer/ChainTransformer.php
new file mode 100644
index 00000000..16ede042
--- /dev/null
+++ b/src/Store/Document/Transformer/ChainTransformer.php
@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpLlm\LlmChain\Store\Document\Transformer;
+
+use PhpLlm\LlmChain\Store\Document\TransformerInterface;
+
+final readonly class ChainTransformer implements TransformerInterface
+{
+    /**
+     * @var TransformerInterface[]
+     */
+    private array $transformers;
+
+    /**
+     * @param iterable<TransformerInterface> $transformers
+     */
+    public function __construct(iterable $transformers)
+    {
+        $this->transformers = $transformers instanceof \Traversable ? iterator_to_array($transformers) : $transformers;
+    }
+
+    public function __invoke(iterable $documents, array $options = []): iterable
+    {
+        foreach ($this->transformers as $transformer) {
+            $documents = $transformer($documents, $options);
+        }
+
+        return $documents;
+    }
+}
diff --git a/src/Store/Document/Transformer/ChunkDelayTransformer.php b/src/Store/Document/Transformer/ChunkDelayTransformer.php
new file mode 100644
index 00000000..2948379d
--- /dev/null
+++ b/src/Store/Document/Transformer/ChunkDelayTransformer.php
@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpLlm\LlmChain\Store\Document\Transformer;
+
+use PhpLlm\LlmChain\Store\Document\TransformerInterface;
+use Symfony\Component\Clock\ClockInterface;
+
+/**
+ * This transformer splits the batch of documents into chunks and delays in-between with x seconds, which is useful
+ * when indexing a lot of documents and facing API rate limits.
+ *
+ * @author Christopher Hertel <mail@christopher-hertel.de>
+ */
+final readonly class ChunkDelayTransformer implements TransformerInterface
+{
+    public const OPTION_CHUNK_SIZE = 'chunk_size';
+    public const OPTION_DELAY = 'delay';
+
+    public function __construct(
+        private ClockInterface $clock,
+    ) {
+    }
+
+    /**
+     * @param array{chunk_size?: int, delay?: int} $options
+     */
+    public function __invoke(iterable $documents, array $options = []): iterable
+    {
+        $chunkSize = $options[self::OPTION_CHUNK_SIZE] ?? 50;
+        $delay = $options[self::OPTION_DELAY] ?? 10;
+
+        $counter = 0;
+        foreach ($documents as $document) {
+            yield $document;
+            ++$counter;
+
+            if ($chunkSize === $counter && 0 !== $delay) {
+                $this->clock->sleep($delay);
+            }
+        }
+    }
+}
diff --git a/src/Store/Document/Transformer/TextSplitTransformer.php b/src/Store/Document/Transformer/TextSplitTransformer.php
new file mode 100644
index 00000000..60c2d624
--- /dev/null
+++ b/src/Store/Document/Transformer/TextSplitTransformer.php
@@ -0,0 +1,62 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpLlm\LlmChain\Store\Document\Transformer;
+
+use PhpLlm\LlmChain\Store\Document\Metadata;
+use PhpLlm\LlmChain\Store\Document\TextDocument;
+use PhpLlm\LlmChain\Store\Document\TransformerInterface;
+use PhpLlm\LlmChain\Store\Exception\InvalidArgumentException;
+use Symfony\Component\Uid\Uuid;
+
+/**
+ * Splits a TextDocument into smaller chunks of specified size with optional overlap.
+ * If the document's content is shorter than the specified chunk size, it returns the original document as a single chunk.
+ * Overlap cannot be negative and must be less than the chunk size.
+ *
+ * @author Christopher Hertel <mail@christopher-hertel.de>
+ */
+final readonly class TextSplitTransformer implements TransformerInterface
+{
+    public const OPTION_CHUNK_SIZE = 'chunk_size';
+    public const OPTION_OVERLAP = 'overlap';
+
+    /**
+     * @param array{chunk_size?: int, overlap?: int} $options
+     */
+    public function __invoke(iterable $documents, array $options = []): iterable
+    {
+        $chunkSize = $options[self::OPTION_CHUNK_SIZE] ?? 1000;
+        $overlap = $options[self::OPTION_OVERLAP] ?? 200;
+
+        if ($overlap < 0 || $overlap >= $chunkSize) {
+            throw new InvalidArgumentException('Overlap must be non-negative and less than chunk size.');
+        }
+
+        foreach ($documents as $document) {
+            if (mb_strlen($document->content) <= $chunkSize) {
+                yield $document;
+
+                continue;
+            }
+
+            $text = $document->content;
+            $length = mb_strlen($text);
+            $start = 0;
+
+            while ($start < $length) {
+                $end = min($start + $chunkSize, $length);
+                $chunkText = mb_substr($text, $start, $end - $start);
+
+                yield new TextDocument(Uuid::v4(), $chunkText, new Metadata([
+                    'parent_id' => $document->id,
+                    'text' => $chunkText,
+                    ...$document->metadata,
+                ]));
+
+                $start += ($chunkSize - $overlap);
+            }
+        }
+    }
+}
diff --git a/src/Store/Document/TransformerInterface.php b/src/Store/Document/TransformerInterface.php
new file mode 100644
index 00000000..76d8c965
--- /dev/null
+++ b/src/Store/Document/TransformerInterface.php
@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpLlm\LlmChain\Store\Document;
+
+/**
+ * A Transformer is designed to mutate a stream of TextDocuments with the purpose of preparing them for indexing.
+ * It can reduce or expand the number of documents, modify their content or metadata.
+ * It should not act blocking, but is expected to iterate over incoming documents and yield prepared ones.
+ *
+ * @author Christopher Hertel <mail@christopher-hertel.de>
+ */
+interface TransformerInterface
+{
+    /**
+     * @param iterable<TextDocument> $documents
+     * @param array<string, mixed>   $options
+     *
+     * @return iterable<TextDocument>
+     */
+    public function __invoke(iterable $documents, array $options = []): iterable;
+}
diff --git a/src/Store/Document/Vectorizer.php b/src/Store/Document/Vectorizer.php
new file mode 100644
index 00000000..e9f51b2f
--- /dev/null
+++ b/src/Store/Document/Vectorizer.php
@@ -0,0 +1,53 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpLlm\LlmChain\Store\Document;
+
+use PhpLlm\LlmChain\Platform\Capability;
+use PhpLlm\LlmChain\Platform\Model;
+use PhpLlm\LlmChain\Platform\PlatformInterface;
+
+/**
+ * The Vectorizer encapsulates the logic to convert a collection of TextDocuments into VectorDocuments. It checks for
+ * the model's capabilities to handle batch processing or handles it with HttpClient's concurrency feature.
+ */
+final readonly class Vectorizer
+{
+    public function __construct(
+        private PlatformInterface $platform,
+        private Model $model,
+    ) {
+    }
+
+    /**
+     * @param TextDocument[] $documents
+     *
+     * @return VectorDocument[]
+     */
+    public function vectorizeDocuments(array $documents): array
+    {
+        if ($this->model->supports(Capability::INPUT_MULTIPLE)) {
+            $response = $this->platform->request($this->model, array_map(fn (TextDocument $document) => $document->content, $documents));
+
+            $vectors = $response->getContent();
+        } else {
+            $responses = [];
+            foreach ($documents as $document) {
+                $responses[] = $this->platform->request($this->model, $document->content);
+            }
+
+            $vectors = [];
+            foreach ($responses as $response) {
+                $vectors = array_merge($vectors, $response->getContent());
+            }
+        }
+
+        $vectorDocuments = [];
+        foreach ($documents as $i => $document) {
+            $vectorDocuments[] = new VectorDocument($document->id, $vectors[$i], $document->metadata);
+        }
+
+        return $vectorDocuments;
+    }
+}
diff --git a/src/Store/Indexer.php b/src/Store/Indexer.php
index 8057c200..0f4f1bf3 100644
--- a/src/Store/Indexer.php
+++ b/src/Store/Indexer.php
@@ -4,87 +4,51 @@
 
 namespace PhpLlm\LlmChain\Store;
 
-use PhpLlm\LlmChain\Platform\Capability;
-use PhpLlm\LlmChain\Platform\Model;
-use PhpLlm\LlmChain\Platform\PlatformInterface;
 use PhpLlm\LlmChain\Store\Document\TextDocument;
-use PhpLlm\LlmChain\Store\Document\VectorDocument;
+use PhpLlm\LlmChain\Store\Document\Vectorizer;
 use Psr\Log\LoggerInterface;
 use Psr\Log\NullLogger;
-use Symfony\Component\Clock\Clock;
-use Symfony\Component\Clock\ClockInterface;
 
 /**
+ * Converts a collection of TextDocuments into VectorDocuments and pushes them to a store implementation.
+ *
  * @author Christopher Hertel <mail@christopher-hertel.de>
  */
 final readonly class Indexer
 {
-    private ClockInterface $clock;
-
     public function __construct(
-        private PlatformInterface $platform,
-        private Model $model,
+        private Vectorizer $vectorizer,
         private StoreInterface $store,
-        ?ClockInterface $clock = null,
         private LoggerInterface $logger = new NullLogger(),
     ) {
-        $this->clock = $clock ?? Clock::get();
     }
 
     /**
      * @param TextDocument|iterable<TextDocument> $documents
+     * @param int                                 $chunkSize number of documents to vectorize and store in one batch
      */
-    public function index(TextDocument|iterable $documents, int $chunkSize = 0, int $sleep = 0): void
+    public function index(TextDocument|iterable $documents, int $chunkSize = 50): void
     {
         if ($documents instanceof TextDocument) {
             $documents = [$documents];
         }
 
-        if ([] === $documents) {
-            $this->logger->debug('No documents to index');
-
-            return;
-        }
-
-        $chunks = 0 !== $chunkSize ? array_chunk($documents, $chunkSize) : [$documents];
-
-        foreach ($chunks as $chunk) {
-            $this->store->add(...$this->createVectorDocuments($chunk));
-
-            if (0 !== $sleep) {
-                $this->clock->sleep($sleep);
-            }
-        }
-    }
-
-    /**
-     * @param TextDocument[] $documents
-     *
-     * @return VectorDocument[]
-     */
-    private function createVectorDocuments(array $documents): array
-    {
-        if ($this->model->supports(Capability::INPUT_MULTIPLE)) {
-            $response = $this->platform->request($this->model, array_map(fn (TextDocument $document) => $document->content, $documents));
-
-            $vectors = $response->getContent();
-        } else {
-            $responses = [];
-            foreach ($documents as $document) {
-                $responses[] = $this->platform->request($this->model, $document->content);
-            }
+        $counter = 0;
+        $chunk = [];
+        foreach ($documents as $document) {
+            $chunk[] = $document;
+            ++$counter;
 
-            $vectors = [];
-            foreach ($responses as $response) {
-                $vectors = array_merge($vectors, $response->getContent());
+            if ($chunkSize === \count($chunk)) {
+                $this->store->add(...$this->vectorizer->vectorizeDocuments($chunk));
+                $chunk = [];
             }
         }
 
-        $vectorDocuments = [];
-        foreach ($documents as $i => $document) {
-            $vectorDocuments[] = new VectorDocument($document->id, $vectors[$i], $document->metadata);
+        if (\count($chunk) > 0) {
+            $this->store->add(...$this->vectorizer->vectorizeDocuments($chunk));
         }
 
-        return $vectorDocuments;
+        $this->logger->debug(0 === $counter ? 'No documents to index' : \sprintf('Indexed %d documents', $counter));
     }
 }
diff --git a/tests/Fixture/lorem.txt b/tests/Fixture/lorem.txt
new file mode 100644
index 00000000..a2600b83
--- /dev/null
+++ b/tests/Fixture/lorem.txt
@@ -0,0 +1,15 @@
+Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa.
+Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Donec quam felis,
+ultricies nec, pellentesque eu, pretium quis, sem. Nulla consequat massa quis enim. Donec pede justo,
+fringilla vel, aliquet nec, vulputate eget, arcu. In enim justo, rhoncus ut, imperdiet a, venenatis vitae,
+justo. Nullam dictum felis eu pede mollis pretium. Integer tincidunt. Cras dapibus. Vivamus elementum semper
+nisi. Aenean vulputate eleifend tellus. Aenean leo ligula, porttitor eu, consequat vitae, eleifend ac, enim.
+Aliquam lorem ante, dapibus in, viverra quis, feugiat a, tellus. Phasellus viverra nulla ut metus varius
+laoreet. Quisque rutrum. Aenean imperdiet. Etiam ultricies nisi vel augue. Curabitur ullamcorper ultricies
+nisi. Nam eget dui. Etiam rhoncus. Maecenas tempus, tellus eget condimentum rhoncus, sem quam semper libero,
+sit amet adipiscing sem neque sed ipsum. Nam quam nunc, blandit vel, luctus pulvinar, hendrerit id, lorem.
+Maecenas nec odio et ante tincidunt tempus. Donec vitae sapien ut libero venenatis faucibus. Nullam quis
+ante. Etiam sit amet orci eget eros faucibus tincidunt. Duis leo. Sed fringilla mauris sit amet nibh. Donec
+sodales sagittis magna. Sed consequat, leo eget bibendum sodales, augue velit cursus nunc, quis gravida
+magna mi a libero. Fusce vulputate eleifend sapien. Vestibulum purus quam, scelerisque ut, mollis sed,
+nonummy id, met
diff --git a/tests/Store/Document/Loader/TextFileLoaderTest.php b/tests/Store/Document/Loader/TextFileLoaderTest.php
new file mode 100644
index 00000000..c6224831
--- /dev/null
+++ b/tests/Store/Document/Loader/TextFileLoaderTest.php
@@ -0,0 +1,54 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpLlm\LlmChain\Tests\Store\Document\Loader;
+
+use PhpLlm\LlmChain\Store\Document\Loader\TextFileLoader;
+use PhpLlm\LlmChain\Store\Document\TextDocument;
+use PhpLlm\LlmChain\Store\Exception\RuntimeException;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+
+#[CoversClass(TextFileLoader::class)]
+final class TextFileLoaderTest extends TestCase
+{
+    #[Test]
+    public function loadWithInvalidSource(): void
+    {
+        $loader = new TextFileLoader();
+
+        self::expectException(RuntimeException::class);
+        self::expectExceptionMessage('File "/invalid/source.txt" does not exist.');
+
+        iterator_to_array($loader('/invalid/source.txt'));
+    }
+
+    #[Test]
+    public function loadWithValidSource(): void
+    {
+        $loader = new TextFileLoader();
+
+        $documents = iterator_to_array($loader(\dirname(__DIR__, 3).'/Fixture/lorem.txt'));
+
+        self::assertCount(1, $documents);
+        self::assertInstanceOf(TextDocument::class, $document = $documents[0]);
+        self::assertStringStartsWith('Lorem ipsum', $document->content);
+        self::assertStringEndsWith('nonummy id, met', $document->content);
+        self::assertSame(1500, \strlen($document->content));
+    }
+
+    #[Test]
+    public function sourceIsPresentInMetadata(): void
+    {
+        $loader = new TextFileLoader();
+
+        $source = \dirname(__DIR__, 3).'/Fixture/lorem.txt';
+        $documents = iterator_to_array($loader($source));
+
+        self::assertCount(1, $documents);
+        self::assertInstanceOf(TextDocument::class, $document = $documents[0]);
+        self::assertSame($source, $document->metadata['source']);
+    }
+}
diff --git a/tests/Store/Document/Transformer/ChainTransformerTest.php b/tests/Store/Document/Transformer/ChainTransformerTest.php
new file mode 100644
index 00000000..58887484
--- /dev/null
+++ b/tests/Store/Document/Transformer/ChainTransformerTest.php
@@ -0,0 +1,60 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpLlm\LlmChain\Tests\Store\Document\Transformer;
+
+use PhpLlm\LlmChain\Store\Document\TextDocument;
+use PhpLlm\LlmChain\Store\Document\Transformer\ChainTransformer;
+use PhpLlm\LlmChain\Store\Document\TransformerInterface;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Uid\Uuid;
+
+#[CoversClass(TransformerInterface::class)]
+final class ChainTransformerTest extends TestCase
+{
+    #[Test]
+    public function chainTransformerAppliesAllTransformersInOrder(): void
+    {
+        $transformerA = new class implements TransformerInterface {
+            public function __invoke(iterable $documents, array $options = []): iterable
+            {
+                foreach ($documents as $document) {
+                    yield new TextDocument($document->id, $document->content.'-A');
+                }
+            }
+        };
+
+        $transformerB = new class implements TransformerInterface {
+            public function __invoke(iterable $documents, array $options = []): iterable
+            {
+                foreach ($documents as $document) {
+                    yield new TextDocument($document->id, $document->content.'-B');
+                }
+            }
+        };
+
+        $chain = new ChainTransformer([$transformerA, $transformerB]);
+        $documents = [
+            new TextDocument(Uuid::v4(), 'foo'),
+            new TextDocument(Uuid::v4(), 'bar'),
+        ];
+
+        $result = iterator_to_array($chain->__invoke($documents));
+
+        self::assertSame('foo-A-B', $result[0]->content);
+        self::assertSame('bar-A-B', $result[1]->content);
+    }
+
+    public function testChainTransformerWithNoTransformersReturnsInput(): void
+    {
+        $chain = new ChainTransformer([]);
+        $documents = [new TextDocument(Uuid::v4(), 'baz')];
+
+        $result = iterator_to_array($chain->__invoke($documents));
+
+        self::assertSame('baz', $result[0]->content);
+    }
+}
diff --git a/tests/Store/Document/Transformer/TextSplitTransformerTest.php b/tests/Store/Document/Transformer/TextSplitTransformerTest.php
new file mode 100644
index 00000000..52fe46b5
--- /dev/null
+++ b/tests/Store/Document/Transformer/TextSplitTransformerTest.php
@@ -0,0 +1,195 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpLlm\LlmChain\Tests\Store\Document\Transformer;
+
+use PhpLlm\LlmChain\Store\Document\Metadata;
+use PhpLlm\LlmChain\Store\Document\TextDocument;
+use PhpLlm\LlmChain\Store\Document\Transformer\TextSplitTransformer;
+use PhpLlm\LlmChain\Store\Exception\InvalidArgumentException;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Uid\Uuid;
+
+#[CoversClass(TextSplitTransformer::class)]
+final class TextSplitTransformerTest extends TestCase
+{
+    private TextSplitTransformer $transformer;
+
+    protected function setUp(): void
+    {
+        $this->transformer = new TextSplitTransformer();
+    }
+
+    #[Test]
+    public function splitReturnsSingleChunkForShortText(): void
+    {
+        $document = new TextDocument(Uuid::v4(), 'short text');
+
+        $chunks = iterator_to_array(($this->transformer)([$document]));
+
+        self::assertCount(1, $chunks);
+        self::assertSame('short text', $chunks[0]->content);
+    }
+
+    #[Test]
+    public function textLength(): void
+    {
+        self::assertSame(1500, mb_strlen($this->getLongText()));
+    }
+
+    #[Test]
+    public function splitSplitsLongTextWithOverlap(): void
+    {
+        $document = new TextDocument(Uuid::v4(), $this->getLongText());
+
+        $chunks = iterator_to_array(($this->transformer)([$document]));
+
+        self::assertCount(2, $chunks);
+
+        self::assertSame(1000, mb_strlen($chunks[0]->content));
+        self::assertSame(substr($this->getLongText(), 0, 1000), $chunks[0]->content);
+
+        self::assertSame(700, mb_strlen($chunks[1]->content));
+        self::assertSame(substr($this->getLongText(), 800, 700), $chunks[1]->content);
+    }
+
+    #[Test]
+    public function splitWithCustomChunkSizeAndOverlap(): void
+    {
+        $document = new TextDocument(Uuid::v4(), $this->getLongText());
+
+        $chunks = iterator_to_array(($this->transformer)([$document], [
+            TextSplitTransformer::OPTION_CHUNK_SIZE => 150,
+            TextSplitTransformer::OPTION_OVERLAP => 25,
+        ]));
+
+        self::assertCount(12, $chunks);
+
+        self::assertSame(150, mb_strlen($chunks[0]->content));
+        self::assertSame(substr($this->getLongText(), 0, 150), $chunks[0]->content);
+
+        self::assertSame(150, mb_strlen($chunks[1]->content));
+        self::assertSame(substr($this->getLongText(), 125, 150), $chunks[1]->content);
+
+        self::assertSame(150, mb_strlen($chunks[2]->content));
+        self::assertSame(substr($this->getLongText(), 250, 150), $chunks[2]->content);
+
+        self::assertSame(150, mb_strlen($chunks[3]->content));
+        self::assertSame(substr($this->getLongText(), 375, 150), $chunks[3]->content);
+
+        self::assertSame(150, mb_strlen($chunks[4]->content));
+        self::assertSame(substr($this->getLongText(), 500, 150), $chunks[4]->content);
+
+        self::assertSame(150, mb_strlen($chunks[5]->content));
+        self::assertSame(substr($this->getLongText(), 625, 150), $chunks[5]->content);
+
+        self::assertSame(150, mb_strlen($chunks[6]->content));
+        self::assertSame(substr($this->getLongText(), 750, 150), $chunks[6]->content);
+
+        self::assertSame(150, mb_strlen($chunks[7]->content));
+        self::assertSame(substr($this->getLongText(), 875, 150), $chunks[7]->content);
+
+        self::assertSame(150, mb_strlen($chunks[8]->content));
+        self::assertSame(substr($this->getLongText(), 1000, 150), $chunks[8]->content);
+
+        self::assertSame(150, mb_strlen($chunks[9]->content));
+        self::assertSame(substr($this->getLongText(), 1125, 150), $chunks[9]->content);
+
+        self::assertSame(150, mb_strlen($chunks[10]->content));
+        self::assertSame(substr($this->getLongText(), 1250, 150), $chunks[10]->content);
+
+        self::assertSame(125, mb_strlen($chunks[11]->content));
+        self::assertSame(substr($this->getLongText(), 1375, 150), $chunks[11]->content);
+    }
+
+    #[Test]
+    public function splitWithZeroOverlap(): void
+    {
+        $document = new TextDocument(Uuid::v4(), $this->getLongText());
+
+        $chunks = iterator_to_array(($this->transformer)([$document], [
+            TextSplitTransformer::OPTION_OVERLAP => 0,
+        ]));
+
+        self::assertCount(2, $chunks);
+        self::assertSame(substr($this->getLongText(), 0, 1000), $chunks[0]->content);
+        self::assertSame(substr($this->getLongText(), 1000, 500), $chunks[1]->content);
+    }
+
+    #[Test]
+    public function parentIdIsSetInMetadata(): void
+    {
+        $document = new TextDocument(Uuid::v4(), $this->getLongText());
+
+        $chunks = iterator_to_array(($this->transformer)([$document], [
+            TextSplitTransformer::OPTION_CHUNK_SIZE => 1000,
+            TextSplitTransformer::OPTION_OVERLAP => 200,
+        ]));
+
+        self::assertCount(2, $chunks);
+        self::assertSame($document->id, $chunks[0]->metadata['parent_id']);
+        self::assertSame($document->id, $chunks[1]->metadata['parent_id']);
+    }
+
+    #[Test]
+    public function metadataIsInherited(): void
+    {
+        $document = new TextDocument(Uuid::v4(), $this->getLongText(), new Metadata([
+            'key' => 'value',
+            'foo' => 'bar',
+        ]));
+
+        $chunks = iterator_to_array(($this->transformer)([$document]));
+
+        self::assertCount(2, $chunks);
+        self::assertSame('value', $chunks[0]->metadata['key']);
+        self::assertSame('bar', $chunks[0]->metadata['foo']);
+        self::assertSame('value', $chunks[1]->metadata['key']);
+        self::assertSame('bar', $chunks[1]->metadata['foo']);
+    }
+
+    #[Test]
+    public function splitWithChunkSizeLargerThanText(): void
+    {
+        $document = new TextDocument(Uuid::v4(), 'tiny');
+
+        $chunks = iterator_to_array(($this->transformer)([$document]));
+
+        self::assertCount(1, $chunks);
+        self::assertSame('tiny', $chunks[0]->content);
+    }
+
+    #[Test]
+    public function splitWithOverlapGreaterThanChunkSize(): void
+    {
+        $document = new TextDocument(Uuid::v4(), 'Abcdefg', new Metadata([]));
+        self::expectException(InvalidArgumentException::class);
+        self::expectExceptionMessage('Overlap must be non-negative and less than chunk size.');
+
+        iterator_to_array(($this->transformer)([$document], [
+            TextSplitTransformer::OPTION_CHUNK_SIZE => 10,
+            TextSplitTransformer::OPTION_OVERLAP => 20,
+        ]));
+    }
+
+    #[Test]
+    public function splitWithNegativeOverlap(): void
+    {
+        $document = new TextDocument(Uuid::v4(), 'Abcdefg', new Metadata([]));
+        self::expectException(InvalidArgumentException::class);
+        self::expectExceptionMessage('Overlap must be non-negative and less than chunk size.');
+
+        iterator_to_array(($this->transformer)([$document], [
+            TextSplitTransformer::OPTION_CHUNK_SIZE => 10,
+            TextSplitTransformer::OPTION_OVERLAP => -1,
+        ]));
+    }
+
+    private function getLongText(): string
+    {
+        return trim(file_get_contents(\dirname(__DIR__, 3).'/Fixture/lorem.txt'));
+    }
+}
diff --git a/tests/Store/IndexerTest.php b/tests/Store/IndexerTest.php
index 83e1a060..c267c06b 100644
--- a/tests/Store/IndexerTest.php
+++ b/tests/Store/IndexerTest.php
@@ -14,6 +14,7 @@
 use PhpLlm\LlmChain\Store\Document\Metadata;
 use PhpLlm\LlmChain\Store\Document\TextDocument;
 use PhpLlm\LlmChain\Store\Document\VectorDocument;
+use PhpLlm\LlmChain\Store\Document\Vectorizer;
 use PhpLlm\LlmChain\Store\Indexer;
 use PhpLlm\LlmChain\Tests\Double\PlatformTestHandler;
 use PhpLlm\LlmChain\Tests\Double\TestStore;
@@ -23,7 +24,6 @@
 use PHPUnit\Framework\Attributes\UsesClass;
 use PHPUnit\Framework\TestCase;
 use Psr\Log\LoggerInterface;
-use Symfony\Component\Clock\MockClock;
 use Symfony\Component\Uid\Uuid;
 
 #[CoversClass(Indexer::class)]
@@ -40,18 +40,13 @@
 final class IndexerTest extends TestCase
 {
     #[Test]
-    public function embedSingleDocument(): void
+    public function indexSingleDocument(): void
     {
         $document = new TextDocument($id = Uuid::v4(), 'Test content');
         $vector = new Vector([0.1, 0.2, 0.3]);
+        $vectorizer = new Vectorizer(PlatformTestHandler::createPlatform(new VectorResponse($vector)), new Embeddings());
 
-        $indexer = new Indexer(
-            PlatformTestHandler::createPlatform(new VectorResponse($vector)),
-            new Embeddings(),
-            $store = new TestStore(),
-            new MockClock(),
-        );
-
+        $indexer = new Indexer($vectorizer, $store = new TestStore());
         $indexer->index($document);
 
         self::assertCount(1, $store->documents);
@@ -61,38 +56,27 @@ public function embedSingleDocument(): void
     }
 
     #[Test]
-    public function embedEmptyDocumentList(): void
+    public function indexEmptyDocumentList(): void
     {
         $logger = self::createMock(LoggerInterface::class);
         $logger->expects(self::once())->method('debug')->with('No documents to index');
+        $vectorizer = new Vectorizer(PlatformTestHandler::createPlatform(), new Embeddings());
 
-        $indexer = new Indexer(
-            PlatformTestHandler::createPlatform(),
-            new Embeddings(),
-            $store = new TestStore(),
-            new MockClock(),
-            $logger,
-        );
-
+        $indexer = new Indexer($vectorizer, $store = new TestStore(), $logger);
         $indexer->index([]);
 
         self::assertSame([], $store->documents);
     }
 
     #[Test]
-    public function embedDocumentWithMetadata(): void
+    public function indexDocumentWithMetadata(): void
     {
         $metadata = new Metadata(['key' => 'value']);
         $document = new TextDocument($id = Uuid::v4(), 'Test content', $metadata);
         $vector = new Vector([0.1, 0.2, 0.3]);
+        $vectorizer = new Vectorizer(PlatformTestHandler::createPlatform(new VectorResponse($vector)), new Embeddings());
 
-        $indexer = new Indexer(
-            PlatformTestHandler::createPlatform(new VectorResponse($vector)),
-            new Embeddings(),
-            $store = new TestStore(),
-            new MockClock(),
-        );
-
+        $indexer = new Indexer($vectorizer, $store = new TestStore());
         $indexer->index($document);
 
         self::assertSame(1, $store->addCalls);
@@ -102,30 +86,4 @@ public function embedDocumentWithMetadata(): void
         self::assertSame($vector, $store->documents[0]->vector);
         self::assertSame(['key' => 'value'], $store->documents[0]->metadata->getArrayCopy());
     }
-
-    #[Test]
-    public function embedWithSleep(): void
-    {
-        $vector1 = new Vector([0.1, 0.2, 0.3]);
-        $vector2 = new Vector([0.4, 0.5, 0.6]);
-
-        $document1 = new TextDocument(Uuid::v4(), 'Test content 1');
-        $document2 = new TextDocument(Uuid::v4(), 'Test content 2');
-
-        $indexer = new Indexer(
-            PlatformTestHandler::createPlatform(new VectorResponse($vector1, $vector2)),
-            new Embeddings(),
-            $store = new TestStore(),
-            $clock = new MockClock('2024-01-01 00:00:00'),
-        );
-
-        $indexer->index(
-            documents: [$document1, $document2],
-            sleep: 3
-        );
-
-        self::assertSame(1, $store->addCalls);
-        self::assertCount(2, $store->documents);
-        self::assertSame('2024-01-01 00:00:03', $clock->now()->format('Y-m-d H:i:s'));
-    }
 }