diff --git a/core/lib/Http/Response/StreamedNdJsonResponse.php b/core/lib/Http/Response/StreamedNdJsonResponse.php
new file mode 100644
index 0000000..dd0429a
--- /dev/null
+++ b/core/lib/Http/Response/StreamedNdJsonResponse.php
@@ -0,0 +1,76 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace KTXC\Http\Response;
+
+/**
+ * StreamedNdJsonResponse streams an HTTP response as Newline Delimited JSON (NDJSON).
+ *
+ * Each item yielded by the provided iterable is serialized as a single JSON value
+ * followed by a newline character (\n). The response is flushed to the client every
+ * $flushInterval items so consumers can process records incrementally without waiting
+ * for the full payload.
+ *
+ * Content-Type is set to `application/x-ndjson` and `X-Accel-Buffering: no` is added
+ * by default to disable nginx proxy buffering.
+ *
+ * Example usage:
+ *
+ *     function records(): \Generator {
+ *         yield ['id' => 1, 'name' => 'Alice'];
+ *         yield ['id' => 2, 'name' => 'Bob'];
+ *     }
+ *
+ *     return new StreamedNdJsonResponse(records());
+ */
+class StreamedNdJsonResponse extends StreamedResponse
+{
+    /**
+     * @param iterable<mixed>                $items          Items to serialize; each becomes one JSON line
+     * @param int                            $flushInterval  Flush to client after this many items (default 10)
+     * @param int                            $status         HTTP status code (default 200)
+     * @param array<string, string|string[]> $headers        Additional HTTP headers
+     * @param int                            $encodingOptions Flags passed to json_encode()
+     */
+    public function __construct(
+        iterable $items,
+        int $flushInterval = 10,
+        int $status = 200,
+        array $headers = [],
+        private readonly int $encodingOptions = JsonResponse::DEFAULT_ENCODING_OPTIONS,
+    ) {
+        parent::__construct(null, $status, $headers);
+
+        if (!$this->headers->get('Content-Type')) {
+            $this->headers->set('Content-Type', 'application/x-ndjson');
+        }
+
+        if (!$this->headers->has('X-Accel-Buffering')) {
+            $this->headers->set('X-Accel-Buffering', 'no');
+        }
+
+        $encodingOptions = $this->encodingOptions;
+
+        $this->setCallback(static function () use ($items, $flushInterval, $encodingOptions): void {
+            $count = 0;
+
+            foreach ($items as $item) {
+                echo json_encode($item, \JSON_THROW_ON_ERROR | $encodingOptions) . "\n";
+                $count++;
+
+                if ($count >= $flushInterval) {
+                    @ob_flush();
+                    flush();
+                    $count = 0;
+                }
+            }
+
+            // final flush for any remaining buffered items
+            if ($count > 0) {
+                @ob_flush();
+                flush();
+            }
+        });
+    }
+}
diff --git a/shared/lib/Mail/Service/ServiceBaseInterface.php b/shared/lib/Mail/Service/ServiceBaseInterface.php
index 4de6e5c..9745c4b 100644
--- a/shared/lib/Mail/Service/ServiceBaseInterface.php
+++ b/shared/lib/Mail/Service/ServiceBaseInterface.php
@@ -9,6 +9,7 @@ declare(strict_types=1);
 
 namespace KTXF\Mail\Service;
 
+use Generator;
 use KTXF\Mail\Collection\CollectionBaseInterface;
 use KTXF\Mail\Object\AddressInterface;
 use KTXF\Resource\Delta\Delta;
@@ -168,6 +169,21 @@ interface ServiceBaseInterface extends ResourceServiceBaseInterface {
      */
     public function entityList(string|int $collection, ?IFilter $filter = null, ?ISort $sort = null, ?IRange $range = null, ?array $properties = null): array;
 
+    /**
+     * Lists messages in a collection
+     *
+     * @since 2025.05.01
+     *
+     * @param string|int $collection Collection ID
+     * @param IFilter|null $filter Optional filter criteria
+     * @param ISort|null $sort Optional sort order
+     * @param IRange|null $range Optional pagination
+     * @param array|null $properties Optional message properties to fetch
+     *
+     * @return Generator Yields messages one by one as EntityBaseInterface
+     */
+    public function entityListStream(string|int $collection, ?IFilter $filter = null, ?ISort $sort = null, ?IRange $range = null, ?array $properties = null): Generator;
+
     /**
      * Creates a filter builder for messages
      *