diff --git a/src/Diagnostics/PanelLogger.php b/src/Diagnostics/PanelLogger.php
index 06135480..f51b2f21 100644
--- a/src/Diagnostics/PanelLogger.php
+++ b/src/Diagnostics/PanelLogger.php
@@ -201,7 +201,7 @@ private function logQuery(
 				'uri' => $request->getUri()->getPath(),
 				'requestBody' =>
 					\Tracy\Dumper::toHtml(
-						\Nette\Utils\Json::decode($contents, \JSON_OBJECT_AS_ARRAY),
+						$this->decodeBody($contents),
 						[
 							\Tracy\Dumper::DEPTH => 30,
 						],
@@ -218,10 +218,9 @@ private function logQuery(
 			if ($contents === '') {
 				$contents = '{}';
 			}
-			$decoded = \Nette\Utils\Json::decode($contents, \JSON_OBJECT_AS_ARRAY);
 			$query['responseBody'] =
 				\Tracy\Dumper::toHtml(
-					$decoded,
+					$this->decodeBody($contents),
 					[
 						\Tracy\Dumper::DEPTH => 30,
 					],
@@ -236,4 +235,36 @@ private function logQuery(
 	}
 
 
+	/**
+	 * Bulk API bodies are NDJSON (one JSON document per line), not a single JSON document.
+	 * Diagnostics must never break the request itself, so anything undecodable is dumped
+	 * as the raw string instead of throwing.
+	 */
+	private function decodeBody(
+		string $contents,
+	): mixed
+	{
+		try {
+			return \Nette\Utils\Json::decode($contents, \JSON_OBJECT_AS_ARRAY);
+		} catch (\Nette\Utils\JsonException) {
+			// Not a single JSON document, try NDJSON below.
+		}
+
+		$documents = [];
+		foreach (\explode("\n", $contents) as $line) {
+			if (\trim($line) === '') {
+				continue;
+			}
+
+			try {
+				$documents[] = \Nette\Utils\Json::decode($line, \JSON_OBJECT_AS_ARRAY);
+			} catch (\Nette\Utils\JsonException) {
+				return $contents;
+			}
+		}
+
+		return $documents;
+	}
+
+
 }
diff --git a/tests/SpameriTests/Elastic/Diagnostics/PanelLoggerTest.phpt b/tests/SpameriTests/Elastic/Diagnostics/PanelLoggerTest.phpt
new file mode 100644
index 00000000..e2b256c3
--- /dev/null
+++ b/tests/SpameriTests/Elastic/Diagnostics/PanelLoggerTest.phpt
@@ -0,0 +1,113 @@
+<?php declare(strict_types = 1);
+
+namespace SpameriTests\Elastic\Diagnostics;
+
+require_once __DIR__ . '/../../../bootstrap-unit.php';
+
+/**
+ * @testCase
+ */
+class PanelLoggerTest extends \Tester\TestCase
+{
+
+	private \Spameri\Elastic\Diagnostics\PanelLogger $panelLogger;
+
+
+	protected function setUp(): void
+	{
+		$this->panelLogger = new \Spameri\Elastic\Diagnostics\PanelLogger(
+			new \Psr\Log\NullLogger(),
+		);
+	}
+
+
+	public function testLogsSingleJsonDocumentRequest(): void
+	{
+		$this->panelLogger->info('Request: POST /index/_search', [
+			'request' => new \GuzzleHttp\Psr7\Request(
+				'POST',
+				'http://localhost:9200/index/_search',
+				[],
+				'{"query": {"match_all": {}}}',
+			),
+		]);
+
+		$queries = $this->panelLogger->getQueries();
+
+		\Tester\Assert::count(1, $queries);
+		\Tester\Assert::same('/index/_search', $queries[0]['uri']);
+		\Tester\Assert::contains('match_all', $queries[0]['requestBody']);
+	}
+
+
+	public function testLogsNdjsonBulkRequestWithoutThrowing(): void
+	{
+		$ndjsonBody = '{"index": {"_index": "index", "_id": "1"}}' . "\n"
+			. '{"name": "First document"}' . "\n"
+			. '{"index": {"_index": "index", "_id": "2"}}' . "\n"
+			. '{"name": "Second document"}' . "\n";
+
+		$this->panelLogger->info('Request: POST /_bulk', [
+			'request' => new \GuzzleHttp\Psr7\Request(
+				'POST',
+				'http://localhost:9200/_bulk',
+				[],
+				$ndjsonBody,
+			),
+		]);
+
+		$queries = $this->panelLogger->getQueries();
+
+		\Tester\Assert::count(1, $queries);
+		\Tester\Assert::same('/_bulk', $queries[0]['uri']);
+		\Tester\Assert::contains('First document', $queries[0]['requestBody']);
+		\Tester\Assert::contains('Second document', $queries[0]['requestBody']);
+	}
+
+
+	public function testLogsUndecodableBodyAsRawString(): void
+	{
+		$this->panelLogger->info('Request: POST /index/_doc', [
+			'request' => new \GuzzleHttp\Psr7\Request(
+				'POST',
+				'http://localhost:9200/index/_doc',
+				[],
+				'not json at all',
+			),
+		]);
+
+		$queries = $this->panelLogger->getQueries();
+
+		\Tester\Assert::count(1, $queries);
+		\Tester\Assert::contains('not json at all', $queries[0]['requestBody']);
+	}
+
+
+	public function testPairsResponseWithRequest(): void
+	{
+		$this->panelLogger->info('Request: POST /index/_search', [
+			'request' => new \GuzzleHttp\Psr7\Request(
+				'POST',
+				'http://localhost:9200/index/_search',
+				[],
+				'{"query": {"match_all": {}}}',
+			),
+		]);
+		$this->panelLogger->info('Response (retry 0): 200', [
+			'response' => new \GuzzleHttp\Psr7\Response(
+				200,
+				[],
+				'{"took": 1, "hits": {"total": {"value": 0}}}',
+			),
+		]);
+
+		$queries = $this->panelLogger->getQueries();
+
+		\Tester\Assert::count(1, $queries);
+		\Tester\Assert::contains('hits', $queries[0]['responseBody']);
+		\Tester\Assert::true(isset($queries[0]['duration']));
+	}
+
+}
+
+(new PanelLoggerTest())->run();