diff --git a/backend.php b/backend.php
index 5b1587741..9fa30db38 100644
--- a/backend.php
+++ b/backend.php
@@ -145,8 +145,8 @@
 				$b_scope->close();
 
 				if ($before) {
+					$m_scope = Tracer::start("method/$method");
 					if ($method && method_exists($handler, $method)) {
-						$m_scope = Tracer::start("method/$method");
 						$reflection = new ReflectionMethod($handler, $method);
 
 						if ($reflection->getNumberOfRequiredParameters() == 0) {
@@ -154,17 +154,21 @@
 						} else {
 							user_error("Refusing to invoke method $method of handler $op which has required parameters.", E_USER_WARNING);
 							header("Content-Type: text/json");
+
+							$m_scope->getSpan()->setTag('error', Errors::E_UNAUTHORIZED);
 							print Errors::to_json(Errors::E_UNAUTHORIZED);
 						}
-						$m_scope->close();
 					} else {
 						if (method_exists($handler, "catchall")) {
 							$handler->catchall($method);
 						} else {
 							header("Content-Type: text/json");
+
+							$m_scope->getSpan()->setTag('error', Errors::E_UNKNOWN_METHOD);
 							print Errors::to_json(Errors::E_UNKNOWN_METHOD, ["info" => get_class($handler) . "->$method"]);
 						}
 					}
+					$m_scope->close();
 
 					$a_scope = Tracer::start("after/$method");
 					$handler->after();
@@ -176,6 +180,7 @@
 					header("Content-Type: text/json");
 					print Errors::to_json(Errors::E_UNAUTHORIZED);
 
+					$scope->getSpan()->setTag('error', Errors::E_UNAUTHORIZED);
 					$scope->close();
 					return;
 				}
@@ -184,6 +189,7 @@
 				header("Content-Type: text/json");
 				print Errors::to_json(Errors::E_UNAUTHORIZED);
 
+				$scope->getSpan()->setTag('error', Errors::E_UNAUTHORIZED);
 				$scope->close();
 				return;
 			}
@@ -193,4 +199,5 @@
 	header("Content-Type: text/json");
 	print Errors::to_json(Errors::E_UNKNOWN_METHOD, [ "info" => (isset($handler) ? get_class($handler) : "UNKNOWN:".$op) . "->$method"]);
 
+	$scope->getSpan()->setTag('error', Errors::E_UNKNOWN_METHOD);
 	$scope->close();
diff --git a/classes/config.php b/classes/config.php
index dee6caa38..a9c75ae7b 100644
--- a/classes/config.php
+++ b/classes/config.php
@@ -192,6 +192,9 @@ class Config {
 	/** delay updates for this feed if received HTTP 429 (Too Many Requests) for this amount of seconds (base value, actual delay is base...base*2) */
 	const HTTP_429_THROTTLE_INTERVAL = "HTTP_429_THROTTLE_INTERVAL";
 
+	/** host running Jaeger collector to receive traces (disabled if empty) */
+	const JAEGER_REPORTING_HOST = "JAEGER_REPORTING_HOST";
+
 	/** default values for all global configuration options */
 	private const _DEFAULTS = [
 		Config::DB_TYPE => [ "pgsql", 									Config::T_STRING ],
@@ -249,6 +252,7 @@ class Config {
 		Config::HTTP_USER_AGENT => [ 'Tiny Tiny RSS/%s (https://tt-rss.org/)',
 																					Config::T_STRING ],
 		Config::HTTP_429_THROTTLE_INTERVAL => [ 3600,				Config::T_INT ],
+		Config::JAEGER_REPORTING_HOST => [ "",							Config::T_STRING ],
 	];
 
 	/** @var Config|null */
diff --git a/classes/feeds.php b/classes/feeds.php
index 1ce19b098..9707d5e45 100755
--- a/classes/feeds.php
+++ b/classes/feeds.php
@@ -987,7 +987,7 @@ class Feeds extends Handler_Protected {
 	 * @throws PDOException
 	 */
 	static function _get_counters($feed, bool $is_cat = false, bool $unread_only = false, ?int $owner_uid = null): int {
-		$scope = Tracer::start(__FUNCTION__, ['tags' => ['args' => json_encode(func_get_args())]]);
+		$scope = Tracer::start(__FUNCTION__, [], func_get_args());
 
 		$n_feed = (int) $feed;
 		$need_entries = false;
diff --git a/classes/pref/feeds.php b/classes/pref/feeds.php
index 00d26d4f6..42adf23ca 100755
--- a/classes/pref/feeds.php
+++ b/classes/pref/feeds.php
@@ -1104,7 +1104,7 @@ class Pref_Feeds extends Handler_Protected {
 	 * @return array<string, mixed>
 	 */
 	private function feedlist_init_feed(int $feed_id, ?string $title = null, bool $unread = false, string $error = '', string $updated = ''): array {
-		$scope = Tracer::start(__FUNCTION__, ['tags' => ['args' => json_encode(func_get_args())]]);
+		$scope = Tracer::start(__FUNCTION__, [], func_get_args());
 
 		if (!$title)
 			$title = Feeds::_get_title($feed_id, false);
diff --git a/classes/tracer.php b/classes/tracer.php
index fde99927d..1326f4344 100644
--- a/classes/tracer.php
+++ b/classes/tracer.php
@@ -3,39 +3,59 @@ use OpenTracing\GlobalTracer;
 use OpenTracing\Scope;
 
 class Tracer {
+	/** @var Tracer $instance */
 	private static $instance;
 
 	public function __construct() {
-		$config = new \Jaeger\Config(
-			[
-				'sampler' => [
-					'type' => \Jaeger\SAMPLER_TYPE_CONST,
-					'param' => true,
-				],
-				'logging' => true,
-				"local_agent" => [
-					"reporting_host" => "172.17.172.39",
-					"reporting_port" => 6832
-				],
-				'dispatch_mode' => \Jaeger\Config::JAEGER_OVER_BINARY_UDP,
-			],
-			'tt-rss'
-		);
+		$jaeger_host = Config::get(Config::JAEGER_REPORTING_HOST);
 
-		$config->initializeTracer();
+		if ($jaeger_host) {
+			$config = new \Jaeger\Config(
+				[
+					'sampler' => [
+						'type' => \Jaeger\SAMPLER_TYPE_CONST,
+						'param' => true,
+					],
+					'logging' => true,
+					"local_agent" => [
+						"reporting_host" => $jaeger_host,
+						"reporting_port" => 6832
+					],
+					'dispatch_mode' => \Jaeger\Config::JAEGER_OVER_BINARY_UDP,
+				],
+				'tt-rss'
+			);
 
-		register_shutdown_function(function() {
-			$tracer = GlobalTracer::get();
-			$tracer->flush();
-		});
+			$config->initializeTracer();
+
+			register_shutdown_function(function() {
+				$tracer = GlobalTracer::get();
+				$tracer->flush();
+			});
+		}
 	}
 
-	private function _start(string $name, array $options = []) {
+	/**
+	 * @param string $name
+	 * @param array<mixed> $options
+	 * @param array<string> $args
+	 * @return Scope
+	 */
+	private function _start(string $name, array $options = [], array $args = []): Scope {
 		$tracer = GlobalTracer::get();
+
+		$options['tags']['args'] = json_encode($args);
+
 		return $tracer->startActiveSpan($name, $options);
 	}
 
-	public static function start(string $name, array $options = []) : Scope {
+	/**
+	 * @param string $name
+	 * @param array<string> $options
+	 * @param array<string> $args
+	 * @return Scope
+	 */
+	public static function start(string $name, array $options = [], array $args = []) : Scope {
 		return self::get_instance()->_start($name, $options);
 	}