diff --git a/src/onnx/execution/context.cpp b/src/onnx/execution/context.cpp
index 889413f..5996c59 100644
--- a/src/onnx/execution/context.cpp
+++ b/src/onnx/execution/context.cpp
@@ -4,7 +4,7 @@
 
 #include "../../onnxruntime_server.hpp"
 
-Orts::onnx::execution::context::context(Orts::onnx::session *session, const json &json_str)
+Orts::onnx::execution::context::context(std::shared_ptr<Orts::onnx::session> session, const json &json_str)
 	: memory_info(Ort::MemoryInfo::CreateCpu(OrtArenaAllocator, OrtMemTypeDefault)), session(session) {
 	assert(session != nullptr);
 
diff --git a/src/onnx/session_manager.cpp b/src/onnx/session_manager.cpp
index e5042aa..ea829f5 100644
--- a/src/onnx/session_manager.cpp
+++ b/src/onnx/session_manager.cpp
@@ -9,18 +9,15 @@ Orts::onnx::session_manager::session_manager(model_bin_getter_t model_bin_getter
 }
 
 Orts::onnx::session_manager::~session_manager() {
-	for (auto &it : sessions) {
-		delete it.second;
-	}
 }
 
-Orts::onnx::session *
+std::shared_ptr<Orts::onnx::session>
 Orts::onnx::session_manager::get_session(const std::string &model_name, const std::string &model_version) {
 	auto key = session_key(model_name, model_version);
 	return get_session(key);
 }
 
-Orts::onnx::session *Orts::onnx::session_manager::get_session(const Orts::onnx::session_key &key) {
+std::shared_ptr<Orts::onnx::session> Orts::onnx::session_manager::get_session(const Orts::onnx::session_key &key) {
 	std::lock_guard<std::recursive_mutex> lock(mutex);
 	auto it = sessions.find(key);
 	if (it == sessions.end())
@@ -28,7 +25,7 @@ Orts::onnx::session *Orts::onnx::session_manager::get_session(const Orts::onnx::
 	return it->second;
 }
 
-Orts::onnx::session *Orts::onnx::session_manager::create_session(
+std::shared_ptr<Orts::onnx::session> Orts::onnx::session_manager::create_session(
 	const std::string &model_name, const std::string &model_version, const json &option, const char *model_data,
 	size_t model_data_length
 ) {
@@ -49,7 +46,7 @@ Orts::onnx::session *Orts::onnx::session_manager::create_session(
 		if (current_session != nullptr)
 			throw conflict_error("session already exists");
 
-		auto session = new onnx::session(key, model_data, model_data_length, option);
+		auto session = std::make_shared<onnx::session>(key, model_data, model_data_length, option);
 		sessions.emplace(key, session);
 		return session;
 	}
@@ -67,6 +64,5 @@ void Orts::onnx::session_manager::remove_session(const Orts::onnx::session_key &
 	if (it == sessions.end()) {
 		throw not_found_error("session not found");
 	}
-	delete it->second;
 	sessions.erase(it);
 }
diff --git a/src/onnxruntime_server.hpp b/src/onnxruntime_server.hpp
index 9cfe2bf..82ce47e 100644
--- a/src/onnxruntime_server.hpp
+++ b/src/onnxruntime_server.hpp
@@ -123,20 +123,20 @@ namespace onnxruntime_server {
 		class session_manager {
 		  private:
 			std::recursive_mutex mutex;
-			std::map<session_key, session *> sessions;
+			std::map<session_key, std::shared_ptr<session>> sessions;
 			model_bin_getter_t model_bin_getter;
 
 		  public:
 			explicit session_manager(model_bin_getter_t model_bin_getter);
 			~session_manager();
 
-			std::map<session_key, session *> &get_sessions() {
+			std::map<session_key, std::shared_ptr<session>> &get_sessions() {
 				return sessions;
 			}
 
-			session *get_session(const std::string &model_name, const std::string &model_version);
-			session *get_session(const session_key &key);
-			session *create_session(
+			std::shared_ptr<session> get_session(const std::string &model_name, const std::string &model_version);
+			std::shared_ptr<session> get_session(const session_key &key);
+			std::shared_ptr<session> create_session(
 				const std::string &model_name, const std::string &model_version, const json &option,
 				const char *model_data = nullptr, size_t model_data_length = 0
 			);
@@ -161,11 +161,11 @@ namespace onnxruntime_server {
 			class context {
 			  private:
 				Ort::MemoryInfo memory_info;
-				onnxruntime_server::onnx::session *session;
+				std::shared_ptr<onnxruntime_server::onnx::session> session;
 				std::map<std::string, input_value *> inputs;
 
 			  public:
-				context(class session *session, const json &json_str);
+				context(std::shared_ptr<class session> session, const json &json_str);
 				~context();
 
 				void flat_json_values(const json::value_type &data, std::vector<json::value_type> *json_values);
diff --git a/src/task/create_session.cpp b/src/task/create_session.cpp
index 4eba673..10a9df6 100644
--- a/src/task/create_session.cpp
+++ b/src/task/create_session.cpp
@@ -32,7 +32,7 @@ Orts::task::create_session::create_session(
 }
 
 json Orts::task::create_session::run() {
-	Orts::onnx::session *session =
+	std::shared_ptr<Orts::onnx::session> session =
 		onnx_session_manager->create_session(model_name, model_version, option, model_data, model_data_length);
 	if (session == nullptr) {
 		throw not_found_error("session not found");
diff --git a/src/test/unit/unit_test_context.cpp b/src/test/unit/unit_test_context.cpp
index 4122d8b..45728f6 100644
--- a/src/test/unit/unit_test_context.cpp
+++ b/src/test/unit/unit_test_context.cpp
@@ -6,9 +6,9 @@
 
 TEST(test_onnxruntime_server_context, SimpleModelTest) {
 	Orts::onnx::session_key key("sample", "1");
-	Orts::onnx::session session(key, model1_path.string());
+	auto session = std::make_shared<Orts::onnx::session>(key, model1_path.string());
 
-	Orts::onnx::execution::context ctx(&session, R"({"x":[[1]],"y":[[2]],"z":[[3]]})");
+	Orts::onnx::execution::context ctx(session, R"({"x":[[1]],"y":[[2]],"z":[[3]]})");
 
 	TIME_MEASURE_INIT
 	TIME_MEASURE_START
@@ -24,9 +24,9 @@ TEST(test_onnxruntime_server_context, SimpleModelTest) {
 
 TEST(test_onnxruntime_server_context, SimpleModelBatchTest) {
 	Orts::onnx::session_key key("sample", "1");
-	Orts::onnx::session session(key, model1_path.string());
+	auto session = std::make_shared<Orts::onnx::session>(key, model1_path.string());
 
-	Orts::onnx::execution::context ctx(&session, R"({"x":[[1],[2],[3]],"y":[[2],[3],[4]],"z":[[3],[4],[5]]})");
+	Orts::onnx::execution::context ctx(session, R"({"x":[[1],[2],[3]],"y":[[2],[3],[4]],"z":[[3],[4],[5]]})");
 
 	TIME_MEASURE_INIT
 	TIME_MEASURE_START
@@ -42,11 +42,11 @@ TEST(test_onnxruntime_server_context, SimpleModelBatchTest) {
 
 TEST(test_onnxruntime_server_context, BertSquadModelTest) {
 	Orts::onnx::session_key key("sample", "2");
-	Orts::onnx::session session(key, model2_path.string());
+	auto session = std::make_shared<Orts::onnx::session>(key, model2_path.string());
 
-	std::cout << session.to_json().dump(2) << "\n";
+	std::cout << session->to_json().dump(2) << "\n";
 
-	Orts::onnx::execution::context ctx(&session, R"({
+	Orts::onnx::execution::context ctx(session, R"({
 		"input_ids": [
 			[101, 11834, 21600, 2102, 9005, 12098, 8566, 5740, 6853, 1999, 1996, 2806, 1997, 15262, 19699, 14663, 1005, 1055, 3203, 8447, 102, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
 			[101, 3795, 3361, 3422, 16168, 19428, 1997, 1520, 2582, 7860, 1998, 28215, 1521, 3805, 102, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
diff --git a/src/test/unit/unit_test_context_cuda.cpp b/src/test/unit/unit_test_context_cuda.cpp
index 944ef04..077e401 100644
--- a/src/test/unit/unit_test_context_cuda.cpp
+++ b/src/test/unit/unit_test_context_cuda.cpp
@@ -6,11 +6,11 @@
 
 TEST(test_onnxruntime_server_context_cuda, BertSquadModelTest) {
 	Orts::onnx::session_key key("sample", "2");
-	Orts::onnx::session session(key, model2_path.string(), json::parse(R"({"cuda": true})"));
+	auto session = std::make_shared<Orts::onnx::session>(key, model2_path.string(), json::parse(R"({"cuda": true})"));
 
-	std::cout << session.to_json().dump(2) << "\n";
+	std::cout << session->to_json().dump(2) << "\n";
 
-	Orts::onnx::execution::context ctx(&session, R"({
+	Orts::onnx::execution::context ctx(session, R"({
 		"input_ids": [
 			[101, 11834, 21600, 2102, 9005, 12098, 8566, 5740, 6853, 1999, 1996, 2806, 1997, 15262, 19699, 14663, 1005, 1055, 3203, 8447, 102, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
 			[101, 3795, 3361, 3422, 16168, 19428, 1997, 1520, 2582, 7860, 1998, 28215, 1521, 3805, 102, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],