diff --git a/rpcs3/Emu/NP/ip_address.cpp b/rpcs3/Emu/NP/ip_address.cpp
index 7d9d972d7c..fe0124c74d 100644
--- a/rpcs3/Emu/NP/ip_address.cpp
+++ b/rpcs3/Emu/NP/ip_address.cpp
@@ -66,7 +66,7 @@ namespace np
 		return sockaddr_ipv6;
 	}
 
-	u32 register_ip(const std::string& ip_bytes)
+	u32 register_ip(std::string_view ip_bytes)
 	{
 		if (ip_bytes.size() == 4)
 		{
diff --git a/rpcs3/Emu/NP/ip_address.h b/rpcs3/Emu/NP/ip_address.h
index f019e299cb..39205a007d 100644
--- a/rpcs3/Emu/NP/ip_address.h
+++ b/rpcs3/Emu/NP/ip_address.h
@@ -66,7 +66,7 @@ namespace np
 		std::vector<std::array<u8, 16>> ipv4_to_ipv6;
 	};
 
-	u32 register_ip(const std::string& ip_bytes);
+	u32 register_ip(std::string_view ip_bytes);
 
 	enum class IPV6_SUPPORT : u8
 	{
diff --git a/rpcs3/Emu/NP/np_handler.cpp b/rpcs3/Emu/NP/np_handler.cpp
index 0d628e299e..6b4ada8e84 100644
--- a/rpcs3/Emu/NP/np_handler.cpp
+++ b/rpcs3/Emu/NP/np_handler.cpp
@@ -1303,7 +1303,7 @@ namespace np
 		}
 	}
 
-	bool np_handler::error_and_disconnect(const std::string& error_msg)
+	bool np_handler::error_and_disconnect(std::string_view error_msg)
 	{
 		rpcn_log.error("%s", error_msg);
 		rpcn.reset();
diff --git a/rpcs3/Emu/NP/np_handler.h b/rpcs3/Emu/NP/np_handler.h
index 575fe68941..940ad6eac3 100644
--- a/rpcs3/Emu/NP/np_handler.h
+++ b/rpcs3/Emu/NP/np_handler.h
@@ -267,7 +267,7 @@ namespace np
 		error_code abort_request(u32 req_id);
 
 		// For signaling
-		void req_sign_infos(const std::string& npid, u32 conn_id);
+		void req_sign_infos(std::string_view npid, u32 conn_id);
 
 		// For UPNP
 		void upnp_add_port_mapping(u16 internal_port, std::string_view protocol);
@@ -297,7 +297,7 @@ namespace np
 		// Various generic helpers
 		bool discover_ip_address();
 		bool discover_ether_address();
-		bool error_and_disconnect(const std::string& error_msg);
+		bool error_and_disconnect(std::string_view error_msg);
 
 		// Notification handlers
 		void notif_user_joined_room(vec_stream& noti);
diff --git a/rpcs3/Emu/NP/np_requests.cpp b/rpcs3/Emu/NP/np_requests.cpp
index d9dd6dc337..fb1fb0cfe8 100644
--- a/rpcs3/Emu/NP/np_requests.cpp
+++ b/rpcs3/Emu/NP/np_requests.cpp
@@ -814,7 +814,7 @@ namespace np
 		cb_info_opt->queue_callback(req_id, 0, error_code, 0);
 	}
 
-	void np_handler::req_sign_infos(const std::string& npid, u32 conn_id)
+	void np_handler::req_sign_infos(std::string_view npid, u32 conn_id)
 	{
 		const u32 req_id = get_req_id(REQUEST_ID_HIGH::MISC);
 		{
diff --git a/rpcs3/Emu/NP/rpcn_client.cpp b/rpcs3/Emu/NP/rpcn_client.cpp
index 96ab505abf..da590278f5 100644
--- a/rpcs3/Emu/NP/rpcn_client.cpp
+++ b/rpcs3/Emu/NP/rpcn_client.cpp
@@ -967,7 +967,7 @@ namespace rpcn
 		server_info_received = false;
 	}
 
-	bool rpcn_client::connect(const std::string& host)
+	bool rpcn_client::connect(std::string_view host)
 	{
 		rpcn_log.warning("connect: Attempting to connect");
 
@@ -1172,7 +1172,7 @@ namespace rpcn
 		return true;
 	}
 
-	bool rpcn_client::login(const std::string& npid, const std::string& password, const std::string& token)
+	bool rpcn_client::login(std::string_view npid, std::string_view password, std::string_view token)
 	{
 		if (npid.empty())
 		{
@@ -1338,7 +1338,7 @@ namespace rpcn
 		return error;
 	}
 
-	ErrorType rpcn_client::resend_token(const std::string& npid, const std::string& password)
+	ErrorType rpcn_client::resend_token(std::string_view npid, std::string_view password)
 	{
 		if (authentified)
 		{
@@ -1469,7 +1469,7 @@ namespace rpcn
 		return error;
 	}
 
-	std::optional<ErrorType> rpcn_client::add_friend(const std::string& friend_username)
+	std::optional<ErrorType> rpcn_client::add_friend(std::string_view friend_username)
 	{
 		std::vector<u8> data;
 		std::copy(friend_username.begin(), friend_username.end(), std::back_inserter(data));
@@ -1494,7 +1494,7 @@ namespace rpcn
 		return error;
 	}
 
-	bool rpcn_client::remove_friend(const std::string& friend_username)
+	bool rpcn_client::remove_friend(std::string_view friend_username)
 	{
 		std::vector<u8> data;
 		std::copy(friend_username.begin(), friend_username.end(), std::back_inserter(data));
@@ -2159,7 +2159,7 @@ namespace rpcn
 		return forge_request_with_com_id(serialized, communication_id, CommandType::SendRoomMessage, req_id);
 	}
 
-	bool rpcn_client::req_sign_infos(u32 req_id, const std::string& npid)
+	bool rpcn_client::req_sign_infos(u32 req_id, std::string_view npid)
 	{
 		std::vector<u8> data;
 		std::copy(npid.begin(), npid.end(), std::back_inserter(data));
@@ -2168,7 +2168,7 @@ namespace rpcn
 		return forge_send(CommandType::RequestSignalingInfos, req_id, data);
 	}
 
-	bool rpcn_client::req_ticket(u32 req_id, const std::string& service_id, const std::vector<u8>& cookie)
+	bool rpcn_client::req_ticket(u32 req_id, std::string_view service_id, const std::vector<u8>& cookie)
 	{
 		std::vector<u8> data;
 		std::copy(service_id.begin(), service_id.end(), std::back_inserter(data));
@@ -2859,7 +2859,7 @@ namespace rpcn
 		memcpy(data.data(), com_id_str.data(), COMMUNICATION_ID_SIZE);
 	}
 
-	bool rpcn_client::forge_request_with_com_id(const std::string& serialized_data, const SceNpCommunicationId& com_id, CommandType command, u64 packet_id)
+	bool rpcn_client::forge_request_with_com_id(std::string_view serialized_data, const SceNpCommunicationId& com_id, CommandType command, u64 packet_id)
 	{
 		const usz bufsize = serialized_data.size();
 		std::vector<u8> data(COMMUNICATION_ID_SIZE + sizeof(u32) + bufsize);
@@ -2872,7 +2872,7 @@ namespace rpcn
 		return forge_send(command, packet_id, data);
 	}
 
-	bool rpcn_client::forge_request_with_data(const std::string& serialized_data, CommandType command, u64 packet_id)
+	bool rpcn_client::forge_request_with_data(std::string_view serialized_data, CommandType command, u64 packet_id)
 	{
 		const usz bufsize = serialized_data.size();
 		std::vector<u8> data(sizeof(u32) + bufsize);
@@ -2897,14 +2897,14 @@ namespace rpcn
 		return packet;
 	}
 
-	bool rpcn_client::error_and_disconnect(const std::string& error_msg)
+	bool rpcn_client::error_and_disconnect(std::string_view error_msg)
 	{
 		connected = false;
 		rpcn_log.error("%s", error_msg);
 		return false;
 	}
 
-	bool rpcn_client::error_and_disconnect_notice(const std::string& error_msg)
+	bool rpcn_client::error_and_disconnect_notice(std::string_view error_msg)
 	{
 		connected = false;
 		rpcn_log.notice("%s", error_msg);
diff --git a/rpcs3/Emu/NP/rpcn_client.h b/rpcs3/Emu/NP/rpcn_client.h
index daa60d90e7..e37b1bb2e0 100644
--- a/rpcs3/Emu/NP/rpcn_client.h
+++ b/rpcs3/Emu/NP/rpcn_client.h
@@ -166,7 +166,7 @@ public:
 			vec.push_back(*(reinterpret_cast<u8*>(&value) + index));
 		}
 	}
-	void insert_string(const std::string& str) const
+	void insert_string(std::string_view str) const
 	{
 		std::copy(str.begin(), str.end(), std::back_inserter(vec));
 		vec.push_back(0);
@@ -277,8 +277,8 @@ namespace rpcn
 		bool send_packet(const std::vector<u8>& packet);
 
 	private:
-		bool connect(const std::string& host);
-		bool login(const std::string& npid, const std::string& password, const std::string& token);
+		bool connect(std::string_view host);
+		bool login(std::string_view npid, std::string_view password, std::string_view token);
 		void disconnect();
 
 	public:
@@ -297,12 +297,12 @@ namespace rpcn
 		void remove_friend_cb(friend_cb_func, void* cb_param);
 
 		ErrorType create_user(std::string_view npid, std::string_view password, std::string_view online_name, std::string_view avatar_url, std::string_view email);
-		ErrorType resend_token(const std::string& npid, const std::string& password);
+		ErrorType resend_token(std::string_view npid, std::string_view password);
 		ErrorType send_reset_token(std::string_view npid, std::string_view email);
 		ErrorType reset_password(std::string_view npid, std::string_view token, std::string_view password);
 		ErrorType delete_account();
-		std::optional<ErrorType> add_friend(const std::string& friend_username);
-		bool remove_friend(const std::string& friend_username);
+		std::optional<ErrorType> add_friend(std::string_view friend_username);
+		bool remove_friend(std::string_view friend_username);
 
 		u32 get_num_friends() const;
 		u32 get_num_blocks() const;
@@ -346,8 +346,8 @@ namespace rpcn
 		bool set_userinfo(u32 req_id, const SceNpCommunicationId& communication_id, const SceNpMatching2SetUserInfoRequest* req);
 		bool ping_room_owner(u32 req_id, const SceNpCommunicationId& communication_id, u64 room_id);
 		bool send_room_message(u32 req_id, const SceNpCommunicationId& communication_id, const SceNpMatching2SendRoomMessageRequest* req);
-		bool req_sign_infos(u32 req_id, const std::string& npid);
-		bool req_ticket(u32 req_id, const std::string& service_id, const std::vector<u8>& cookie);
+		bool req_sign_infos(u32 req_id, std::string_view npid);
+		bool req_ticket(u32 req_id, std::string_view service_id, const std::vector<u8>& cookie);
 		bool send_message(const message_data& msg_data, const std::set<std::string>& npids);
 		bool get_board_infos(u32 req_id, const SceNpCommunicationId& communication_id, SceNpScoreBoardId board_id);
 		bool record_score(u32 req_id, const SceNpCommunicationId& communication_id, SceNpScoreBoardId board_id, SceNpScorePcId char_id, SceNpScoreValue score, const std::optional<std::string> comment, const std::optional<std::vector<u8>> score_data);
@@ -396,12 +396,12 @@ namespace rpcn
 
 		std::vector<u8> forge_request(rpcn::CommandType command, u64 packet_id, const std::vector<u8>& data) const;
 		bool forge_send(rpcn::CommandType command, u64 packet_id, const std::vector<u8>& data);
-		bool forge_request_with_com_id(const std::string& serialized_data, const SceNpCommunicationId& com_id, CommandType command, u64 packet_id);
-		bool forge_request_with_data(const std::string& serialized_data, CommandType command, u64 packet_id);
+		bool forge_request_with_com_id(std::string_view serialized_data, const SceNpCommunicationId& com_id, CommandType command, u64 packet_id);
+		bool forge_request_with_data(std::string_view serialized_data, CommandType command, u64 packet_id);
 		bool forge_send_reply(rpcn::CommandType command, u64 packet_id, const std::vector<u8>& data, std::vector<u8>& reply_data);
 
-		bool error_and_disconnect(const std::string& error_mgs);
-		bool error_and_disconnect_notice(const std::string& error_msg);
+		bool error_and_disconnect(std::string_view error_mgs);
+		bool error_and_disconnect_notice(std::string_view error_msg);
 
 		std::string get_wolfssl_error(WOLFSSL* wssl, int error) const;
 
diff --git a/rpcs3/Emu/NP/upnp_handler.cpp b/rpcs3/Emu/NP/upnp_handler.cpp
index c19e30d441..4ebd9084d1 100644
--- a/rpcs3/Emu/NP/upnp_handler.cpp
+++ b/rpcs3/Emu/NP/upnp_handler.cpp
@@ -119,13 +119,14 @@ void upnp_handler::add_port_redir(const std::string& addr, u16 internal_port, st
 	if (!m_active)
 		return;
 
+	const std::string protocol_str(protocol);
+
 	std::lock_guard lock(m_mutex);
 
-	if (m_bindings[std::string(protocol)].contains(internal_port))
+	if (m_bindings[protocol_str].contains(internal_port))
 		return;
 
 	const std::string internal_port_str = fmt::format("%d", internal_port);
-	const std::string protocol_str(protocol);
 	const u32 max_port = std::min(static_cast<u32>(internal_port) + 100, 0xFFFFu);
 	int res = 0;
 
diff --git a/rpcs3/rpcs3qt/rpcn_settings_dialog.cpp b/rpcs3/rpcs3qt/rpcn_settings_dialog.cpp
index cab71be3bc..f927291178 100644
--- a/rpcs3/rpcs3qt/rpcn_settings_dialog.cpp
+++ b/rpcs3/rpcs3qt/rpcn_settings_dialog.cpp
@@ -1353,7 +1353,7 @@ rpcn_friends_dialog::~rpcn_friends_dialog()
 	}
 }
 
-bool rpcn_friends_dialog::add_friend_with_error_dialog(const std::string& friend_username)
+bool rpcn_friends_dialog::add_friend_with_error_dialog(std::string_view friend_username)
 {
 	QString err_msg;
 	const auto opt_error = m_rpcn->add_friend(friend_username);
diff --git a/rpcs3/rpcs3qt/rpcn_settings_dialog.h b/rpcs3/rpcs3qt/rpcn_settings_dialog.h
index c28828e410..a4fd8ec5e0 100644
--- a/rpcs3/rpcs3qt/rpcn_settings_dialog.h
+++ b/rpcs3/rpcs3qt/rpcn_settings_dialog.h
@@ -121,7 +121,7 @@ public:
 private:
 	void add_update_list(QListWidget* list, const QString& name, const QIcon& icon, const QVariant& data);
 	void remove_list(QListWidget* list, const QString& name);
-	bool add_friend_with_error_dialog(const std::string& friend_username);
+	bool add_friend_with_error_dialog(std::string_view friend_username);
 
 private Q_SLOTS:
 	void add_update_friend(const QString& name, bool status);