# Metrics > The Things Stack exports Prometheus telemetry on the /metrics endpoint. This reference gives an overview of the most important metrics. Source: https://www.thethingsindustries.com/docs/concepts/advanced/metrics/ The Things Stack exports [Prometheus](https://prometheus.io/) telemetry on the `/metrics` endpoint. This reference gives an overview of the most important metrics. > **Warning:** Metrics are not covered by our compatibility commitment. This means that metrics may be changed or removed in major, minor, or patch releases. This page only lists metrics that are considered relatively stable, but even these metrics may be changed. > **Note:** Metrics are exported and available only when a corresponding action takes place in The Things Stack. For example, to get the connected gateway's metric (`ttn_lw_gs_connected_gateways`), a gateway should be connected to propagate that metric. ## Process and Go Metrics The Things Stack uses the [Prometheus instrumentation library for Go](https://github.com/prometheus/client_golang/) that includes a collector for the state of the process (on Linux) and metrics from the Go runtime. ## gRPC metrics The Things Stack uses the [Prometheus gRPC instrumentation library](https://github.com/grpc-ecosystem/go-grpc-prometheus) that exposes metrics about gRPC method calls. - `grpc_server_conns_opened_total` and `grpc_server_conns_closed_total` can be used to see how many gRPC connections to The Things Stack are opened, and how many are currently open. - `grpc_server_started_total` and `grpc_server_handled_total` can be used to see how many RPCs to The Things Stack are started, active and finished (including response code). - `grpc_server_msg_sent_total` and `grpc_server_msg_received_total` can be used to see how many RPC messages are sent/received by the server. Similar metrics exist for gRPC client connections opened by The Things Stack, and RPCs made by The Things Stack. ## General Metrics - Enterprise `ttn_lw_license_expiry_seconds` can be used to keep track of license expiry - `ttn_lw_log_messages_total` can be used to track the log messages written by different log namespaces at different log levels. - Before version 3.13.1 this metric was called `ttn_lw_log_log_messages_total`. - `ttn_lw_events_publishes_total` can be used to track the published events by event type. - `ttn_lw_events_channel_dropped_total` can be used to watch for dropped events, which typically indicates that a consumer (such as a user's web browser) can't keep up. - `ttn_lw_workerpool_workers_started` and `ttn_lw_workerpool_workers_stopped` indicate the total number of workers started, and stopped, in the worker pools. - `ttn_lw_workerpool_workers_idle` indicates the number of workers which are idle (not currently processing any work item) in the worker pools. - `ttn_lw_workerpool_work_queue_size` indicates the number of elements found in the queue of the worker pools. - `ttn_lw_workerpool_work_processed` and `ttn_lw_workerpool_work_dropped` indicates the total amount of work processed, or dropped, by the worker pools. For the Gateway Server: - `ttn_lw_gs_connected_gateways` indicates the number of connected gateways. - `ttn_lw_gs_uplink_received_total` indicates the number of uplink messages received from gateways. - `ttn_lw_gs_downlink_sent_total` indicates the number of downlink messages sent to gateways. - `ttn_lw_gs_status_received_total` indicates the number of status messages received from gateways. - `ttn_lw_gs_uplink_forwarded_total` indicates the number of uplink messages forwarded to the Network Server or Packet Broker. - `ttn_lw_gs_uplink_dropped_total` indicates the number of uplink messages that are dropped for various reasons. - `ttn_lw_gs_uplink_failed_total` indicates the number of uplink messages for which the processing has failed for various reasons. - `ttn_lw_gs_downlink_tx_success_total` and `ttn_lw_gs_downlink_tx_failed_total` indicates the number of successful transmissions, and failed transmissions for various reasons, reported by the gateways. For the Packet Broker Agent: - `ttn_lw_pba_uplink_received_total` indicates the number of uplink messages received from Packet Broker (as a home network). - `ttn_lw_pba_downlink_forwarded_total` indicates the number of downlink messages sent to Packet Broker (as a home network). - `ttn_lw_pba_downlink_received_total` indicates the number of downlink messages received from Packet Broker (as a forwarder). - `ttn_lw_pba_uplink_forwarded_total` indicates the number of uplink messages sent to Packet Broker (as a forwarder). For the Network Server: - `ttn_lw_ns_uplink_received_total` indicates the number of uplink messages received from the Gateway Server or Packet Broker. - `ttn_lw_ns_uplink_duplicates_total` indicates the number of duplicate uplinks that are merged into a single uplink. - `ttn_lw_ns_uplink_processed_total` indicates the number of processed uplinks, meaning uplinks that are matched to a device. - `ttn_lw_ns_uplink_forwarded_total` indicates the number of uplinks forwarded to an Application Server. - `ttn_lw_ns_uplink_dropped_total` indicates the number of uplinks that are dropped for various reasons. - `ttn_lw_ns_downlink_attempted_total` indicates the number of downlink attempts. - `ttn_lw_ns_downlink_forwarded_total` indicates the number of downlinks forwarded to the Gateway Server. - `ttn_lw_ns_uplink_gateways` is a histogram that indicates the number of gateways that received a given uplink. For the Application Server: - `ttn_lw_as_subscriptions_started_total` and `ttn_lw_as_subscriptions_stopped_total` indicate the number of started/stopped uplink subscriptions from integrations and external applications. - `ttn_lw_as_pubsub_integrations_started_total` and `ttn_lw_as_pubsub_integrations_stopped_total` indicate the number of started/stopped pub/sub integrations. - `ttn_lw_as_uplink_received_total` indicates the number of uplink messages received from the Network Server. - `ttn_lw_as_uplink_forwarded_total` indicates the number of uplink messages forwarded to integrations and external applications. - `ttn_lw_as_uplink_dropped_total` indicates the number of uplink messages dropped for various reasons. - `ttn_lw_as_downlink_received_total` indicates the number of downlink messages received from integrations and external applications. - `ttn_lw_as_downlink_forwarded_total` indicates the number of downlink messages forwarded to the Network Server. - `ttn_lw_as_downlink_dropped_total` indicates the number of downlink messages dropped for various reasons. - `ttn_lw_as_subscription_sets_started_total` and `ttn_lw_as_subscription_sets_stopped_total` indicates the total number of subscriptions sets started and stopped. - `ttn_lw_as_packages_processed_total` and `ttn_lw_as_packages_failed_total` indicates the total number of uplink messages processed, or which have failed processing for various reasons, by application packages. - `ttn_lw_as_packages_storage_upstream_messages_stored` and `ttn_lw_as_packages_storage_upstream_messages_dropped` indicates the total number of uplink messages stored, or dropped for various reasons, by the Storage Integration. - `ttn_lw_as_webhook_sent_total` and `ttn_lw_as_webhook_failed_total` indicates the total number of webhook messages sent, or failed for various reasons. - `ttn_lw_javascript_run_latency_seconds` is a histogram that indicates the duration of executing JavaScript payload formatters. For the Join Server: - `ttn_lw_js_join_accepted_total` and `ttn_lw_js_join_rejected_total` indicate the number of accepted and rejected join requests.