Since version 0.4.0.

To gain a better understanding of the status and activity of the relayer, Hermes features a built-in telemetry service based on the OpenTelemetry observability framework, whose metrics can be exposed over HTTP for integration with the Prometheus monitoring system.

The official Hermes builds for Linux and macOS come with telemetry support since version 0.4.0, and can be downloaded directly from the GitHub Releases page.


The telemetry service is not active by default, and must be enabled in the relayer configuration:

enabled = true
host    = ''
port    = 3001

Please see the relevant section in the Configuration page for details about the configuration options.


The following table describes the metrics currently tracked by the telemetry service:

NameDescriptionOpenTelemetry type
workersNumber of workers per objecti64 UpDownCounter
ibc_client_updatesNumber of client updates performed per clientu64 Counter
ibc_client_misbehavioursNumber of misbehaviours detected per clientu64 Counter
ibc_receive_packetsNumber of receive packets relayed per channelu64 Counter
ibc_acknowledgment_packetsNumber of acknowledgment packets relayed per channelu64 Counter
ibc_timeout_packetsNumber of timeout packets relayed per channelu64 Counter

Integration with Prometheus

With the settings , the telemetry service will be enabled and will serve the metrics using the Prometheus encoder over HTTP at http://localhost:3001/metrics.

After starting Hermes with hermes start, and letting it run for a while to relay packets, open http://localhost:3001/metrics in a browser, you should see Prometheus-encoded metrics.

For example, with 3 channels and after transferring some tokens between the chains:

# HELP ibc_acknowledgment_packets Number of acknowledgment packets relayed per channel
# TYPE ibc_acknowledgment_packets counter
ibc_acknowledgment_packets{src_chain="ibc-0",src_channel="channel-0",src_port="transfer"} 300
ibc_acknowledgment_packets{src_chain="ibc-0",src_channel="channel-1",src_port="transfer"} 100
ibc_acknowledgment_packets{src_chain="ibc-1",src_channel="channel-0",src_port="transfer"} 48
ibc_acknowledgment_packets{src_chain="ibc-1",src_channel="channel-1",src_port="transfer"} 0
# HELP ibc_receive_packets Number of receive packets relayed per channel
# TYPE ibc_receive_packets counter
ibc_receive_packets{src_chain="ibc-0",src_channel="channel-0",src_port="transfer"} 48
ibc_receive_packets{src_chain="ibc-0",src_channel="channel-1",src_port="transfer"} 0
ibc_receive_packets{src_chain="ibc-1",src_channel="channel-0",src_port="transfer"} 300
ibc_receive_packets{src_chain="ibc-1",src_channel="channel-1",src_port="transfer"} 100
# HELP ibc_timeout_packets Number of timeout packets relayed per channel
# TYPE ibc_timeout_packets counter
ibc_timeout_packets{src_chain="ibc-0",src_channel="channel-0",src_port="transfer"} 1
ibc_timeout_packets{src_chain="ibc-0",src_channel="channel-1",src_port="transfer"} 0
ibc_timeout_packets{src_chain="ibc-1",src_channel="channel-0",src_port="transfer"} 0
ibc_timeout_packets{src_chain="ibc-1",src_channel="channel-1",src_port="transfer"} 0
# HELP workers Number of workers per object
# TYPE workers gauge
workers{type="client"} 6
workers{type="packet"} 4

Visualization with Grafana

Here's how these metrics look like in Grafana with a Prometheus data source:

Hermes metrics in Grafana