Flipt exposes Prometheus metrics at the /metrics HTTP endpoint. To see which metrics are currently supported, point your browser to FLIPT_HOST/metrics (ex: localhost:8080/metrics).

You should see a bunch of metrics being recorded such as:

flipt_cache_hit_total{cache="memory",type="flag"} 1
flipt_cache_miss_total{cache="memory",type="flag"} 1
go_gc_duration_seconds{quantile="0"} 8.641e-06
go_gc_duration_seconds{quantile="0.25"} 2.499e-05
go_gc_duration_seconds{quantile="0.5"} 3.5359e-05
go_gc_duration_seconds{quantile="0.75"} 6.6594e-05
go_gc_duration_seconds{quantile="1"} 0.00026651 go_gc_duration_seconds_sum
0.000402094 go_gc_duration_seconds_count 5

There is an example provided in the GitHub repository showing how to set up Flipt with Prometheus.


Grafana Dashboard

We have created a set of Grafana dashboards that you can use to visualize the metrics collected by Flipt, including both server health and flag evaluation metrics.

You can find the dashboards in our grafana-dashboards repository.


Flipt supports distributed tracing via the OpenTelemetry project.

Currently, we support the following tracing backends:

Enable tracing via the values described in the Tracing configuration and point Flipt to your configured collector to record spans.

There are examples provided in the main GitHub repository showing how to set up Flipt with each of the supported tracing backends.

Audit Events

Starting from v1.21.0, Flipt supports sending audit events to configured sinks. Audit events have the following structure:

  "version": "0.1",
  "type": "flag",
  "action": "created",
  "metadata": {
    "actor": {
      "authentication": "none",
      "ip": ""
  "payload": {
    "description": "flipt flag",
    "enabled": true,
    "key": "flipt",
    "name": "flipt",
    "namespace_key": "default"
  "timestamp": "1970-01-01T00:00:00Z"
  • version : the version of the audit event structure. We do not expect too many changes to the structure of the audit event
  • type : the type of the entity being acted upon (flag, variant, constraint, etc.)
  • action : the action taken upon the entity (created, deleted, updated, etc.)
  • metadata : extra information related to the audit event as a whole. The actor field will always be present containing some identity information of the source which initiated the audit event
  • payload : the actual payload used to interact with the Flipt server for certain auditable events
  • timestamp: the time the event was created

Currently, we support the following sinks for audit events:

  • Log File: the audit events are JSON encoded and new-line delimited. Configuration found here

You can find examples in the main GitHub repository on how to enable audit events, and how to tune configuration for it.