--- title: Agent admin API slug: feature-experimentation/docs/admin-api docTags: createdAt: 2026-08-05T20:39:52.000Z --- By default, the Agent admin listener is configured on port 8088. ## Info The `/info` endpoint provides basic information about the Optimizely Agent instance. Example request ```shell curl localhost:8088/info ``` Example response ```json { "version": "v0.10.0", "author": "Optimizely Inc.", "app_name": "optimizely" } ``` ## Health check The `/health` endpoint is used to determine service availability. Example request ```shell curl localhost:8088/health ``` Example response ```json { "status": "ok" } ``` Optimizely Agent will return an `HTTP 200 - OK` response if and only if all configured listeners are open and all external dependent services can be reached. A non-healthy service will return an `HTTP 503 - Unavailable` response with a descriptive message to help diagnose the issue. This endpoint can be used when placing Optimizely Agent behind a load balancer to indicate whether a particular instance can receive inbound requests. ## Metrics The `/metrics` endpoint exposes telemetry data of the running Optimizely Agent. Optimizely Agent currently exposes two metrics data types ([expvar](https://pkg.go.dev/expvar) and [prometheus](https://pkg.go.dev/github.com/prometheus/client_golang/prometheus)) based on the user's input. Expvar metrics are used by default. To configure the metrics, update the `config.yaml` file or set the value of the `OPTIMIZELY_ADMIN_METRICSTYPE` environment variable. Supported values - `expvar` (default) - `prometheus` ```yaml admin: ## http listener port port: "8088" ## metrics package to use ## supported packages are expvar and prometheus ## default is expvar metricsType: "" ## metricsType: "prometheus" ## for prometheus metrics ``` ### Expvar metrics The core Optimizely Agent runtime metrics are exposed through the [Go expvar package](https://pkg.go.dev/expvar), which provides a standardized interface to public variables. Documentation for the various statistics can be found as part of the [mstats package](https://go.dev/src/runtime/mstats.go). Example request ```shell curl localhost:8088/metrics ``` Example response ```json { "cmdline": [ "bin/optimizely" ], "memstats": { "Alloc": 924136, "TotalAlloc": 924136, "Sys": 71893240, "Lookups": 0, "Mallocs": 4726, "HeapAlloc": 924136, ... "Frees": 172 }, ... } ``` Custom metrics are also provided for the individual service endpoints and follow the pattern of the following: ```shell "timers..counts": 0, "timers..responseTime": 0, "timers..responseTimeHist.p50": 0, "timers..responseTimeHist.p90": 0, "timers..responseTimeHist.p95": 0, "timers..responseTimeHist.p99": 0, ``` ### Prometheus metrics Optimizely Agent supports [Prometheus](https://pkg.go.dev/github.com/prometheus/client_golang/prometheus) metrics. Prometheus is an open-source toolkit for monitoring and alerting. You can use it to collect and visualize metrics in a time-series database. To access the Prometheus metrics, you can use the `/metrics` endpoint with a Prometheus server. The metrics are exposed in a format that Prometheus can scrape and aggregate. Example Request ```shell curl localhost:8088/metrics ``` This will return a plain text response in the [Prometheus exposition format](https://prometheus.io/docs/instrumenting/exposition_formats/#exposition-formats), including the metrics Prometheus is currently tracking. :::hint{type="info"} **Note** You must configure your Prometheus server to scrape metrics from this endpoint. ::: For information on how to use Prometheus for monitoring, see the [official Prometheus documentation](https://prometheus.io/docs/introduction/overview/). Example Response ```javascript ... # HELP promhttp_metric_handler_requests_total Total number of scrapes by HTTP status code. # TYPE promhttp_metric_handler_requests_total counter promhttp_metric_handler_requests_total{code="200"} 1 promhttp_metric_handler_requests_total{code="500"} 0 promhttp_metric_handler_requests_total{code="503"} 0 # HELP timer_decide_hits # TYPE timer_decide_hits counter timer_decide_hits 1 # HELP timer_decide_response_time # TYPE timer_decide_response_time counter timer_decide_response_time 658.109 # HELP timer_decide_response_time_hist # TYPE timer_decide_response_time_hist histogram timer_decide_response_time_hist_bucket{le="0.005"} 0 timer_decide_response_time_hist_bucket{le="0.01"} 0 timer_decide_response_time_hist_bucket{le="0.025"} 0 timer_decide_response_time_hist_bucket{le="0.05"} 0 timer_decide_response_time_hist_bucket{le="0.1"} 0 timer_decide_response_time_hist_bucket{le="0.25"} 0 timer_decide_response_time_hist_bucket{le="0.5"} 0 timer_decide_response_time_hist_bucket{le="1"} 0 timer_decide_response_time_hist_bucket{le="2.5"} 0 timer_decide_response_time_hist_bucket{le="5"} 0 timer_decide_response_time_hist_bucket{le="10"} 0 timer_decide_response_time_hist_bucket{le="+Inf"} 1 timer_decide_response_time_hist_sum 658.109 timer_decide_response_time_hist_count 1 # HELP timer_track_event_hits # TYPE timer_track_event_hits counter timer_track_event_hits 1 # HELP timer_track_event_response_time # TYPE timer_track_event_response_time counter timer_track_event_response_time 0.356334 # HELP timer_track_event_response_time_hist # TYPE timer_track_event_response_time_hist histogram timer_track_event_response_time_hist_bucket{le="0.005"} 0 timer_track_event_response_time_hist_bucket{le="0.01"} 0 timer_track_event_response_time_hist_bucket{le="0.025"} 0 timer_track_event_response_time_hist_bucket{le="0.05"} 0 timer_track_event_response_time_hist_bucket{le="0.1"} 0 timer_track_event_response_time_hist_bucket{le="0.25"} 0 timer_track_event_response_time_hist_bucket{le="0.5"} 1 timer_track_event_response_time_hist_bucket{le="1"} 1 timer_track_event_response_time_hist_bucket{le="2.5"} 1 timer_track_event_response_time_hist_bucket{le="5"} 1 timer_track_event_response_time_hist_bucket{le="10"} 1 timer_track_event_response_time_hist_bucket{le="+Inf"} 1 timer_track_event_response_time_hist_sum 0.356334 timer_track_event_response_time_hist_count 1 ... ```