Exposed Metrics

The exporter exposes a standard /metrics HTTP endpoint that Prometheus can scrape.

To prevent Prometheus timeouts and browser race conditions, all metrics are cached. They are updated continuously by a background goroutine, and instantly served upon a scrape request.

All metrics are tagged with the service label configured in config.yaml, enabling seamless multi-tenant dashboarding.

Metric Reference

Metric Name	Type	Labels	Description
synthetic_http_status_code	Gauge	service, endpoint	The HTTP response status code for the API endpoints (e.g., 200, 404). Returns -1 on network failure.
synthetic_ssl_cert_expiry_timestamp_seconds	Gauge	service, endpoint	Unix timestamp (in seconds) of the TLS certificate expiration date. Returns -1 if no certificate is present.
synthetic_ui_step_duration_seconds	Gauge	service, scenario, step, action	The elapsed time in seconds it took to successfully complete a specific UI journey step.
synthetic_ui_journey_success	Gauge	service, scenario	Emits 1 if the entire UI scenario passed successfully, and 0 if any single step failed.
synthetic_ui_journey_errors_total	Counter	service, scenario, step, error_type_name	The total number of journey errors. It increments at the exact point of failure, tagged with your custom error_type_name.

Example Scrape Output

A realistic raw response from curl http://localhost:10050/metrics:

# HELP synthetic_http_status_code HTTP response status code returned by the API endpoint.
# TYPE synthetic_http_status_code gauge
synthetic_http_status_code{endpoint="https://my-e-commerce-app.example.com/api/health",service="my-e-commerce-app"} 200

# HELP synthetic_ssl_cert_expiry_timestamp_seconds Unix timestamp of the TLS certificate expiration date.
# TYPE synthetic_ssl_cert_expiry_timestamp_seconds gauge
synthetic_ssl_cert_expiry_timestamp_seconds{endpoint="https://my-e-commerce-app.example.com/api/health",service="my-e-commerce-app"} 1.7839584e+09

# HELP synthetic_ui_step_duration_seconds Elapsed time in seconds for each UI journey step.
# TYPE synthetic_ui_step_duration_seconds gauge
synthetic_ui_step_duration_seconds{action="goto",scenario="Login Flow",step="navigate_to_login",service="my-e-commerce-app"} 1.204
synthetic_ui_step_duration_seconds{action="fill",scenario="Login Flow",step="fill_username",service="my-e-commerce-app"} 0.087
synthetic_ui_step_duration_seconds{action="click",scenario="Login Flow",step="click_login_button",service="my-e-commerce-app"} 0.341

# HELP synthetic_ui_journey_success 1 if the full UI journey completed without errors, 0 otherwise.
# TYPE synthetic_ui_journey_success gauge
synthetic_ui_journey_success{scenario="Login Flow",service="my-e-commerce-app"} 1

# HELP synthetic_ui_journey_errors_total Total number of UI journey failures, labelled by the step's error_type_name.
# TYPE synthetic_ui_journey_errors_total counter
synthetic_ui_journey_errors_total{error_type_name="navigation_failed",scenario="Login Flow",step="navigate_to_login",service="my-e-commerce-app"} 0

How to use these metrics (PromQL)

Once Prometheus scrapes these metrics, you can create highly effective alerts and dashboards using PromQL.

Example 1: Alerting on Journey Failure

If synthetic_ui_journey_success is 0, the critical flow is broken right now.

synthetic_ui_journey_success == 0

Example 2: Calculating Error Rates

To see how often a specific error occurs over time (e.g., login buttons failing), use the rate() function on the error counter:

rate(synthetic_ui_journey_errors_total{error_type_name="login_failed"}[$__rate_interval]) > 0

(Note: We use Grafana's dynamic [$__rate_interval] variable instead of a hardcoded [5m] to prevent data gaps or aliasing when zooming out in your Grafana dashboard.)

Example 3: Alerting on expiring SSL Certificates

To trigger an alert if any SSL certificate will expire in less than 7 days (604800 seconds):

(synthetic_ssl_cert_expiry_timestamp_seconds - time()) < 604800

TIP

We strongly recommend using our official Grafana Dashboard to visualize all these metrics and queries instantly. See the Grafana Dashboard page for instructions on how to import it.