Home › Network Ports

Port 9090 (Prometheus) — What It Is and How to Use It

Port 9090 is most commonly associated with Prometheus, an open-source monitoring and alerting toolkit. It serves as the default HTTP port for the Prometheus server, where it exposes its web UI and receives metrics from configured targets.

Last updated: 2026-06-11

RECOMMENDED

Gear Up: Mechanical Keyboards for Developers

Reduce fatigue and type faster with premium mechanical keyboards. Check out top picks for software engineers.

Shop Developer Gear →
Port Number 9090
Protocol Prometheus

Common Use Cases

  • Accessing the Prometheus web interface for querying metrics and managing configurations.
  • Scraping metrics from various exporters (e.g., Node Exporter, cAdvisor) configured to send data to the Prometheus server.
  • Receiving alerts from Alertmanager, although Alertmanager typically uses its own dedicated ports.
  • Integrating with other monitoring and visualization tools like Grafana.

Interactive Command Builder

nc -zv example.com 9090

Check if Port 9090 is Open

sudo netstat -tulnp | grep 9090
netstat -ano | findstr :9090
⚠️ Security Note: Exposing port 9090 directly to the internet without proper authentication and authorization can be a security risk, as it allows unauthorized access to your monitoring data and potentially sensitive system information. It's recommended to place Prometheus behind a reverse proxy with authentication or restrict access via firewalls.

Related Ports

Port 9091 Port 9100 Port 9300 Port 9323

Frequently Asked Questions

Is port 9090 dangerous to leave open?

Yes, leaving port 9090 open to the public internet without proper security measures (like a firewall, VPN, or reverse proxy with authentication) is dangerous. It exposes your monitoring data and potentially sensitive system metrics to anyone who can access the port.

What service uses port 9090?

The primary service that uses port 9090 is the Prometheus server. It's the default port for its web interface and for receiving scraped metrics.