Monitoring Coolify with Vigilmon: Health API, Dashboard Uptime, Docker TCP Checks & SSL Alerts

Coolify is the self-hosted alternative to Heroku and Vercel: it manages your application deployments, databases, and services on your own servers. Because Coolify is the platform that deploys everything else, its own availability is critical — if Coolify's dashboard goes down, your team loses the ability to deploy, rollback, or inspect running services. If the Docker socket proxy stops responding, Coolify loses control over containers. If the SSL certificate expires, the dashboard becomes inaccessible entirely. Vigilmon gives you external visibility into Coolify's health API, web dashboard, Docker TCP proxy, and SSL certificate so you know immediately when the platform managing your deployments is itself in trouble.

What You'll Build

• A monitor on Coolify's /api/v1/healthcheck endpoint
• An HTTP monitor for the Coolify web dashboard
• A TCP monitor for the Docker socket proxy port
• SSL certificate monitoring for your Coolify domain
• An alerting setup that distinguishes API failures from dashboard or Docker proxy failures

Prerequisites

• A running Coolify instance with a public or network-reachable domain
• HTTPS configured (e.g., https://coolify.example.com)
• Docker socket proxy running (default port 2375 or your configured port)
• A free account at vigilmon.online

Step 1: Verify Coolify's Health Endpoint

Coolify exposes a dedicated health check at /api/v1/healthcheck:

curl https://coolify.example.com/api/v1/healthcheck

A healthy Coolify returns HTTP 200 with a JSON body:

{"status":"OK"}

This endpoint is unauthenticated and specifically designed for uptime monitoring — it confirms that the Coolify API server is running and its core services are operational.

Step 2: Create a Vigilmon HTTP Monitor for the Health API

1. Log in to Vigilmon → Add Monitor → HTTP.
2. URL: https://coolify.example.com/api/v1/healthcheck.
3. Check interval: 60 seconds.
4. Response timeout: 10 seconds.
5. Expected status: 200.
6. Keyword: OK.
7. Click Save.

This monitor catches:

• Coolify API server crashes or restarts
• Database connectivity failures (Coolify stores deployment state in its database)
• Configuration errors after Coolify upgrades
• PHP or runtime errors that prevent the API from responding

Because Coolify manages your production deployments, a 60-second check interval ensures you're alerted within a minute of the platform becoming unavailable — before developers notice they can't trigger deploys.

Step 3: Monitor the Coolify Web Dashboard

The health API confirms the backend is alive, but the web dashboard involves additional layers: the Vite-built frontend, session management, and the WebSocket connections that power real-time deployment logs. Monitor the dashboard independently:

1. Add Monitor → HTTP.
2. URL: https://coolify.example.com.
3. Check interval: 60 seconds.
4. Expected status: 200.
5. Keyword: Coolify.
6. Label: Coolify Dashboard.
7. Click Save.

This monitor catches reverse proxy failures, TLS termination issues, and frontend asset serving problems that wouldn't affect the health API but would prevent your team from accessing the dashboard.

Step 4: Create a TCP Monitor for the Docker Socket Proxy

Coolify communicates with Docker through a socket proxy — typically a container that exposes the Docker socket over TCP. If this proxy stops responding, Coolify loses the ability to start, stop, or inspect containers, even if its own web interface appears healthy.

1. Add Monitor → TCP.
2. Host: coolify.example.com (or the internal host if the proxy is on a separate address).
3. Port: 2375 (or your configured Docker proxy port).
4. Check interval: 60 seconds.
5. Response timeout: 10 seconds.
6. Label: Coolify Docker Socket Proxy.
7. Click Save.

Security note: If your Docker socket proxy is bound to 127.0.0.1 and not externally reachable, skip this TCP monitor or use a Vigilmon internal agent. The proxy should never be exposed to the public internet — only to Coolify's own network.

When the TCP monitor fires but the dashboard monitor is green, Coolify's UI is accessible but container operations will fail — deployments will hang or error without a clear cause until the Docker proxy is restored.

Step 5: Monitor SSL Certificates

Coolify's SSL certificate is especially important because:

• The dashboard itself uses HTTPS — expiry locks out your entire team
• Coolify provisions SSL certificates for your applications via Let's Encrypt — an expired Coolify certificate may indicate certificate management is broken more broadly

1. Add Monitor → SSL Certificate.
2. Domain: coolify.example.com.
3. Alert when expiry is within: 30 days.
4. Alert again: 14 days, 7 days, 3 days, 1 day.
5. Click Save.

If Coolify uses its built-in Caddy-based reverse proxy for automatic HTTPS (the default), a 30-day warning means Coolify's own certificate renewal has failed. Check Coolify's proxy container logs for ACME errors.

Step 6: Configure Alerting

In Vigilmon under Settings → Notifications, configure your alert channels:

| Monitor | Trigger | Action | |---|---|---| | /api/v1/healthcheck | Non-200 or OK missing | Check systemctl status coolify; inspect Coolify API logs | | Web Dashboard | Non-200 or keyword missing | Check reverse proxy; check Coolify frontend container | | Docker Socket Proxy TCP | Connection refused or timeout | Inspect Docker proxy container; check docker ps on host | | SSL certificate | < 30 days to expiry | Check Caddy/ACME logs in Coolify; force certificate renewal |

Alert after: 2 consecutive failures for HTTP monitors. 1 failure for the TCP monitor — Docker proxy connection failures are rarely transient.

Common Coolify Failure Modes and What Vigilmon Catches

| Scenario | Vigilmon monitor | |---|---| | Coolify API crash | /api/v1/healthcheck unreachable; alert within 60 s | | Database goes down | Health check returns non-200; deployment state unavailable | | Docker proxy container stops | TCP monitor fires; dashboard may still appear healthy | | Reverse proxy misconfiguration | Dashboard monitor fires; health API may be unreachable | | SSL certificate expires | SSL monitor alerts at 30-day threshold; dashboard login breaks | | Coolify upgrade failure | Health check non-200 or missing keyword; rollback needed | | Server out of disk space | Health check may degrade; new deployments fail at Docker layer | | DNS misconfiguration | All HTTP and SSL monitors fire simultaneously |

Self-hosted deployment platforms are a force multiplier — they make it easy to deploy dozens of services. But that same leverage works in reverse: if Coolify itself goes down, all deployment operations stop. Vigilmon watches Coolify's health API, web dashboard, Docker socket proxy, and SSL certificate so you know immediately when the platform that runs your infrastructure needs attention.

Start monitoring Coolify in under 5 minutes — register free at vigilmon.online.