Monitoring Eraser.io with Vigilmon

Eraser.io is a diagramming and technical documentation tool built for software engineering teams. It combines architecture diagrams, entity-relationship diagrams, and sequence diagrams in a collaborative workspace that teams use for system design and code review. Self-hosted or API-integrated Eraser.io deployments give teams control over their documentation infrastructure — but they also mean owning the uptime. Vigilmon monitors your Eraser.io endpoints so you know about failures before your engineers hit a blank diagram canvas.

What You'll Set Up

• HTTP uptime monitor for the Eraser.io web application
• API endpoint health check for diagram synchronization
• TCP port check for network-level connectivity
• SSL certificate expiry alerts for your Eraser.io domain
• Heartbeat monitoring for background diagram rendering jobs

Prerequisites

• Self-hosted Eraser.io instance or API integration endpoint running
• Eraser.io accessible over HTTP or HTTPS on a domain or IP
• A free Vigilmon account

Step 1: Monitor the Eraser.io Web Application

The Eraser.io frontend is where your engineers create and collaborate on system design documents. If this endpoint is unreachable, teams can't load diagrams or edit technical specs.

1. Log in to vigilmon.online and click Add Monitor.
2. Set Type to HTTP / HTTPS.
3. Enter your Eraser.io URL: https://eraser.yourdomain.com.
4. Set Check interval to 1 minute.
5. Set Expected HTTP status to 200.
6. Click Save.

If Eraser.io is deployed behind a reverse proxy (nginx, Caddy, Traefik), the HTTP check confirms both the proxy and the Eraser.io application process are healthy. A 502 Bad Gateway signals that the application container has crashed while the proxy remains active.

Step 2: Monitor the Eraser.io API Health Endpoint

Eraser.io exposes an API that powers diagram synchronization and collaborative editing. Monitor it directly to catch backend failures that don't affect the frontend immediately:

1. Add Monitor → HTTP / HTTPS.
2. URL: https://eraser.yourdomain.com/api/health (or your configured health route).
3. Set Expected HTTP status to 200.
4. Under Advanced, set Expected body contains to ok or whatever your health endpoint returns.
5. Set Check interval to 2 minutes.
6. Click Save.

API health checks catch backend degradation — database connectivity issues, background job failures, or memory exhaustion — before the frontend shows errors to users. A healthy HTML response from the frontend with a failing API endpoint means diagrams will load but won't save.

Step 3: Add a TCP Port Check

Eraser.io typically serves on port 443. A TCP port monitor provides a connectivity check independent of the HTTP and application layers:

1. Add Monitor → TCP Port.
2. Host: eraser.yourdomain.com, Port: 443 (or 80 for HTTP-only deployments).
3. Set Check interval to 2 minutes.
4. Click Save.

TCP checks catch network-level failures — firewall rule changes, container port binding errors, or load balancer misconfigurations — before any HTTP response is generated. This is especially useful for catching ingress controller failures in Kubernetes deployments where the application pod is healthy but unreachable from outside the cluster.

Step 4: Add SSL Certificate Monitoring

A lapsed TLS certificate blocks all Eraser.io access with a browser security error. Collaborative diagram tools see immediate impact when certificates expire — all engineers are blocked at the same time.

1. Open your Eraser.io HTTP / HTTPS monitor.
2. Enable Monitor SSL certificate under the SSL section.
3. Set Alert when certificate expires in less than 21 days.
4. Click Save.

A 21-day alert window provides enough lead time to resolve Let's Encrypt auto-renewal failures, DNS propagation delays, or certificate authority validation issues before users are impacted.

Step 5: Heartbeat Monitoring for Diagram Rendering Jobs

Eraser.io background jobs handle diagram-to-image exports, document indexing, and async collaborative operations. Use Vigilmon's cron heartbeat to confirm these background processes are running:

1. In Vigilmon, click Add Monitor → Cron Heartbeat.
2. Set the expected ping interval to match your background worker schedule (e.g. 60 minutes).
3. Copy the heartbeat URL (e.g. https://vigilmon.online/heartbeat/abc123).
4. Instrument your background worker to ping Vigilmon after each successful run:

#!/bin/bash
# Confirm Eraser.io background rendering job completed
node /app/workers/diagram-export.js && \
  curl -s https://vigilmon.online/heartbeat/abc123

For containerized workers:

services:
  eraser-worker:
    image: eraserio/worker
    command: sh -c "node worker.js && curl -s https://vigilmon.online/heartbeat/abc123"
    restart: unless-stopped

If the heartbeat stops arriving, Vigilmon alerts you that the export pipeline has silently failed — catching job crashes that don't produce HTTP errors and wouldn't otherwise trigger uptime alerts.

Step 6: Configure Alert Channels

1. Go to Alert Channels in Vigilmon and add Slack, email, or a webhook to your on-call system.
2. Set Consecutive failures before alert to 2 on the main Eraser.io monitor — transient container restarts and brief probe misses can cause single false positives.
3. Use Maintenance windows to suppress alerts during deployments:

# Pause alerts during upgrade
curl -X POST https://vigilmon.online/api/maintenance \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{"monitor_id": "abc123", "duration_minutes": 10}'

docker pull eraserio/app && docker compose up -d

Summary

| Monitor | Target | What It Catches | |---|---|---| | Web application | https://eraser.yourdomain.com | Frontend down, proxy failure | | API health endpoint | /api/health | Backend degradation, sync failures | | TCP port | :443 | Network-level connectivity failure | | SSL certificate | Eraser.io domain | Certificate renewal failure | | Cron heartbeat | Heartbeat URL | Background rendering job crash |

Eraser.io puts architecture diagrams and system design docs at the center of your engineering workflow — when it's unavailable during an incident review or system design session, teams are blocked. With Vigilmon watching the frontend, API, TCP layer, SSL certificate, and background jobs, you'll know about failures in real time instead of hearing about them mid-meeting.