Vigilmon vs Sentry: Uptime Monitoring vs Error Tracking (What Is the Difference?)

When your app breaks, two different questions get asked simultaneously:

1. Is it down? (uptime monitoring)
2. What went wrong? (error tracking)

Sentry answers question 2. Vigilmon answers question 1. This article explains why they are complementary, not competing, and what each one is actually for.

What Sentry Does

Sentry is an error tracking and performance monitoring platform. It instruments your application code and captures:

• Unhandled exceptions with full stack traces
• Performance traces (slow database queries, slow API calls)
• User session replays
• Release health and crash rates

Sentry tells you what broke inside your app — the exception type, the line of code, the user who was affected, and what they were doing when it happened.

Sentry sees the inside of your application.

What Vigilmon Does

Vigilmon is an external uptime monitoring service. It sends HTTP requests to your endpoints from multiple geographic regions and alerts you when:

• An endpoint returns a non-2xx status code
• A response takes longer than your threshold (e.g., 10 seconds)
• An endpoint becomes unreachable (DNS failure, network timeout)
• An SSL certificate is about to expire

Vigilmon tells you whether your app is reachable at all — from the user perspective, not from inside your infrastructure.

Vigilmon sees what your users see.

Why You Need Both

Here is the key insight: your app can fail without throwing any exceptions, and exceptions can fire without your app being down.

Scenario 1: Down but no Sentry alert

Your load balancer misconfigures after a deploy. Requests to /api/products return 502 Bad Gateway from the load balancer — never reaching your app. Sentry sees nothing (the request never hit application code). Vigilmon fires an alert in 60 seconds.

Scenario 2: Sentry alert but app is up

A batch job fails with an unhandled exception processing a specific user record. Sentry captures it with full context. Your app is otherwise running normally — Vigilmon sees all green.

Scenario 3: Both fire together

Your database goes down. API calls start throwing exceptions (Sentry captures them). Endpoints start returning 500 (Vigilmon detects the downtime). You get both alerts and now have the full picture.

Feature Comparison

Recommended Setup

For a production application, use both:

Vigilmon:

• Monitor your /health endpoint every 1 minute from 3+ regions
• Add monitors for your most critical API routes
• Set up a public status page at status.yourapp.com
• Alert your on-call Slack channel on first failure

Sentry:

• Instrument your backend with the Sentry SDK
• Set up error alerts for new issues and regressions
• Use performance monitoring to catch slow queries

The two systems complement each other. When Vigilmon alerts that the app is down, you open Sentry to see the cascade of errors that started 30 seconds before the first monitor failure. Together, you can resolve incidents faster.

Cost Comparison

Sentry pricing is team-seat based and can get expensive at scale. The free tier includes 5K errors/month.

Vigilmon pricing is based on monitors and check frequency. The free tier covers 50 monitors at 1-minute intervals — enough for most production setups.

For a small team, you can run both on their free tiers indefinitely.

Integrating Vigilmon and Sentry

You can make them work together:

1. Use Vigilmon as your first alert — external downtime detection is faster than waiting for Sentry error volume to spike
2. Link your Sentry project in Vigilmon comments — when you acknowledge an incident in Vigilmon, link to the Sentry issue
3. Create Sentry issues from Vigilmon webhooks — use Vigilmon webhooks to create Sentry issues when a monitor goes down

Summary

• Use Sentry when you need to know what broke and why
• Use Vigilmon when you need to know if your app is up and what users experience
• Both are free to start, and together they give you complete production visibility

Set up external uptime monitoring at vigilmon.online — free, no credit card, 5-minute setup.