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How to Monitor Your htmx Application with Vigilmon (Uptime + Server Health)

#htmx #monitoring #webdev #uptime

How to Monitor Your htmx Application with Vigilmon (Uptime + Server Health)

htmx is back-to-basics: HTML over the wire, AJAX without JavaScript frameworks. If you're building with htmx, your server does the heavy lifting — which means your server is the critical dependency.

This guide shows you how to monitor an htmx application with Vigilmon to catch server downtime, slow responses, and SSL issues before your users notice.

Why htmx Apps Need External Monitoring

With htmx, when your server goes down:

  • All page interactions stop working (HTML fragments are not returned)
  • Users see partial page updates fail silently or see errors
  • There is no client-side JS to show a helpful offline message

External monitoring gives you visibility that your server is alive and responding before users experience broken interactions.

What to Monitor in an htmx App

1. The Main Page

Monitor your entry point:

https://yourdomain.com/
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2. A Dedicated Health Endpoint

Add a /health route to your server-side framework:

Python Flask:

@app.route('/health')
def health():
    try:
        db.session.execute('SELECT 1')
        return {'status': 'ok'}, 200
    except Exception:
        return {'status': 'error'}, 503
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Go:

http.HandleFunc("/health", func(w http.ResponseWriter, r *http.Request) {
    if err := db.Ping(); err != nil {
        w.WriteHeader(http.StatusServiceUnavailable)
        return
    }
    w.Write([]byte(`{"status":"ok"}`))
})
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Ruby on Rails:

get '/health', to: proc { [200, {}, ['ok']] }
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Setting Up Vigilmon Monitors

  1. Sign in at vigilmon.online
  2. Click New Monitor > HTTP/HTTPS
  3. For each endpoint set the URL, interval (1 min for health, 5 min for pages), and expected status 200
  4. Add an SSL monitor for your domain

Common htmx Failure Modes Vigilmon Catches

Failure What Users See What Vigilmon Catches
Server process crashed All interactions fail HTTP check fails
Database connection lost Queries fail, errors returned /health returns 503
Memory exhaustion Slow or hung responses Response time threshold
SSL certificate expired Browser blocks the page SSL monitor alert
Deployment error 500 errors returned Non-200 status check

Summary

htmx applications are server-centric by design. With Vigilmon:

  1. Monitor your main page and key endpoints
  2. Add a /health route that checks your DB connection
  3. Add an SSL monitor for your domain
  4. Set response time thresholds (2s for fragment endpoints)
  5. Configure Slack/email alerts

Setup takes under 5 minutes.

Start monitoring your htmx app with Vigilmon - free

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