You've launched a website, an application, or an API. It's working well... for now. But how do you know if it keeps working when you're not there? How do you get alerted before your users call to complain? That's where monitoring comes in.
Monitoring means automatically watching your services to detect problems as soon as they occur. Instead of learning that a site is down from an angry tweet or furious client email, you receive an alert within minutes of the outage.
This guide explains the fundamentals of monitoring: why it's important, what to watch, and how to set up effective monitoring even as a beginner. No unnecessary jargon, just the essential basics.
Why Monitor?
The reasons that make monitoring indispensable:
- Detect outages quickly: Without monitoring, you discover problems when users complain. With monitoring, you're alerted within minutes.
- Reduce impact: The faster you detect a problem, the faster you resolve it. A 5-minute outage is much less serious than a 5-hour outage.
- Prove availability: Monitoring provides historical data. Useful for proving your SLA to clients or identifying problem patterns.
- Sleep peacefully: Knowing you'll be alerted if there's a problem lets you disconnect mentally. No need to check manually at midnight.
Types of Monitoring
The different monitoring approaches:
- Availability (Uptime) Monitoring: Checks that your service responds. Simple: is the site accessible or not? This is the bare minimum.
- Performance Monitoring: Measures response times. A slow site is almost as problematic as a down site for user experience.
- SSL Monitoring: Watches for SSL certificate expiration. An expired certificate = site marked "not secure" = trust lost.
- DNS Monitoring: Verifies that your DNS records still point to the right place. An unauthorized change could indicate hacking.
- Heartbeat / Cron: Monitors scheduled tasks (backups, imports). If a job doesn't run, you're alerted.
Where to Start?
Steps to set up your first monitoring:
- Identify critical services: What absolutely must work? Main site, API, admin interface, payment process... Prioritize.
- Create basic monitors: Start simple: an HTTP monitor that checks your homepage responds with a 200 code.
- Configure alerts: Define where to receive alerts: email, SMS, Slack. Make sure someone will receive and read the notifications.
- Define frequency: Every minute for critical services, every 5 minutes for others. Adjust based on importance.
- Test: Trigger a controlled problem (maintenance) and verify the alert arrives. Better to test now than during a real outage.
Key Metrics
Essential indicators to monitor:
- Availability (Uptime): Percentage of time the service works. Aim for minimum 99.9% (8.77h max downtime per year).
- Response time: Time to receive a response from the server. Under 500ms is good, under 200ms is excellent.
- Error rate: Percentage of requests that fail (5xx codes). Should stay close to 0%.
- Days until SSL expiry: Number of days before your certificate expires. Alert at least 30 days before.
Configuring Alerts
Best practices for effective alerts:
- Avoid false positives: Use double verification. A single failed check doesn't trigger an alert, two consecutive ones do.
- Choose the right channel: Email for non-urgent alerts, SMS or call for emergencies. Slack for the team during business hours.
- Define who's responsible: Who receives alerts? Who's on-call on weekends? Document and share.
- Avoid fatigue: Too many alerts = ignored alerts. Only configure what's truly critical for intrusive notifications.
Beginner Mistakes to Avoid
Classic monitoring pitfalls:
- Only monitoring the homepage: The home page can work while checkout is broken. Monitor critical paths.
- Ignoring response times: A site that responds 200 in 10 seconds is a broken site for users. Monitor latency.
- No SSL monitoring: Forgetting to renew an SSL certificate happens more often than you think. Automate alerts.
- Misconfigured alerts: Adding your personal email and going on vacation. Make sure someone active receives alerts.
First Monitoring Checklist
- List all critical services to monitor
- Create a monitor for each critical service
- Configure alerts (email + SMS for emergencies)
- Enable SSL monitoring for all HTTPS sites
- Test that alerts actually arrive
- Document who receives alerts and when
Frequently Asked Questions
How many monitors should I create?
At minimum: one per critical service. A simple site might only need 2-3 monitors. A complex application might have dozens.
How often should I check?
Critical services: every minute. Secondary services: every 5 minutes. Scheduled tasks (cron): according to their frequency.
Is free monitoring enough?
For starting with a small site, yes. Free plans have limitations (number of monitors, frequency). Scale according to your needs.
Can I monitor from multiple locations?
Yes, and it's recommended. MoniTao checks from multiple regions to avoid false positives related to local network issues.
How do I know my monitoring is working?
Test it. Temporarily put your site in maintenance and verify the alert arrives. Do this test regularly.
What to do when I receive an alert?
Verify the problem, diagnose (check logs), resolve, document. Use our diagnostic guides for common errors.
Get Started!
Monitoring doesn't have to be complicated. Start simple with a few monitors on your critical services, and gradually expand. The important thing is to start and be alerted to problems.
MoniTao is designed to be easy to use. Create your free account, add your first monitor in 2 minutes, and you'll never be the last to know about an outage again.
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