Uptime Monitoring: Why and How to Set It Up

Why Monitor Uptime

Uptime (availability) is the time during which a website or service is accessible and functioning correctly. Every minute of downtime means lost revenue, customers, and reputation. Research shows that one minute of downtime costs large businesses an average of $5,600.

Uptime monitoring lets you detect problems in minutes rather than hearing about them from frustrated customers hours later.

What to Monitor

Main Website

Check the homepage and key sections. Don't just verify the HTTP status code — check for expected content in the response.

API

Monitor critical API документацию endpoints. Check not just availability but response correctness (JSON structure, expected fields).

Databases

Database failure is the most common cause of serious incidents. Monitor connectivity and response time.

Third-Party Services

Payment gateways, CRM, email providers, CDN — any external service your business depends on.

SSL Certificates

An expired certificate means complete unavailability to users. Monitor expiration with the Enterno.io SSL Checker.

Check Types

HTTP/HTTPS Check

The most common type. Sends an HTTP request and verifies status code, response time, and content.

• Response code (200, 301, 500...)
• Response time (should be under threshold)
• Content presence (keyword check)
• SSL certificate validity

Ping (ICMP)

Checks server availability at the network level. Fast and lightweight but doesn't verify web application functionality. Use the Enterno.io Ping Test.

TCP/Port Check

Checks availability of a specific port: 3306 (MySQL), 6379 (Redis), 5432 (PostgreSQL). Useful for monitoring internal services.

DNS Check

Verifies DNS record correctness and resolution time. Use Enterno.io DNS Lookup.

Check Frequency

• Every 30 seconds — for critical services (payment systems, main API)
• Every minute — for the main website and key pages
• Every 5 minutes — for internal services and less critical pages
• Every 15-30 minutes — for secondary services

Keep in mind that too-frequent checks generate traffic and may be blocked by WAF.

Alert Configuration

Key principles:

• Multi-location confirmation — a single failure may be a network glitch. Alert only if the check fails from 2+ locations.
• Alert delay — wait for 2-3 consecutive failures before notifying.
• Proper channels — Telegram/SMS for critical, email for warnings.
• Escalation — if the issue isn't resolved in 15 minutes, notify the next person in the chain.

Status Page

A public status page informs users about current service status and incidents. It reduces support load and increases trust.

A status page should include:

• Current status of each service (Operational, Degraded, Down)
• Incident history with timeline
• Planned maintenance
• Update subscriptions (email, RSS, webhook)
• Uptime for the last 30/90 days

SLA and Uptime Calculation

SLA (Service Level Agreement) defines the guaranteed availability level:

• 99% — up to 7.3 hours of downtime per month
• 99.9% — up to 43.8 minutes of downtime per month
• 99.95% — up to 21.9 minutes of downtime per month
• 99.99% — up to 4.3 minutes of downtime per month

Formula: uptime% = (total_minutes - downtime_minutes) / total_minutes * 100

Start Monitoring with Enterno.io

Set up Enterno.io uptime monitoring in minutes. Add your website URL, choose check frequency and notification channels. The system will check availability and notify you of issues. Use the monitors dashboard to view all service statuses.

Summary

Uptime monitoring is the bare minimum for any web project. Monitor not just HTTP availability but also APIs, databases, SSL, and third-party services. Set up alerts with multi-location confirmation. Publish a status page for transparency. Remember: without monitoring, you'll be the last to know about problems.