What is Uptime Monitoring?
A complete guide to monitoring website availability, detecting outages, and keeping services reliable.
Uptime monitoring is the practice of regularly checking if your website, API, or service is available and working correctly. When something breaks, you get alerted immediately—not from an angry customer, but from your monitoring tool.
How uptime monitoring works
At its core, uptime monitoring is simple:
- Regular checks – A monitoring service sends requests to your website or API every 1-5 minutes
- Validation – The service checks if the response is successful (status code 200), fast enough, and contains expected content
- Alerting – If something fails, you get notified via email, SMS, Slack, PagerDuty, or other channels
- Recovery notification – When the issue is resolved, you're notified that service is restored
Most monitoring services run checks from multiple geographic locations to reduce false positives from regional network issues.
Types of uptime monitoring
HTTP/HTTPS monitoring
The most common type. Checks if your website or API endpoint responds to HTTP requests. Can verify status codes, response time, and even specific content on the page.
Ping (ICMP) monitoring
Checks if a server is reachable at the network level. Simpler than HTTP checks, useful for infrastructure monitoring.
Port monitoring
Checks if specific ports are open and accepting connections. Useful for databases, mail servers, and other services that don't use HTTP.
SSL certificate monitoring
Tracks SSL certificate expiration and validity. Get alerts before certificates expire and cause browser warnings.
Heartbeat/cron monitoring
Instead of checking endpoints, your jobs ping the monitoring service. If a job doesn't check in on schedule, you get alerted. Essential for cron jobs, scheduled tasks, and background workers.
DNS monitoring
Checks if DNS records resolve correctly. Catches DNS propagation issues, hijacking attempts, or accidental changes.
Keyword monitoring
Checks for specific text on a page. Useful for catching error messages, "out of stock" notices, or content that shouldn't change.
Why uptime monitoring matters
Faster incident detection
Without monitoring, outages are often discovered by customers—the worst way to learn about problems. Monitoring detects issues in minutes, giving you a head start on resolution.
Customer trust
Downtime damages reputation. Quick detection and communication (via status pages) shows customers you take reliability seriously.
SLA compliance
Many contracts include uptime guarantees. Monitoring gives you data to prove compliance and catch issues before SLA violations.
Historical data
Good monitoring tools keep history. See patterns, identify recurring issues, and track improvement over time.
What to look for in a monitoring service
- Check frequency – How often can you run checks? Every minute? Every 5 minutes?
- Geographic distribution – Checks from multiple regions reduce false positives
- Alert channels – Email, SMS, Slack, PagerDuty, webhooks—route alerts where your team actually looks
- Status pages – Public pages to communicate with customers during incidents
- Team features – Multi-user access, permissions, and easy onboarding for team members
- Integrations – Connect with your existing tools and workflows
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- 1-minute check intervals
- Multiple check locations
- Email, Slack, SMS alerts