What Is Uptime Monitoring? A Beginner's Guide
Uptime monitoring checks whether your website or application is reachable and working — automatically, on a schedule, from outside your network. When it detects a problem, it alerts you. Here's everything you need to know to get started.
What does "uptime" mean?
Uptime is the percentage of time your service is available and working correctly. If your website is accessible 24 hours a day, 7 days a week, your uptime is 100%. If it goes down for 44 minutes in a month, your uptime is approximately 99.9%.
The opposite of uptime is downtime: the periods when your service isn't responding, is returning errors, or is too slow to be usable. Downtime costs money — in lost sales, wasted ad spend, support time, and damaged user trust.
How uptime monitoring works
An uptime monitor is a program that regularly makes a request to your website or API and checks the response. Here's the basic cycle:
- Check: The monitoring service sends an HTTP request to your URL (e.g.
https://yoursite.com) from its own servers — not from your computer. - Evaluate: It checks the response: Did it get a response at all? What was the HTTP status code? How long did it take? Does the response body contain expected content?
- Record: The result (up or down, response time, status code) is saved to a database for historical tracking.
- Alert: If the check fails — or fails multiple times in a row — the monitor sends you an alert by email, Slack, text message, or another channel you've configured.
This cycle repeats on a schedule. PingBase checks every minute. Some tools check every 5 minutes. The shorter the interval, the faster you find out about problems.
What can uptime monitoring check?
The most common check is an HTTP monitor — it requests a URL and checks the response. But monitoring tools can check more than just websites:
| Monitor type | What it checks |
|---|---|
| HTTP / HTTPS | Website or API endpoint availability, status code, response body content |
| SSL certificate | Certificate expiry date — alerts you before it expires and causes browser warnings |
| DNS | Whether your domain resolves to the expected IP address |
| Heartbeat / cron | Whether a scheduled job is running — alerts if the job stops checking in |
| TCP / port | Whether a specific port is open on a server (database, mail server, etc.) |
Why run checks from an external server?
The monitoring tool must run its checks from a server that's separate from your application. If it ran from your own server, it would go down at the same time your site goes down — and never detect the outage.
External monitoring simulates a real user visiting your site from the internet. It catches the same problems a visitor would see: the server not responding, a DNS failure, an expired SSL certificate causing a browser security warning.
For extra reliability, some tools (including PingBase) run checks from multiple locations simultaneously. If the check fails from all locations, the site is really down. If it only fails from one location, it might be a regional network issue rather than a real outage — and you won't get a false alarm.
What happens when something goes wrong?
When the monitor detects a failure, it sends you an alert. The alert includes:
- Which monitor failed
- What URL or endpoint was being checked
- What error was returned (timeout, 500 error, connection refused)
- When the failure was first detected
When the site recovers, you get a second alert: a recovery notification. This closes the incident and tells you how long the outage lasted.
Most monitoring tools let you configure where alerts go: email, Slack, Discord, Telegram, PagerDuty, or a custom webhook. You can have multiple channels — for example, Slack for your team during business hours and a phone alert for overnight critical incidents.
What is a status page?
A status page is a public webpage that shows your service's current status and uptime history. It's typically at a URL like status.yourcompany.com or yourcompany.com/status.
When your site goes down, users can check the status page to see if you're aware of the problem. Instead of filing support tickets or tweeting at you, they see "We're aware of this issue and working on a fix." That small communication reduces panic and support load.
Most uptime monitoring tools — including PingBase — include a status page as part of the service. Your monitors feed into the status page automatically.
How do I get started?
Setting up basic uptime monitoring takes about 5 minutes:
- Sign up for a monitoring service (PingBase has a free tier with 5 monitors)
- Add a monitor for your main URL
- Configure an alert channel (email is easiest to start)
- Create a public status page and link to it from your app
Once that's running, you can add more monitors: your SSL certificate, your API health endpoint, any critical pages. Most products need 3–5 monitors to cover the basics.
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