Top 10 Website Monitoring Metrics You Should Track in 2026

By Engineering Team | 2026-06-06 | Best Practices

# Top 10 Website Monitoring Metrics You Should Track in 2026

You have a website monitoring tool running. But are you tracking the right things?

Most teams look at a single number — "is the site up?" — and call it a day. That's like checking if your car's engine is running and ignoring the temperature gauge, oil pressure, and fuel level.

Here are the 10 metrics that matter most for keeping your website healthy, plus practical advice on how to use each one.

1. Uptime Percentage (Uptime %)

What it is: The percentage of time your website is reachable and responding correctly over a given period.

Why it matters: This is the headline metric. Your customers can't use what they can't reach. An uptime below 99.9% means roughly 8.7 hours of downtime per year — that's a lot of lost revenue.

Target: 99.9% (Standard) to 99.99% (Enterprise)

How to track it:

What to watch for:

2. Response Time (Latency)

What it is: The time it takes for your server to respond to a request. Usually measured as the total time from request to full response.

Why it matters: Google's research shows that 53% of mobile users abandon a site that takes longer than 3 seconds to load. Every 100ms of latency costs Amazon 1% in revenue.

Target: Under 200ms (excellent), 200–500ms (acceptable), 500ms+ (needs work)

How to track it:

Common causes of high response time:

3. Time to First Byte (TTFB)

What it is: The time between when the browser sends a request and when it receives the first byte of the response. It measures server processing speed.

Why it matters: TTFB directly impacts user experience and Core Web Vitals. A high TTFB means your server is slow to start delivering content — even before the browser starts rendering.

Target: Under 200ms

What causes high TTFB:

How to improve it:

4. Error Rate (HTTP Status Code Distribution)

What it is: The percentage of requests that return error status codes (4xx and 5xx) versus successful ones (2xx, 3xx).

Why it matters: A low error rate is the difference between a healthy site and one that's silently failing. You can have 99.9% uptime while 10% of your API calls return errors — uptime alone doesn't tell the full story.

| Status Code | Meaning | What To Do |

|-------------|---------|-----------|

| 200–299 | Success | Good |

| 301–308 | Redirects | Verify they're intentional |

| 401–403 | Auth errors | Check login flows, API keys |

| 404 | Not found | Broken links, deleted pages |

| 500–504 | Server errors | Critical — investigate immediately |

Target: Less than 1% error rate across all requests

How to track it:

5. DNS Resolution Time

What it is: How long it takes to resolve your domain name to an IP address.

Why it matters: Every web request starts with a DNS lookup. If DNS takes 500ms, your page loads 500ms slower before a single byte is fetched — regardless of server speed.

Target: Under 50ms

Common issues:

How to optimize:

6. SSL Certificate Expiry

What it is: The number of days remaining before your SSL/TLS certificate expires.

Why it matters: An expired SSL certificate triggers browser security warnings that scare away visitors. Chrome and Safari make it difficult — and sometimes impossible — to proceed past an SSL warning.

Target: Always 30+ days from expiry (renew at 30 days)

How to track it:

The cost of an expired SSL:

7. Monitor Check Consistency (Jitter)

What it is: The variation in response times across consecutive checks. Low jitter means consistent performance. High jitter means your server is unstable.

Why it matters: A server with 300ms average but jittering from 100ms to 2500ms is worse than a server with a steady 500ms. Inconsistent performance suggests resource contention.

Target: Standard deviation under 20% of average response time

What causes jitter:

8. Domain Expiry

What it is: The number of days until your domain registration expires.

Why it matters: This is surprisingly common. Thousands of businesses lose their domain every year because they forgot to renew. When your domain expires, your website, email, and everything attached to it goes offline.

Target: Renew at 60 days before expiry. Set alerts at 90, 60, and 30 days.

Why it's worth tracking separately:

9. Content Size (Page Weight)

What it is: The total size of your web page and all its assets (HTML, CSS, JS, images, fonts).

Why it matters: Page weight directly correlates with load time, especially on mobile networks. The average web page is now over 2MB — and that's too much.

Target: Under 1MB for the initial page load

| Asset Type | Impact | Optimization |

|-----------|--------|-------------|

| Images | Usually 60-70% of page weight | WebP, lazy loading, CDN |

| JavaScript | Blocks rendering | Code splitting, defer |

| CSS | Affects first paint | Critical CSS inline, defer rest |

| Fonts | Adds 100-300KB | Subset, use WOFF2, preload |

10. Status Page Response Time (For Public Pages)

What it is: How fast your status page loads for end users.

Why it matters: When your site goes down, your status page is the first place customers go for information. If the status page is slow — or also down — you've failed the most critical communication moment of an incident.

Target: Under 1 second, even during high traffic

Best practices:

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Putting It All Together: Your Monitoring Dashboard

You don't need to watch all 10 metrics constantly. Set up a dashboard that highlights:

| Priority | Metrics | Check Frequency | Alert Threshold |

|----------|---------|----------------|----------------|

| 🔴 Critical | Uptime, Error Rate, SSL Expiry | Every minute | Any downtime, >2% errors, <30 days SSL |

| 🟡 Important | Response Time, TTFB, DNS | Every 5 minutes | P95 > 500ms, TTFB > 300ms, DNS > 100ms |

| 🔵 Nice to have | Page weight, Jitter, Domain expiry | Daily | 10%+ increase, high jitter, <60 days domain |

The Minimum Viable Monitoring Setup

If you're just starting out, track these 4 metrics first:

Everything else can come later. But don't skip these four — they're the foundation of website health.

How UptimeSaaS Helps You Track All 10

UptimeSaaS tracks most of these metrics out of the box:

Start monitoring your metrics with UptimeSaaS → — Free tier includes 25 monitors with WhatsApp alerts. No credit card required.