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Zenovay
Pro Plan15 minutesIntermediate

Page Load Performance

Monitor and analyze page load times, resource loading, and navigation performance metrics. Learn about performance in this error tracking guide.

performancepage-loadtimingttfbresources
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Monitor detailed page load performance metrics to identify bottlenecks and optimize user experience.

Performance Metrics Overview

Zenovay captures Navigation Timing API data:

DNS    TCP    TLS    TTFB    Content    DOM    Load
|------|------|------|-------|----------|------|
0     50    100    150     400        800    1200ms
MetricDescriptionTarget
DNS LookupDomain resolution time< 20ms
TCP ConnectConnection establishment< 50ms
TLS HandshakeSSL negotiation< 100ms
TTFBTime to First Byte< 200ms
Content DownloadHTML transfer time< 100ms
DOM ProcessingParse and execute< 500ms
Load CompleteAll resources loaded< 3s

Key Metrics Explained

Time to First Byte (TTFB): Server processing time + network latency

TTFB = responseStart - requestStart

First Contentful Paint (FCP): First text or image painted

FCP = First content visible

DOM Interactive: HTML parsed, ready for JavaScript

domInteractive = DOM ready for scripts

DOM Complete: All resources (images, styles) loaded

domComplete = Page fully loaded

Performance Dashboard

Overview

Navigate to PerformancePage Load:

Page Load Performance (Last 7 Days)

Avg Load Time:  2.4s
Median TTFB:    185ms
Avg DOM Ready:  1.2s

Trend: ↓ 12% faster than last week

Timing Breakdown

Visual waterfall showing timing stages:

DNS Lookup      ██░░░░░░░░░░░░░░░░░░  45ms
TCP Connection  ███░░░░░░░░░░░░░░░░░  62ms
TLS Handshake   █████░░░░░░░░░░░░░░░  108ms
TTFB            ███████░░░░░░░░░░░░░  185ms
Content         █░░░░░░░░░░░░░░░░░░░  28ms
DOM Processing  ██████████░░░░░░░░░░  520ms
Load Complete   ████████████████████  2.4s

Distribution View

See performance distribution:

Load Time Distribution

< 1s    ████████████████████ 32%
1-2s    ██████████████████   28%
2-3s    ████████████████     25%
3-5s    ████████             10%
> 5s    ██                   5%

Page-Level Analysis

Slowest Pages

Identify problematic pages:

PageLoad TimeTTFBViews
/products4.2s890ms15,230
/checkout3.8s420ms8,450
/search3.5s310ms12,100
/blog2.9s180ms22,500
/home2.1s150ms45,000

Page Detail View

Click a page for detailed breakdown:

/products Performance Analysis

Timing Breakdown:
├── Server Response (TTFB)     890ms  ← Issue
│   └── Backend processing slow
├── HTML Download              45ms
├── CSS/JS Loading            320ms
│   ├── main.css              85ms
│   ├── vendor.js            180ms  ← Large bundle
│   └── app.js               55ms
├── Images                    520ms
│   └── 12 images, avg 43ms
└── DOM Complete             1,850ms

Recommendations:
• TTFB is high - check server/database
• vendor.js is large - consider code splitting

Resource Timing

Resource Waterfall

See all resources loaded:

Resource                        Start   Duration   Size
main.css                        180ms   85ms       45KB
vendor.js                       200ms   180ms      312KB
app.js                          380ms   55ms       89KB
hero-image.webp                 280ms   420ms      156KB
analytics.js (third-party)      100ms   95ms       12KB
font.woff2                      250ms   120ms      28KB

Resource Categories

CategoryCountTotal SizeTotal Time
Scripts5423KB450ms
Stylesheets378KB120ms
Images12856KB680ms
Fonts256KB180ms
XHR/Fetch415KB320ms

Third-Party Impact

Identify slow third-party resources:

Third-Party Resources

Origin                    Resources   Time    Impact
fonts.googleapis.com      2           180ms   Medium
cdnjs.cloudflare.com     3           95ms    Low
www.googletagmanager.com 1           250ms   High ← Review
connect.facebook.net     1           320ms   High ← Consider removing

Server Performance (TTFB)

TTFB Analysis

TTFB Distribution

< 100ms   ██████████████       42%  ✓ Excellent
100-200ms ████████████         35%  ✓ Good
200-500ms ██████               18%  ⚠ Needs work
500ms-1s  ██                   4%   ✗ Slow
> 1s      █                    1%   ✗ Very slow

TTFB by Endpoint

EndpointAvg TTFBP95 TTFBNotes
/api/products450ms1.2sDatabase query slow
/api/search280ms890msConsider caching
/api/user85ms150msGood
Static pages45ms120msExcellent

Geographic TTFB

TTFB by Region

North America   ██████████████████   120ms
Europe          ████████████████     180ms
Asia Pacific    ████████████         320ms  ← Consider CDN
South America   ██████████           420ms  ← Consider CDN

Page Load Types

TypeDescription% Traffic
NavigateDirect navigation45%
ReloadPage refresh20%
Back/ForwardBrowser navigation25%
PrerenderSpeculative load10%

Performance by Navigation

Navigation Type    Avg Load    Median
Navigate           2.4s        2.1s
Reload             1.8s        1.5s    ← Cache benefit
Back/Forward       0.8s        0.6s    ← BFCache benefit

Optimization Recommendations

Server-Side

IssueDetectionSolution
Slow TTFBTTFB > 200msOptimize queries, add caching
No compressionLarge HTMLEnable gzip/brotli
No HTTP/2Multiple connectionsUpgrade server
Far serverHigh latency by regionUse CDN

Client-Side

IssueDetectionSolution
Large bundlesJS > 200KBCode splitting
Render blockingCSS in headCritical CSS
Many requests> 50 resourcesBundling, HTTP/2
Large images> 200KBOptimize, WebP

Caching

IssueDetectionSolution
No cachingCache-Control missingSet cache headers
Short cacheFrequent revalidationLonger max-age
No service workerNo offlineImplement SW

Comparing Periods

Week over Week

This Week vs Last Week

Load Time:  2.4s → 2.1s  ↓ 12% better
TTFB:       185ms → 170ms ↓ 8% better
FCP:        1.1s → 1.0s  ↓ 9% better

Changes:
• Image optimization deployed
• CDN enabled for Europe

Release Comparison

Compare performance across releases:

  1. Select two releases
  2. View metric comparison
  3. Identify regressions
  4. Correlate with changes

Real-Time Monitoring

Live Performance

Watch performance in real-time:

  • Current active sessions
  • Live page load times
  • Geographic distribution
  • Error rates

Anomaly Detection

Automatic alerts for:

  • Sudden TTFB increase
  • Load time spikes
  • Unusual traffic patterns
  • Performance degradation

Export & Reporting

Export Options

  • CSV: Raw timing data
  • PDF: Performance report
  • API: Programmatic access

Scheduled Reports

  1. Go to ReportsScheduled
  2. Create "Weekly Performance Report"
  3. Select metrics and pages
  4. Set recipients and schedule

Integration with CI/CD

Performance Budgets

Set budgets in your build:

// performance-budget.json
{
  "budgets": [
    {
      "path": "/*",
      "metrics": {
        "lcp": 2500,
        "fcp": 1800,
        "ttfb": 200
      }
    }
  ]
}

Lighthouse CI

Compare Lighthouse scores with real-user data.

Best Practices

Monitoring Strategy

  1. Set baselines: Establish current performance
  2. Define targets: Based on user expectations
  3. Monitor trends: Not just snapshots
  4. Segment data: Device, geography, page type
  5. Act on insights: Turn data into improvements

Quick Wins

  1. Enable compression (gzip/brotli)
  2. Optimize images (WebP, proper sizing)
  3. Set cache headers
  4. Use a CDN
  5. Remove unused code

Ongoing Optimization

  1. Regular audits
  2. Performance budgets
  3. Monitoring and alerts
  4. Team awareness

Troubleshooting

Missing Data

Check:

  • Script loading correctly
  • Sufficient traffic
  • No ad blockers affecting script

Inconsistent Numbers

Consider:

  • Sample rate settings
  • Traffic mix changes
  • Bot traffic filtering

High Variance

Normal for:

  • Mobile traffic
  • Global users
  • Peak traffic periods

Next Steps

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