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Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
74
GRADE
C
FIX
3
REVIEW
3
PASS
6
INFO
2

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop
93
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
87
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
81
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
83
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

664 ms

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

1.59 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

23 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.000

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

1.39 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

2.13 s

Page Load Progression

687 ms
1.4 s
2.1 s
2.7 s
3.4 s
4.1 s
4.8 s
5.5 s
Checks
14
6 PASS 3 REVIEW 3 FIX
F
Page Weight Budget
Action
5.2 MB transferred, 126 requests
FIX
5.2 MB transferred, 126 requests
Critical::
Page weighs 14.2 MB (5.2 MB transferred)
Warning::
Images are 1.1 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 1.1 MB
Warning::
JavaScript is 835 KB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 835 KB
Info::
Fonts are 223 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 223 KB
Warning::
126 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 1.1 g CO2 per page load
5.2 MB / 2.4 MB budget
5.2 MB transferred
126 requests
1.1 g CO2 per page load
Other 2.5 MiB 48%
Images 1.1 MiB 22%
JavaScript 834.6 KiB 16%
Other 295.0 KiB 6%
Fonts 223.3 KiB 4%
Other 184.8 KiB 3%
HTML 38.8 KiB 1%
CSS 37.9 KiB 1%
Other 2.2 KiB 0%
Other 346 B 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Over budget

Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.

Why this matters

Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.

Source: web.dev

Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.

Why this matters

JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.

Source: web.dev

Subset fonts to include only used characters, or switch to system font stacks.

Why this matters

Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).

Source: web.dev font loading

Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.

Why this matters

High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.

Source: web.dev

D
Third-Party Impact
Action
83% third-party, 0 ms blocking
FIX
83% third-party, 0 ms blocking
Warning::
Third-party code accounts for 83% of page weight (4.4 MiB of 5.2 MiB)
Info::
Third-party blocking time is low (0 ms)
17%
83%
First-party Third-party
D
HTTP Caching
Action
no-store (uncacheable)
FIX
no-store (uncacheable)
Info::
Cache-Control: no-store prevents all caching
Intentional for dynamic content, but increases server load for every page view.
Got: private, no-cache, no-store, max-age=0, must-revalidate
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

private, no-cache, no-store, max-age=0, must-revalidate

DirectiveValueMeaning
private—Only browser cache, not CDN/proxy
no-cache—Cache but always revalidate first
no-store—Never cache this response
max-age0Cache for 0 seconds
must-revalidate—Must recheck with server after expiry
B
Image Optimization
45 images, 0 KB saveable
REVIEW
45 images, 0 KB saveable
Info::
All images are well-optimized
45 images 1.1 MB
0 oversized -0 KB
20 legacy format
0 missing dimensions CLS risk
C
JS Execution Cost
Action
1501ms total JS execution
REVIEW
1501ms total JS execution
Warning::
Unattributable: 353ms CPU time
Warning::
https://www.pagerduty.com/_next/static/chunks/5686...: 274ms CPU time
Warning::
https://www.pagerduty.com/: 263ms CPU time
Info::
https://www.pagerduty.com/_next/static/chunks/4937...: 169ms CPU time
Info::
https://ob.thisgreencolumn.com/i/313a1c6c53fc549b6...: 129ms CPU time
Info::
Third-party scripts: 670ms (45% of total)

Main Thread Breakdown

Script Evaluation 46% Other 34% Style & Layout 8% Script Parsing & Compilation 6%
ScriptTotalScriptingParse/CompileParty
Unattributable353ms21ms0ms3rd
https://www.pagerduty.com/_next/static/chunks/5686-9fb38a925f588e3e.js274ms55ms2ms1st
https://www.pagerduty.com/263ms35ms40ms1st
https://www.pagerduty.com/_next/static/chunks/4937-6624349af0453281.js169ms161ms5ms1st
https://ob.thisgreencolumn.com/i/313a1c6c53fc549b6cf9213d79f8ac28.js129ms106ms3ms3rd
https://www.pagerduty.com/_next/static/chunks/1ff282bf-9899a0ba0cd01de5.js74ms61ms4ms1st
https://scripts.clarity.ms/0.8.59/clarity.js66ms57ms2ms3rd
https://www.googletagmanager.com/gtag/js?id=DC-1227871664ms54ms7ms3rd
https://cdn.cookielaw.org/scripttemplates/202409.2.0/otBannerSdk.js57ms36ms12ms3rd
https://www.pagerduty.com/_next/static/chunks/3538-10978e3dacff2863.js52ms39ms7ms1st
C
JS Bundles
Action
30 scripts, 288 KB unused
REVIEW
30 scripts, 288 KB unused
Warning::
https://www.pagerduty.com/_next/static/chunks/3538...: 90 KB unused (75%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://cdn.cookielaw.org/scripttemplates/202409.2...: 61 KB unused (54%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtag/js?id=DC-122...: 55 KB unused (42%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://connect.facebook.net/en_US/fbevents.js: 33 KB unused (35%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.pagerduty.com/_next/static/chunks/4638...: 26 KB unused (59%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 288 KB
288 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.pagerduty.com/_next/static/chunks/3538-10978e3dacff2863.js120 KB90 KB (75%)✓1st
https://cdn.cookielaw.org/scripttemplates/202409.2.0/otBannerSdk.js112 KB61 KB (54%)✓3rd
https://www.googletagmanager.com/gtag/js?id=DC-12278716131 KB55 KB (42%)✓3rd
https://connect.facebook.net/en_US/fbevents.js95 KB33 KB (35%)✓3rd
https://www.pagerduty.com/_next/static/chunks/4638-920655eacabd7e48.js44 KB26 KB (59%)✓1st
https://www.pagerduty.com/_next/static/chunks/9279-22d9d462c298a215.js30 KB23 KB (79%)✓1st
https://dev.visualwebsiteoptimizer.com/j.php?a=753563&u=https%3A%2F%2Fwww.pagerduty.com%2F&vn=2.2&ph=1&st=297.6000003814697&x=true13 KB—✓3rd
blob:https://www.pagerduty.com/3b5f805d-e922-4dd7-95ad-b7ae8c97ea9f-0 KB—✓3rd
https://www.pagerduty.com/_next/static/chunks/ac9907b5-ac62fd9a491942d7.js3 KB—✓1st
https://www.pagerduty.com/_next/static/chunks/app/layout-b0c358a71c193fa5.js13 KB—✓1st

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A+
Font Loading
10 fonts (223 KB)
PASS
10 fonts (223 KB)
Info::
10 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

10

223 KB total

Render-blocking

0

of 10

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s 1.5 s FCP 664 ms LCP 1.6 shttps://www.pagerduty.com/_next/static/media/196be43773cacfb1-s.p.woff2196be43773cacfb1-s.p.woff2 https://www.pagerduty.com/_next/static/media/196be43773cacfb1-s.p.woff2 — 22.8 KiB — 0 ms — font-display: swaphttps://www.pagerduty.com/_next/static/media/1dcf2f59595df932-s.p.woff21dcf2f59595df932-s.p.woff2 https://www.pagerduty.com/_next/static/media/1dcf2f59595df932-s.p.woff2 — 22.9 KiB — 0 ms — font-display: swaphttps://www.pagerduty.com/_next/static/media/26ca091aa4cf22dd-s.p.woff226ca091aa4cf22dd-s.p.woff2 https://www.pagerduty.com/_next/static/media/26ca091aa4cf22dd-s.p.woff2 — 21.6 KiB — 0 ms — font-display: swaphttps://www.pagerduty.com/_next/static/media/4bc40f2a9d6ea076-s.p.woff24bc40f2a9d6ea076-s.p.woff2 https://www.pagerduty.com/_next/static/media/4bc40f2a9d6ea076-s.p.woff2 — 22.3 KiB — 0 ms — font-display: swaphttps://www.pagerduty.com/_next/static/media/98c00efcba072cbf-s.p.woff298c00efcba072cbf-s.p.woff2 https://www.pagerduty.com/_next/static/media/98c00efcba072cbf-s.p.woff2 — 22.1 KiB — 0 ms — font-display: swaphttps://www.pagerduty.com/_next/static/media/af6faa570ca87d9d-s.p.woff2af6faa570ca87d9d-s.p.woff2 https://www.pagerduty.com/_next/static/media/af6faa570ca87d9d-s.p.woff2 — 22.2 KiB — 0 ms — font-display: swaphttps://www.pagerduty.com/_next/static/media/df02d7ebb3bb9c24-s.p.woff2df02d7ebb3bb9c24-s.p.woff2 https://www.pagerduty.com/_next/static/media/df02d7ebb3bb9c24-s.p.woff2 — 22.6 KiB — 0 ms — font-display: swaphttps://www.pagerduty.com/_next/static/media/e39d8d8c53f86999-s.p.woff2e39d8d8c53f86999-s.p.woff2 https://www.pagerduty.com/_next/static/media/e39d8d8c53f86999-s.p.woff2 — 21.8 KiB — 0 ms — font-display: swaphttps://www.pagerduty.com/_next/static/media/e901c91968357a19-s.p.woff2e901c91968357a19-s.p.woff2 https://www.pagerduty.com/_next/static/media/e901c91968357a19-s.p.woff2 — 22.5 KiB — 0 ms — font-display: swaphttps://www.pagerduty.com/_next/static/media/f1630277fac7b3a3-s.p.woff2f1630277fac7b3a3-s.p.woff2 https://www.pagerduty.com/_next/static/media/f1630277fac7b3a3-s.p.woff2 — 22.5 KiB — 0 ms — font-display: swap
196be43773cacfb1-s.p.woff2 woff2 swap
Size 23 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
1dcf2f59595df932-s.p.woff2 woff2 swap
Size 23 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
26ca091aa4cf22dd-s.p.woff2 woff2 swap
Size 22 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
4bc40f2a9d6ea076-s.p.woff2 woff2 swap
Size 22 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
98c00efcba072cbf-s.p.woff2 woff2 swap
Size 22 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
af6faa570ca87d9d-s.p.woff2 woff2 swap
Size 22 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
df02d7ebb3bb9c24-s.p.woff2 woff2 swap
Size 23 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
e39d8d8c53f86999-s.p.woff2 woff2 swap
Size 22 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
e901c91968357a19-s.p.woff2 woff2 swap
Size 23 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
f1630277fac7b3a3-s.p.woff2 woff2 swap
Size 22 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Optimization checklist
  • Preload critical fonts (priority=high)
  • Use woff2 format for all fonts
  • Set font-display to swap, optional, or fallback
  • Subset large fonts (≤100 KB each)
A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
No render-blocking resources detected
A+
Resource Hints
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
A+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Cloudflare

Network Waterfall
126 requests over 0ms
INFO

Performance analysis not available for this result.

Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
45% of JavaScript execution is third-party
First-party Third-party 670ms · 313KB · €12/mo
Unattributable
Other
Costly
Execution 353ms
Transfer 0 KB
Monthly Cost €6/mo
ob.thisgreencolumn.com
Other
Optional
Execution 129ms
Transfer 45 KB
Monthly Cost €2/mo
Microsoft Clarity
Session Replay
Optional
Execution 66ms
Transfer 26 KB
Monthly Cost €1/mo
Google Tag Manager
Tag Manager
Optional
Execution 64ms
Transfer 131 KB
Unused 42%
Monthly Cost €1/mo
OneTrust
Consent
Essential
Execution 57ms
Transfer 112 KB
Unused 54%
Monthly Cost €1/mo

These scripts may cost more than they're worth

  • Unattributable adds 353ms and costs ~€6/month

45% of JavaScript execution time comes from third-party scripts.

Why this matters

Third-party scripts (analytics, ads, social, A/B testing) often dominate execution time — every one is a perf-and-privacy tax.

Learn more ▾

Each third-party script is a black box: you don't control when it loads, what it executes, or how much it grows. They often account for a major share of total blocking time on average sites (HTTP Archive's Web Almanac documents the trend). Audit which ones you actually need, defer the rest, and use facade patterns (lite-youtube, lite-vimeo) for embedded media.

Source: web.dev / HTTP Archive Web Almanac

Unattributable takes 353ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

54% of OneTrust's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

Source: web.dev

How third-party costs are calculated

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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