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Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
87
GRADE
B
FIX
2
REVIEW
3
PASS
7
INFO
2

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

Mobile Desktop
74
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
80
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
100
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
92
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.

2.38 s

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

2.38 s

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

0 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.

2.38 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.

2.38 s

Page Load Progression

375 ms
750 ms
1.1 s
1.5 s
1.9 s
2.2 s
2.6 s
3.0 s
Checks
14
7 PASS 3 REVIEW 2 FIX
D
Third-Party Impact
Action
99% third-party, 0 ms blocking
FIX
99% third-party, 0 ms blocking
Warning::
Third-party code accounts for 99% of page weight (414.0 KiB of 417.4 KiB)
Info::
Third-party blocking time is low (0 ms)
99%
First-party Third-party
F
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.
Info::
Last-Modified header present

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

C
Image Optimization
Action
18 images, 0 KB saveable
REVIEW
18 images, 0 KB saveable
Warning::
https://cdn.perl.org/perlweb/images/icons/ic_downl... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn.perl.org/perlweb/images/icons/creative... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn.perl.org/perlweb/images/icons/ic_heade... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn.perl.org/perlweb/images/icons/ic_heade... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn.perl.org/perlweb/images/icons/ic_heade... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn.perl.org/perlweb/images/logo.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn.perl.org/perlweb/images/icons/ic_heade... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn.perl.org/perlweb/images/icons/ic_heade... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn.perl.org/perlweb/images/icons/header_c... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn.perl.org/perlweb/images/icons/ic_heade... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
18 images 43 KB
0 oversized -0 KB
18 legacy format
10 missing dimensions CLS risk

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

B
JS Bundles
6 scripts, 124 KB unused
REVIEW
6 scripts, 124 KB unused
Warning::
https://www.googletagmanager.com/gtag/js?id=G-H3V4...: 62 KB unused (41%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtag/js?id=UA-505...: 62 KB unused (53%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 124 KB
124 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.googletagmanager.com/gtag/js?id=G-H3V42907P1&cx=c&gtm=4e6460h1153 KB62 KB (41%)✓3rd
https://www.googletagmanager.com/gtag/js?id=UA-50555-1116 KB62 KB (53%)✓3rd
https://cdn.perl.org/js/script.file-downloads.outbound-links.js2 KB—✓3rd
https://cdn.perl.org/perlweb/js/perlweb_bootstrap.min.js23 KB—✓3rd
https://www.google-analytics.com/analytics.js21 KB—✓3rd
https://www.google-analytics.com/plugins/ua/linkid.js1 KB—✓3rd

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

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Page Weight Budget
417 KB transferred, 34 requests
PASS
417 KB transferred, 34 requests
Info::
Page weighs 1.1 MB (417 KB transferred)
Info::
34 HTTP requests
Info::
Estimated 0.09 g CO2 per page load
417 KB / 2.4 MB budget
417 KB transferred
34 requests
0.09 g CO2 per page load
JavaScript 316.0 KiB 76%
Images 42.7 KiB 10%
Fonts 41.2 KiB 10%
CSS 11.9 KiB 3%
HTML 3.4 KiB 1%
Other 902 B 0%
Other 809 B 0%
Other 547 B 0%
0 2.4 MB 4.9 MB
Under budget
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+
JS Execution Cost
340ms total JS execution
PASS
340ms total JS execution
Info::
Unattributable: 134ms CPU time
Info::
https://www.perl.org/: 118ms CPU time
Info::
https://www.googletagmanager.com/gtag/js?id=G-H3V4...: 87ms CPU time
Warning::
Third-party scripts: 221ms (65% of total)

Main Thread Breakdown

Script Evaluation 44% Other 27% Style & Layout 16% Script Parsing & Compilation 9%
ScriptTotalScriptingParse/CompileParty
Unattributable134ms32ms0ms3rd
https://www.perl.org/118ms26ms1ms1st
https://www.googletagmanager.com/gtag/js?id=G-H3V42907P1&cx=c&gtm=4e6460h187ms65ms21ms3rd
A+
Font Loading
3 fonts (41 KB)
PASS
3 fonts (41 KB)
Info::
3 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

3

41 KB total

Render-blocking

0

of 3

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 2.0 s 2.5 s FCP 2.4 s LCP 2.4 shttps://fonts.gstatic.com/s/lato/v25/S6uyw4BMUTPHjx4wXiWtFCc.woff2S6uyw4BMUTPHjx4wXiWtFCc... https://fonts.gstatic.com/s/lato/v25/S6uyw4BMUTPHjx4wXiWtFCc.woff2 — 13.7 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/lato/v25/S6u9w4BMUTPHh7USSwiPGQ3q5d0.woff2S6u9w4BMUTPHh7USSwiPGQ3... https://fonts.gstatic.com/s/lato/v25/S6u9w4BMUTPHh7USSwiPGQ3q5d0.woff2 — 13.6 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/lato/v25/S6u9w4BMUTPHh6UVSwiPGQ3q5d0.woff2S6u9w4BMUTPHh6UVSwiPGQ3... https://fonts.gstatic.com/s/lato/v25/S6u9w4BMUTPHh6UVSwiPGQ3q5d0.woff2 — 13.9 KiB — 0 ms — font-display: swap
S6uyw4BMUTPHjx4wXiWtFCc... woff2 swap
Size 14 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
S6u9w4BMUTPHh7USSwiPGQ3... woff2 swap
Size 14 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
S6u9w4BMUTPHh6UVSwiPGQ3... woff2 swap
Size 14 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
Network Waterfall
34 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
65% of JavaScript execution is third-party
First-party Third-party 221ms · 153KB · $3/mo
Unattributable
Other
Optional
Execution 134ms
Transfer 0 KB
Monthly Cost $2/mo
Google Tag Manager
Tag Manager
Optional
Execution 87ms
Transfer 153 KB
Unused 41%
Monthly Cost $1/mo

65% 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

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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