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Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
91
GRADE
A
FIX
1
REVIEW
3
PASS
11
INFO
2

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

Mobile Desktop
60
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
79
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
92
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.

6.47 s

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

6.47 s

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

2 ms

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

0.046

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

7.63 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.

6.94 s

Page Load Progression

570 ms
1.1 s
1.7 s
2.3 s
2.9 s
3.4 s
4.0 s
4.6 s
Checks
17
11 PASS 3 REVIEW 1 FIX
D
Third-Party Impact
Action
100% third-party, 0 ms blocking
FIX
100% third-party, 0 ms blocking
Warning::
Third-party code accounts for 100% of page weight (301.2 KiB of 301.4 KiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
B
JS Bundles
3 scripts, 108 KB unused
REVIEW
3 scripts, 108 KB unused
Warning::
https://purl.archive.org/static/jquery/jquery.js: 57 KB unused (67%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://purl.archive.org/static/bootstrap/js/boots...: 51 KB unused (75%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://purl.archive.org/static/bootstrap/js/boots...: unminified — 23 KB could be saved
Info::
Total unused JavaScript: 108 KB
108 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://purl.archive.org/static/jquery/jquery.js85 KB57 KB (67%)✓3rd
https://purl.archive.org/static/bootstrap/js/bootstrap.js68 KB51 KB (75%)✗3rd
https://purl.archive.org/static/app.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

B
HTTP Caching
no-cache
REVIEW
no-cache
Info::
Cache-Control header is set
Got: no-cache
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

no-cache

DirectiveValueMeaning
no-cache—Cache but always revalidate first
A+
Page Weight Budget
301 KB transferred, 9 requests
PASS
301 KB transferred, 9 requests
Info::
Page weighs 302 KB (301 KB transferred)
Info::
9 HTTP requests
Info::
Estimated 0.06 g CO2 per page load
301 KB / 2.4 MB budget
301 KB transferred
9 requests
0.06 g CO2 per page load
JavaScript 153.7 KiB 51%
CSS 143.8 KiB 48%
HTML 2.2 KiB 1%
Images 1.1 KiB 0%
Other 580 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
Image Optimization
1 images, 0 KB saveable
PASS
1 images, 0 KB saveable
Warning::
https://purl.archive.org/static/img/logo_IA-sm.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
1 images 1 KB
0 oversized -0 KB
1 legacy format
1 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

A+
JS Execution Cost
306ms total JS execution
PASS
306ms total JS execution
Info::
Unattributable: 148ms CPU time
Info::
https://purl.archive.org/: 85ms CPU time
Info::
https://purl.archive.org/static/jquery/jquery.js: 74ms CPU time
Warning::
Third-party scripts: 306ms (100% of total)

Main Thread Breakdown

Other 49% Script Evaluation 22% Style & Layout 14% Script Parsing & Compilation 7% Parse HTML & CSS 6%
ScriptTotalScriptingParse/CompileParty
Unattributable148ms6ms0ms3rd
https://purl.archive.org/85ms5ms1ms3rd
https://purl.archive.org/static/jquery/jquery.js74ms49ms12ms3rd
A+
Font Loading
No web fonts (system fonts)
PASS
No web fonts (system fonts)
Info::
No web fonts loaded — system fonts are fastest
No web fonts loaded — system fonts are optimal.
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
Page Weight Inventory
9 resources · 301 KB · 108 KB savings available
PASS
9 resources · 301 KB · 108 KB savings available
Info::
Within 1MB page-weight target
Got: 301 KB
Info::
~108 KB of savings available
Warning::
8 third-party resources (100% of weight)
9 resources · 301.4 KiB · 8 third-party Within 1MB page-weight target
JavaScript 51% · 153.7 KiB
CSS 48% · 143.8 KiB
Document 1% · 2.6 KiB
Image 0% · 1.1 KiB
Other 0% · 191 B

~107.7 KiB of savings available

Remove unused JavaScript: 107.7 KiB
A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
Network Waterfall
9 requests over 8559ms
INFO
0 ms 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s 6.0 s 7.0 s 8.0 s FCP 6.5 s LCP 6.5 shttps://purl.org// https://purl.org/ — 307 — 191 B — 532 ms — http/1.1https://purl.archive.org/purl.archive.org/ https://purl.archive.org/ — 200 — 2.2 KiB — 1.0 s — http/1.1https://purl.archive.org/static/bootstrap/css/bootstrap.csspurl.archive.org/static/bootstrap/c... https://purl.archive.org/static/bootstrap/css/bootstrap.css — 200 — 142.9 KiB — 1.5 s — http/1.1https://purl.archive.org/static/style.csspurl.archive.org/static/style.css https://purl.archive.org/static/style.css — 200 — 911 B — 2.0 s — http/1.1https://purl.archive.org/static/img/logo_IA-sm.pngpurl.archive.org/static/img/logo_IA... https://purl.archive.org/static/img/logo_IA-sm.png — 200 — 1.1 KiB — 3.0 s — http/1.1https://purl.archive.org/static/jquery/jquery.jspurl.archive.org/static/jquery/jque... https://purl.archive.org/static/jquery/jquery.js — 200 — 84.6 KiB — 4.3 s — http/1.1https://purl.archive.org/static/bootstrap/js/bootstrap.jspurl.archive.org/static/bootstrap/j... https://purl.archive.org/static/bootstrap/js/bootstrap.js — 200 — 68.4 KiB — 5.3 s — http/1.1https://purl.archive.org/static/app.jspurl.archive.org/static/app.js https://purl.archive.org/static/app.js — 200 — 711 B — 6.0 s — http/1.1https://purl.archive.org/favicon.icopurl.archive.org/favicon.ico https://purl.archive.org/favicon.ico — 404 — 389 B — 988 ms — http/1.1
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
100% of JavaScript execution is third-party
First-party Third-party 306ms · 87KB · $4/mo
Unattributable
Other
Optional
Execution 148ms
Transfer 0 KB
Monthly Cost $2/mo
purl.archive.org
Other
Optional
Execution 85ms
Transfer 2 KB
Monthly Cost $1/mo
purl.archive.org
Other
Optional
Execution 74ms
Transfer 85 KB
Unused 67%
Monthly Cost $1/mo

100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.

Why this matters

When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.

Learn more ▾

Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.

Source: web.dev

67% of purl.archive.org'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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