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https://xkcd.com

Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
92
GRADE
A
FIX
1
REVIEW
2
PASS
10
INFO
1

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

Mobile Desktop
86
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
72
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.

248 ms

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

731 ms

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.

0.265

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

248 ms

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

731 ms

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
10 PASS 2 REVIEW 1 FIX
D
Third-Party Impact
Action
95% third-party, 0 ms blocking
FIX
95% third-party, 0 ms blocking
Warning::
Third-party code accounts for 95% of page weight (333.9 KiB of 350.6 KiB)
Info::
Third-party blocking time is low (0 ms)
95%
First-party Third-party
B
Image Optimization
4 images, 0 KB saveable
REVIEW
4 images, 0 KB saveable
Warning::
https://imgs.xkcd.com/comics/types_of_board_game.p... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
4 images 345 KB
0 oversized -0 KB
4 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

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

Green Hosting

No green hosting detected

A+
Page Weight Budget
351 KB transferred, 7 requests
PASS
351 KB transferred, 7 requests
Info::
Page weighs 356 KB (351 KB transferred)
Info::
7 HTTP requests
Info::
Estimated 0.07 g CO2 per page load
351 KB / 2.4 MB budget
351 KB transferred
7 requests
0.07 g CO2 per page load
Images 345.1 KiB 98%
HTML 2.7 KiB 1%
CSS 1.6 KiB 0%
Other 1.2 KiB 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
No JS execution data
PASS
No JS execution data
Info::
No significant JS execution detected

Main Thread Breakdown

Other 48% Style & Layout 39% Script Evaluation 5% Rendering 4% Parse HTML & CSS 3%
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+
JS Bundles
No JavaScript
PASS
No JavaScript
Info::
No JavaScript bundles
No JavaScript files loaded.
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
7 resources · 351 KB · 0 KB savings available
PASS
7 resources · 351 KB · 0 KB savings available
Info::
Within 1MB page-weight target
Got: 351 KB
Warning::
3 third-party resources (95% of weight)
Info::
1 resources over 200KB
7 resources · 350.6 KiB · 3 third-party Within 1MB page-weight target
Image 99% · 346.3 KiB
Document 1% · 2.7 KiB
CSS 0% · 1.6 KiB
A+
HTTP Caching
max-age=300 (5 minutes)
PASS
max-age=300 (5 minutes)
Info::
Cache-Control header is set
Got: max-age=300
Info::
Effective TTL: 5 minutes (max-age=300)
Info::
ETag present — enables conditional (304) responses
Cache-Control

max-age=300

DirectiveValueMeaning
max-age300Cache for 5 minutes
Effective TTL: 300 seconds
Network Waterfall
7 requests over 76ms
INFO
0 ms 200 ms 400 ms 600 ms FCP 248 ms LCP 731 mshttps://xkcd.com// https://xkcd.com/ — 200 — 2.7 KiB — 12 ms — http/1.1https://xkcd.com/s/7d94e0.css/s/7d94e0.css https://xkcd.com/s/7d94e0.css — 200 — 1.6 KiB — 6 ms — http/1.1https://xkcd.com/s/0b7742.png/s/0b7742.png https://xkcd.com/s/0b7742.png — 200 — 11.2 KiB — 5 ms — http/1.1https://imgs.xkcd.com/comics/types_of_board_game.pngimgs.xkcd.com/comics/types_of_board... https://imgs.xkcd.com/comics/types_of_board_game.png — 200 — 285.1 KiB — 40 ms — http/1.1https://imgs.xkcd.com/s/a899e84.jpgimgs.xkcd.com/s/a899e84.jpg https://imgs.xkcd.com/s/a899e84.jpg — 200 — 21.3 KiB — 20 ms — http/1.1https://imgs.xkcd.com/s/temperature.pngimgs.xkcd.com/s/temperature.png https://imgs.xkcd.com/s/temperature.png — 200 — 27.4 KiB — 15 ms — http/1.1https://xkcd.com/s/919f27.ico/s/919f27.ico https://xkcd.com/s/919f27.ico — 200 — 1.2 KiB — 6 ms — http/1.1
HTML JavaScript CSS Images Fonts XHR/Fetch Other
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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