Skip to content
https://daringfireball.net

Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
92
GRADE
A
FIX
1
REVIEW
1
PASS
11
INFO
1

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

Mobile Desktop
99
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
76
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
73
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.

360 ms

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

888 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.

0.000

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

773 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.

888 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
11 PASS 1 REVIEW 1 FIX
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.

No Cache-Control header

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

C
Image Optimization
Action
11 images, 0 KB saveable
REVIEW
11 images, 0 KB saveable
Warning::
https://daringfireball.net/misc/2026/04/kubrick-19... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://daringfireball.net/misc/2026/04/zed-star-1... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://daringfireball.net/graphics/logos/ is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://daringfireball.net/martini/images/workos.p... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://daringfireball.net/js/images-global/zoom/z... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
11 images 543 KB
0 oversized -0 KB
11 legacy format
5 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

A+
Page Weight Budget
641 KB transferred, 27 requests
PASS
641 KB transferred, 27 requests
Info::
Page weighs 802 KB (641 KB transferred)
Info::
27 HTTP requests
Info::
Estimated 0.13 g CO2 per page load
641 KB / 2.4 MB budget
641 KB transferred
27 requests
0.13 g CO2 per page load
Images 543.4 KiB 85%
HTML 50.1 KiB 8%
JavaScript 34.7 KiB 5%
CSS 9.1 KiB 1%
Other 2.2 KiB 0%
Other 1.1 KiB 0%
0 2.4 MB 4.9 MB
Under budget
A+
Third-Party Impact
2% third-party, 0 ms blocking
PASS
2% third-party, 0 ms blocking
Info::
Third-party code accounts for 2% of page weight (10.7 KiB of 640.6 KiB)
Info::
Third-party blocking time is low (0 ms)
98%
First-party Third-party
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
203ms total JS execution
PASS
203ms total JS execution
Info::
https://daringfireball.net/: 119ms CPU time
Info::
https://daringfireball.net/cdn-cgi/challenge-platf...: 83ms CPU time

Main Thread Breakdown

Script Evaluation 41% Style & Layout 29% Other 23%
ScriptTotalScriptingParse/CompileParty
https://daringfireball.net/119ms17ms1ms1st
https://daringfireball.net/cdn-cgi/challenge-platform/scripts/jsd/main.js83ms80ms1ms1st
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
4 scripts, 0 KB unused
PASS
4 scripts, 0 KB unused
Warning::
https://daringfireball.net/js/js-global/FancyZoom....: unminified — 3 KB could be saved
0 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://daringfireball.net/js/js-global/FancyZoom.js8 KB—✗1st
https://daringfireball.net/js/js-global/FancyZoomHTML.js3 KB—✓1st
https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da177152312451611 KB—✓3rd
https://daringfireball.net/cdn-cgi/challenge-platform/h/b/scripts/jsd/0b8fb825cb67/main.js?13 KB—✓1st
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
27 resources · 641 KB · 0 KB savings available
PASS
27 resources · 641 KB · 0 KB savings available
Info::
Within 1MB page-weight target
Got: 641 KB
Info::
1 third-party resources (2% of weight)
Info::
1 resources over 200KB
27 resources · 640.6 KiB · 1 third-party Within 1MB page-weight target
Image 85% · 544.9 KiB
Document 8% · 50.7 KiB
JavaScript 5% · 34.7 KiB
CSS 1% · 9.1 KiB
Other 0% · 1.3 KiB
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
27 requests over 913ms
INFO
0 ms 200 ms 400 ms 600 ms 800 ms FCP 360 ms LCP 888 mshttps://daringfireball.net// https://daringfireball.net/ — 200 — 50.1 KiB — 263 ms — h2https://daringfireball.net/css/fireball_screen.css?v1.2025-03-12/css/fireball_screen.css?v1.2025-03... https://daringfireball.net/css/fireball_screen.css?v1.2025-03-12 — 200 — 6.4 KiB — 9 ms — h2https://daringfireball.net/css/ie_sucks.php/css/ie_sucks.php https://daringfireball.net/css/ie_sucks.php — 301 — 318 B — 194 ms — h2https://daringfireball.net/js/js-global/FancyZoom.js/js/js-global/FancyZoom.js https://daringfireball.net/js/js-global/FancyZoom.js — 200 — 7.7 KiB — 10 ms — h2https://daringfireball.net/js/js-global/FancyZoomHTML.js/js/js-global/FancyZoomHTML.js https://daringfireball.net/js/js-global/FancyZoomHTML.js — 200 — 3.1 KiB — 12 ms — h2https://daringfireball.net/graphics/logos//graphics/logos/ https://daringfireball.net/graphics/logos/ — 200 — 4.1 KiB — 194 ms — h2https://daringfireball.net/martini/images/workos.png/martini/images/workos.png https://daringfireball.net/martini/images/workos.png — 200 — 62.1 KiB — 14 ms — h2https://daringfireball.net/css/fireball_fontsize.php/css/fireball_fontsize.php https://daringfireball.net/css/fireball_fontsize.php — 301 — 287 B — 190 ms — h2https://daringfireball.net/css/fireball_unicode.css/css/fireball_unicode.css https://daringfireball.net/css/fireball_unicode.css — 200 — 474 B — 9 ms — h2https://daringfireball.net/members/images/2024/classic-976.png/members/images/2024/classic-976.pn... https://daringfireball.net/members/images/2024/classic-976.png — 200 — 297.0 KiB — 19 ms — h2https://daringfireball.net/misc/2026/04/kubrick-1945-subway-flophouse-a.jpeg/misc/2026/04/kubrick-1945-subway-f... https://daringfireball.net/misc/2026/04/kubrick-1945-subway-flophouse-a.jpeg — 200 — 68.7 KiB — 9 ms — h2https://daringfireball.net/misc/2026/04/zed-star-1100.png/misc/2026/04/zed-star-1100.png https://daringfireball.net/misc/2026/04/zed-star-1100.png — 200 — 106.3 KiB — 12 ms — h2https://daringfireball.net/css/ie_sucks/css/ie_sucks https://daringfireball.net/css/ie_sucks — 200 — 423 B — 196 ms — h2https://daringfireball.net/css/fireball_fontsize/css/fireball_fontsize https://daringfireball.net/css/fireball_fontsize — 200 — 454 B — 195 ms — h2https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da1771523124516static.cloudflareinsights.com/beaco... https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da1771523124516 — 200 — 10.7 KiB — 25 ms — h2https://daringfireball.net/css/fireball_print.css?v01/css/fireball_print.css?v01 https://daringfireball.net/css/fireball_print.css?v01 — 200 — 1.3 KiB — 8 ms — h2https://daringfireball.net/cdn-cgi/challenge-platform/scripts/jsd/main.js/cdn-cgi/challenge-platform/scripts... https://daringfireball.net/cdn-cgi/challenge-platform/scripts/jsd/main.js — 302 — 141 B — 18 ms — h2https://daringfireball.net/js/images-global/zoom/zoom-spin-1.png/js/images-global/zoom/zoom-spin-1.... https://daringfireball.net/js/images-global/zoom/zoom-spin-1.png — 200 — 2.2 KiB — 21 ms — h2https://daringfireball.net/js/images-global/zoom/spacer.gif/js/images-global/zoom/spacer.gif https://daringfireball.net/js/images-global/zoom/spacer.gif — 200 — 378 B — 16 ms — h2https://daringfireball.net/js/images-global/zoom/closebox.png/js/images-global/zoom/closebox.png https://daringfireball.net/js/images-global/zoom/closebox.png — 200 — 1008 B — 22 ms — h2https://daringfireball.net/js/images-global/zoom/zoom-caption-l.png/js/images-global/zoom/zoom-caption... https://daringfireball.net/js/images-global/zoom/zoom-caption-l.png — 200 — 664 B — 13 ms — h2https://daringfireball.net/js/images-global/zoom/zoom-caption-r.png/js/images-global/zoom/zoom-caption... https://daringfireball.net/js/images-global/zoom/zoom-caption-r.png — 200 — 592 B — 17 ms — h2https://daringfireball.net/js/images-global/zoom/zoom-caption-fill.png/js/images-global/zoom/zoom-caption... https://daringfireball.net/js/images-global/zoom/zoom-caption-fill.png — 200 — 440 B — 15 ms — h2https://daringfireball.net/cdn-cgi/challenge-platform/h/b/scripts/jsd/0b8fb825cb67/main.js?/cdn-cgi/challenge-platform/h/b/scr... https://daringfireball.net/cdn-cgi/challenge-platform/h/b/scripts/jsd/0b8fb825cb67/main.js? — 200 — 13.2 KiB — 15 ms — h2https://daringfireball.net/cdn-cgi/rum?/cdn-cgi/rum? https://daringfireball.net/cdn-cgi/rum? — 204 — 369 B — 20 ms — h2https://daringfireball.net/graphics/favicon.ico?v=005/graphics/favicon.ico?v=005 https://daringfireball.net/graphics/favicon.ico?v=005 — 200 — 1.5 KiB — 11 ms — h2https://daringfireball.net/cdn-cgi/challenge-platform/h/b/jsd/oneshot/0b8fb825cb67/0.6688030970413026:1776809557:O7rLN3nqnRpqq1ETlvF4OHvbb1xtfdyTnSr74k0fOwE/9effdfacfbd7c02b/cdn-cgi/challenge-platform/h/b/jsd... https://daringfireball.net/cdn-cgi/challenge-platform/h/b/jsd/oneshot/0b8fb825cb67/0.6688030970413026:1776809557:O7rLN3nqnRpqq1ETlvF4OHvbb1xtfdyTnSr74k0fOwE/9effdfacfbd7c02b — 200 — 783 B — 10 ms — h2
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.

Send Feedback