Skip to content
https://daringfireball.net

Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
92
GRADE
A
FIX
1
REVIEW
2
PASS
12
INFO
2

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

Mobile Desktop
80
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
81
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.

1.38 s

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

4.54 s

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

134 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.

4.37 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.

4.54 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
17
12 PASS 2 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/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/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/js/images-global/zoom/z... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
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.
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

C
JS Execution Cost
Action
1113ms total JS execution
REVIEW
1113ms total JS execution
Warning::
https://daringfireball.net/: 510ms CPU time
Warning::
https://daringfireball.net/cdn-cgi/challenge-platf...: 359ms CPU time
Info::
Unattributable: 183ms CPU time
Info::
https://static.cloudflareinsights.com/beacon.min.j...: 62ms CPU time
Info::
Third-party scripts: 245ms (22% of total)

Main Thread Breakdown

Script Evaluation 41% Style & Layout 30% Other 22%
ScriptTotalScriptingParse/CompileParty
https://daringfireball.net/510ms69ms3ms1st
https://daringfireball.net/cdn-cgi/challenge-platform/scripts/jsd/main.js359ms346ms4ms1st
Unattributable183ms6ms0ms3rd
https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da177152312451662ms36ms4ms3rd
A+
Page Weight Budget
640 KB transferred, 27 requests
PASS
640 KB transferred, 27 requests
Info::
Page weighs 801 KB (640 KB transferred)
Info::
27 HTTP requests
Info::
Estimated 0.13 g CO2 per page load
640 KB / 2.4 MB budget
640 KB transferred
27 requests
0.13 g CO2 per page load
Images 543.3 KiB 85%
HTML 50.2 KiB 8%
JavaScript 34.5 KiB 5%
CSS 9.2 KiB 1%
Other 2.2 KiB 0%
Other 960 B 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 640.3 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+
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 · 640 KB · 0 KB savings available
PASS
27 resources · 640 KB · 0 KB savings available
Info::
Within 1MB page-weight target
Got: 640 KB
Info::
1 third-party resources (2% of weight)
Info::
1 resources over 200KB
27 resources · 640.3 KiB · 1 third-party Within 1MB page-weight target
Image 85% · 544.8 KiB
Document 8% · 50.8 KiB
JavaScript 5% · 34.5 KiB
CSS 1% · 9.2 KiB
Other 0% · 1.1 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
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 924ms
INFO
0 ms 1.0 s 2.0 s 3.0 s 4.0 s FCP 1.4 s LCP 4.5 shttps://daringfireball.net// https://daringfireball.net/ — 200 — 50.2 KiB — 251 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 — 15 ms — h2https://daringfireball.net/css/ie_sucks.php/css/ie_sucks.php https://daringfireball.net/css/ie_sucks.php — 301 — 318 B — 190 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 — 16 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 — 19 ms — h2https://daringfireball.net/graphics/logos//graphics/logos/ https://daringfireball.net/graphics/logos/ — 200 — 4.1 KiB — 570 ms — h2https://daringfireball.net/martini/images/workos.png/martini/images/workos.png https://daringfireball.net/martini/images/workos.png — 200 — 62.1 KiB — 21 ms — h2https://daringfireball.net/css/fireball_fontsize.php/css/fireball_fontsize.php https://daringfireball.net/css/fireball_fontsize.php — 301 — 292 B — 194 ms — h2https://daringfireball.net/css/fireball_unicode.css/css/fireball_unicode.css https://daringfireball.net/css/fireball_unicode.css — 200 — 598 B — 26 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 — 296.9 KiB — 22 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 — 13 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 — 14 ms — h2https://daringfireball.net/css/ie_sucks/css/ie_sucks https://daringfireball.net/css/ie_sucks — 200 — 411 B — 206 ms — h2https://daringfireball.net/css/fireball_fontsize/css/fireball_fontsize https://daringfireball.net/css/fireball_fontsize — 200 — 395 B — 191 ms — h2https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da1771523124516static.cloudflareinsights.com/beaco... https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da1771523124516 — 200 — 10.7 KiB — 36 ms — h2https://daringfireball.net/css/fireball_print.css?v01/css/fireball_print.css?v01 https://daringfireball.net/css/fireball_print.css?v01 — 200 — 1.4 KiB — 12 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 — 5 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 — 13.0 KiB — 10 ms — h2https://daringfireball.net/cdn-cgi/challenge-platform/h/b/jsd/oneshot/0b8fb825cb67/0.6688030970413026:1776809557:O7rLN3nqnRpqq1ETlvF4OHvbb1xtfdyTnSr74k0fOwE/9effdf36dc143289/cdn-cgi/challenge-platform/h/b/jsd... https://daringfireball.net/cdn-cgi/challenge-platform/h/b/jsd/oneshot/0b8fb825cb67/0.6688030970413026:1776809557:O7rLN3nqnRpqq1ETlvF4OHvbb1xtfdyTnSr74k0fOwE/9effdf36dc143289 — 200 — 589 B — 15 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 — 20 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 — 373 B — 22 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 — 953 B — 17 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 — 700 B — 14 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 — 641 B — 12 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 — 445 B — 17 ms — h2https://daringfireball.net/cdn-cgi/rum?/cdn-cgi/rum? https://daringfireball.net/cdn-cgi/rum? — 204 — 371 B — 5 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 — 15 ms — h2
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
22% of JavaScript execution is third-party
First-party Third-party 245ms · 11KB · €3/mo
Unattributable
Other
Optional
Execution 183ms
Transfer 0 KB
Monthly Cost €2/mo
static.cloudflareinsights.com
Other
Optional
Execution 62ms
Transfer 11 KB
Monthly Cost €1/mo

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.

Send Feedback