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https://random.org

Performance

· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
93
GRADE
A
FIX
2
REVIEW
1
PASS
10
INFO
2

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.
70
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
96
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
100
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.

804 ms

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

804 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.

804 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.

804 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
15
10 PASS 1 REVIEW 2 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 (86.7 KiB of 86.9 KiB)
Info::
Third-party blocking time is low (0 ms)
100%
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.

No Cache-Control header

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

B
Image Optimization
5 images, 0 KB saveable
REVIEW
5 images, 0 KB saveable
Info::
All images are well-optimized
5 images 30 KB
0 oversized -0 KB
5 legacy format
0 missing dimensions CLS risk
A+
Page Weight Budget
87 KB transferred, 18 requests
PASS
87 KB transferred, 18 requests
Info::
Page weighs 234 KB (87 KB transferred)
Info::
18 HTTP requests
Info::
Estimated 0.02 g CO2 per page load
87 KB / 2.4 MB budget
87 KB transferred
18 requests
0.02 g CO2 per page load
JavaScript 43.1 KiB 50%
Images 29.8 KiB 34%
HTML 10.7 KiB 12%
CSS 2.0 KiB 2%
Other 998 B 1%
Other 212 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
56ms total JS execution
PASS
56ms total JS execution
Info::
https://static.random.org/lib/jquery-3.4.1/jquery-...: 56ms CPU time
Warning::
Third-party scripts: 56ms (100% of total)

Main Thread Breakdown

Other 37% Script Evaluation 35% Style & Layout 17% Script Parsing & Compilation 4% Parse HTML & CSS 3%
ScriptTotalScriptingParse/CompileParty
https://static.random.org/lib/jquery-3.4.1/jquery-3.4.1.min.js56ms20ms2ms3rd
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
5 scripts, 0 KB unused
PASS
5 scripts, 0 KB unused
0 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.random.org/js/random.js2 KB—✓3rd
https://static.random.org/lib/jquery-3.4.1/jquery-3.4.1.min.js30 KB—✓3rd
https://www.random.org/js/simpledropdown.jquery.js0 KB—✓3rd
https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da177152312451611 KB—✓3rd
https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da17715231245160 KB—✓3rd
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
18 resources · 87 KB · 0 KB savings available
PASS
18 resources · 87 KB · 0 KB savings available
Info::
Within 1MB page-weight target
Got: 87 KB
Warning::
17 third-party resources (100% of weight)
18 resources · 86.9 KiB · 17 third-party Within 1MB page-weight target
JavaScript 50% · 43.1 KiB
Image 35% · 30.3 KiB
Document 13% · 11.0 KiB
CSS 2% · 2.0 KiB
Other 0% · 398 B
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
18 requests over 394ms
INFO
0 ms 200 ms 400 ms 600 ms 800 ms FCP 804 ms LCP 804 mshttps://random.org// https://random.org/ — 301 — 186 B — 67 ms — h2https://www.random.org/www.random.org/ https://www.random.org/ — 200 — 6.9 KiB — 60 ms — h2https://www.random.org/css/style.csswww.random.org/css/style.css https://www.random.org/css/style.css — 200 — 2.0 KiB — 28 ms — h2https://www.random.org/js/random.jswww.random.org/js/random.js https://www.random.org/js/random.js — 200 — 2.0 KiB — 29 ms — h2https://static.random.org/lib/jquery-3.4.1/jquery-3.4.1.min.jsstatic.random.org/lib/jquery-3.4.1/... https://static.random.org/lib/jquery-3.4.1/jquery-3.4.1.min.js — 200 — 30.1 KiB — 96 ms — h2https://www.random.org/js/simpledropdown.jquery.jswww.random.org/js/simpledropdown.jq... https://www.random.org/js/simpledropdown.jquery.js — 200 — 258 B — 29 ms — h2https://www.random.org/graphics/nuvola/learn.pngwww.random.org/graphics/nuvola/lear... https://www.random.org/graphics/nuvola/learn.png — 200 — 11.0 KiB — 27 ms — h2https://www.random.org/graphics/nuvola/graph.pngwww.random.org/graphics/nuvola/grap... https://www.random.org/graphics/nuvola/graph.png — 200 — 7.9 KiB — 27 ms — h2https://www.random.org/graphics/nuvola/help.gifwww.random.org/graphics/nuvola/help... https://www.random.org/graphics/nuvola/help.gif — 200 — 5.8 KiB — 27 ms — h2https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da1771523124516static.cloudflareinsights.com/beaco... https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da1771523124516 — 200 — 10.7 KiB — 67 ms — h2https://www.random.org/graphics/tab_rounded.gifwww.random.org/graphics/tab_rounded... https://www.random.org/graphics/tab_rounded.gif — 200 — 213 B — 28 ms — h2https://www.random.org/widgets/integers/iframe.php?title=True+Random+Number+Generator&buttontxt=Generate&width=160&height=230&border=on&bgcolor=%23FFFFFF&txtcolor=%23777777&altbgcolor=%23CCCCFFA&alttxtcolor=%23000000&defaultmin=1&defaultmax=100&fixed=offwww.random.org/widgets/integers/ifr... https://www.random.org/widgets/integers/iframe.php?title=True+Random+Number+Generator&buttontxt=Generate&width=160&height=230&border=on&bgcolor=%23FFFFFF&txtcolor=%23777777&altbgcolor=%23CCCCFFA&alttxtcolor=%23000000&defaultmin=1&defaultmax=100&fixed=off — 301 — 305 B — 44 ms — h2https://www.random.org/graphics/rdo-logo-475x70.pngwww.random.org/graphics/rdo-logo-47... https://www.random.org/graphics/rdo-logo-475x70.png — 200 — 5.0 KiB — 29 ms — h2https://www.random.org/widgets/integers/iframe?title=True+Random+Number+Generator&buttontxt=Generate&width=160&height=230&border=on&bgcolor=%23FFFFFF&txtcolor=%23777777&altbgcolor=%23CCCCFFA&alttxtcolor=%23000000&defaultmin=1&defaultmax=100&fixed=offwww.random.org/widgets/integers/ifr... https://www.random.org/widgets/integers/iframe?title=True+Random+Number+Generator&buttontxt=Generate&width=160&height=230&border=on&bgcolor=%23FFFFFF&txtcolor=%23777777&altbgcolor=%23CCCCFFA&alttxtcolor=%23000000&defaultmin=1&defaultmax=100&fixed=off — 200 — 3.8 KiB — 37 ms — h2https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da1771523124516static.cloudflareinsights.com/beaco... https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da1771523124516 — 200 — 0 B — 0 ms — h2https://www.random.org/cdn-cgi/rum?www.random.org/cdn-cgi/rum? https://www.random.org/cdn-cgi/rum? — 204 — 38 B — 23 ms — h2https://www.random.org/cdn-cgi/rum?www.random.org/cdn-cgi/rum? https://www.random.org/cdn-cgi/rum? — 204 — 174 B — 21 ms — h2https://www.random.org/favicon.icowww.random.org/favicon.ico https://www.random.org/favicon.ico — 200 — 507 B — 27 ms — h2
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 56ms · 30KB · €1/mo
static.random.org
Other
Optional
Execution 56ms
Transfer 30 KB
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

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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