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https://brew.sh

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
99
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
96
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.

1.55 s

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

1.55 s

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.

0.029

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

1.55 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.

1.55 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
D
Third-Party Impact
Action
72% third-party, 0 ms blocking
FIX
72% third-party, 0 ms blocking
Warning::
Third-party code accounts for 72% of page weight (36.7 KiB of 51.3 KiB)
Info::
Third-party blocking time is low (0 ms)
28%
72%
First-party Third-party
B
JS Execution Cost
557ms total JS execution
REVIEW
557ms total JS execution
Warning::
https://brew.sh/: 371ms CPU time
Info::
Unattributable: 136ms CPU time
Info::
https://cdnjs.cloudflare.com/ajax/libs/docsearch-j...: 50ms CPU time
Info::
Third-party scripts: 186ms (33% of total)

Main Thread Breakdown

Style & Layout 40% Other 30% Script Evaluation 13% Rendering 7% Parse HTML & CSS 5% Script Parsing & Compilation 4%
ScriptTotalScriptingParse/CompileParty
https://brew.sh/371ms43ms2ms1st
Unattributable136ms6ms0ms3rd
https://cdnjs.cloudflare.com/ajax/libs/docsearch-js/3.9.0/umd/index.min.js50ms20ms20ms3rd
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Page Weight Budget
51 KB transferred, 8 requests
PASS
51 KB transferred, 8 requests
Info::
Page weighs 192 KB (51 KB transferred)
Info::
8 HTTP requests
Info::
Estimated 0.01 g CO2 per page load
51 KB / 2.4 MB budget
51 KB transferred
8 requests
0.01 g CO2 per page load
JavaScript 33.4 KiB 65%
CSS 7.1 KiB 14%
HTML 5.7 KiB 11%
Images 5.1 KiB 10%
Other 0 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
2 images, 0 KB saveable
PASS
2 images, 0 KB saveable
Info::
All images are well-optimized
2 images 5 KB
0 oversized -0 KB
2 legacy format
0 missing dimensions CLS risk
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
2 scripts, 25 KB unused
PASS
2 scripts, 25 KB unused
Warning::
https://cdnjs.cloudflare.com/ajax/libs/docsearch-j...: 25 KB unused (83%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 25 KB
25 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://cdnjs.cloudflare.com/ajax/libs/docsearch-js/3.9.0/umd/index.min.js31 KB25 KB (83%)✓3rd
https://cdnjs.cloudflare.com/ajax/libs/anchor-js/5.0.0/anchor.min.js3 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

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
1 hints, 0 missing preconnects
PASS
1 hints, 0 missing preconnects
Info::
Page uses 1 resource hint(s)

Current Resource Hints

preconnect
1
preload
—
dns-prefetch
—
prefetch
—

1 resource hints configured

A
Page Weight Inventory
8 resources · 51 KB · 25 KB savings available
PASS
8 resources · 51 KB · 25 KB savings available
Info::
Within 1MB page-weight target
Got: 51 KB
Warning::
3 third-party resources (72% of weight)
8 resources · 51.3 KiB · 3 third-party Within 1MB page-weight target
JavaScript 65% · 33.4 KiB
CSS 14% · 7.1 KiB
Document 11% · 5.7 KiB
Image 10% · 5.1 KiB

~25.1 KiB of savings available

Remove unused JavaScript: 25.1 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+
HTTP Caching
max-age=600 (10 minutes)
PASS
max-age=600 (10 minutes)
Info::
Cache-Control header is set
Got: max-age=600
Info::
Effective TTL: 10 minutes (max-age=600)
Info::
ETag present — enables conditional (304) responses
Info::
Last-Modified header present
Cache-Control

max-age=600

DirectiveValueMeaning
max-age600Cache for 10 minutes
Effective TTL: 600 seconds
Network Waterfall
8 requests over 316ms
INFO
0 ms 500 ms 1.0 s 1.5 s FCP 1.6 s LCP 1.6 shttps://brew.sh// https://brew.sh/ — 200 — 5.7 KiB — 151 ms — h2https://brew.sh/assets/css/style.css/assets/css/style.css https://brew.sh/assets/css/style.css — 200 — 3.8 KiB — 6 ms — h2https://cdnjs.cloudflare.com/ajax/libs/docsearch-css/3.9.0/style.min.csscdnjs.cloudflare.com/ajax/libs/docs... https://cdnjs.cloudflare.com/ajax/libs/docsearch-css/3.9.0/style.min.css — 200 — 3.3 KiB — 26 ms — h3https://brew.sh/assets/img/homebrew.svg/assets/img/homebrew.svg https://brew.sh/assets/img/homebrew.svg — 200 — 1.6 KiB — 9 ms — h2https://brew.sh/assets/img/forkme_right_gray_6d6d6d.svg/assets/img/forkme_right_gray_6d6d6... https://brew.sh/assets/img/forkme_right_gray_6d6d6d.svg — 200 — 3.5 KiB — 14 ms — h2https://cdnjs.cloudflare.com/ajax/libs/anchor-js/5.0.0/anchor.min.jscdnjs.cloudflare.com/ajax/libs/anch... https://cdnjs.cloudflare.com/ajax/libs/anchor-js/5.0.0/anchor.min.js — 200 — 2.8 KiB — 42 ms — h3https://cdnjs.cloudflare.com/ajax/libs/docsearch-js/3.9.0/umd/index.min.jscdnjs.cloudflare.com/ajax/libs/docs... https://cdnjs.cloudflare.com/ajax/libs/docsearch-js/3.9.0/umd/index.min.js — 200 — 30.6 KiB — 42 ms — h3https://brew.sh/assets/img/homebrew.svg/assets/img/homebrew.svg https://brew.sh/assets/img/homebrew.svg — 200 — 0 B — 4 ms — h2
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
33% of JavaScript execution is third-party
First-party Third-party 186ms · 31KB · £1/mo
Unattributable
Other
Optional
Execution 136ms
Transfer 0 KB
Monthly Cost £0/mo
cdnjs
CDN
Optional
Execution 50ms
Transfer 31 KB
Unused 83%
Monthly Cost £0/mo

83% of cdnjs'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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