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https://www.bestbuy.com

Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
84
GRADE
B
FIX
3
REVIEW
2
PASS
7
INFO
2

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

Mobile Desktop
73
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
85
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
92
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
83
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.

358 ms

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

418 ms

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

777 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.008

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

358 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.

2.29 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
14
7 PASS 2 REVIEW 3 FIX
D
JS Execution Cost
Action
2455ms total JS execution
FIX
2455ms total JS execution
Warning::
https://www.bestbuy.com/lvOzEqqtES9Y/eI9H-uIfDw/nL...: 978ms CPU time
Warning::
https://www.bestbuy.com/lvOzEqqtES9Y/eI9H-uIfDw/nL...: 693ms CPU time
Warning::
Unattributable: 458ms CPU time
Info::
https://assets.bbystatic.com/analytics-dotcom/anal...: 131ms CPU time
Info::
https://www.bestbuy.com/~assets/bby/_com/cacheable...: 72ms CPU time
Info::
Third-party scripts: 589ms (24% of total)

Main Thread Breakdown

Script Evaluation 73% Other 16% Script Parsing & Compilation 7%
ScriptTotalScriptingParse/CompileParty
https://www.bestbuy.com/lvOzEqqtES9Y/eI9H-uIfDw/nL/Vrb7mrEbiL5b/HiM9MA/AFNAORc/SAGdt?v=4128eac7-76ca-c2a2-44cf-87b0a03a0210978ms793ms79ms1st
https://www.bestbuy.com/lvOzEqqtES9Y/eI9H-uIfDw/nL/p9b7mrEbiL5bGkzE7L/ATs5MA/KxU3V2Q/GUmwB693ms627ms46ms1st
Unattributable458ms157ms0ms3rd
https://assets.bbystatic.com/analytics-dotcom/analyticsInit-f7791796aa580255fd28610903e3089e.js131ms112ms14ms3rd
https://www.bestbuy.com/~assets/bby/_com/cacheable-gvp-66138ea0147dd17ecdc9dc0ac1b86344.min.js72ms51ms19ms1st
https://www.bestbuy.com/akam/13/2ca0c77470ms51ms2ms1st
https://www.bestbuy.com/54ms2ms1ms1st
D
JS Bundles
Action
15 scripts, 308 KB unused
FIX
15 scripts, 308 KB unused
Warning::
https://www.bestbuy.com/~assets/bby/_com/cacheable...: 117 KB unused (74%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://assets.bbystatic.com/analytics-dotcom/anal...: 47 KB unused (55%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.bestbuy.com/lvOzEqqtES9Y/eI9H-uIfDw/nL...: 35 KB unused (21%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.bestbuy.com/lvOzEqqtES9Y/eI9H-uIfDw/nL...: 35 KB unused (21%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.bestbuy.com/lvOzEqqtES9Y/eI9H-uIfDw/nL...: 27 KB unused (18%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 308 KB
308 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.bestbuy.com/~assets/bby/_com/cacheable-gvp-66138ea0147dd17ecdc9dc0ac1b86344.min.js159 KB117 KB (74%)✓1st
https://assets.bbystatic.com/analytics-dotcom/analyticsInit-f7791796aa580255fd28610903e3089e.js87 KB47 KB (55%)✓3rd
https://www.bestbuy.com/lvOzEqqtES9Y/eI9H-uIfDw/nL/p9b7mrEbiL5bGkzE7L/ATs5MA/KxU3V2Q/GUmwB169 KB35 KB (21%)✓1st
https://www.bestbuy.com/lvOzEqqtES9Y/eI9H-uIfDw/nL/p9b7mrEbiL5bGkzE7L/ATs5MA/KxU3V2Q/GUmwB169 KB35 KB (21%)✓1st
https://www.bestbuy.com/lvOzEqqtES9Y/eI9H-uIfDw/nL/Vrb7mrEbiL5b/HiM9MA/AFNAORc/SAGdt?v=4128eac7-76ca-c2a2-44cf-87b0a03a0210149 KB27 KB (18%)✓1st
https://www.bestbuy.com/lvOzEqqtES9Y/eI9H-uIfDw/nL/Vrb7mrEbiL5b/HiM9MA/AFNAORc/SAGdt?v=4128eac7-76ca-c2a2-44cf-87b0a03a02100 KB27 KB (18%)✓1st
https://www.bestbuy.com/~assets/bby/_com/analytics-dotcom/initChildPipeline-ffee00971cdf16cacc57f870e14db909.js37 KB20 KB (56%)✓1st
https://www.bestbuy.com/~assets/bby/_intl/landing_page/js/app.min.js1 KB—✓1st
https://www.bestbuy.com/~assets/bby/_com/legacy-66138ea0147dd17ecdc9dc0ac1b86344.min.js7 KB—✓1st
https://www.bestbuy.com/~assets/bby/_intl/landing_page/js/zepto.min.js10 KB—✓1st

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

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

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

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

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

D
HTTP Caching
Action
no-store (uncacheable)
FIX
no-store (uncacheable)
Info::
Cache-Control: no-store prevents all caching
Intentional for dynamic content, but increases server load for every page view.
Got: max-age=0, no-cache, no-store
Info::
ETag present — enables conditional (304) responses
Info::
Last-Modified header present
Cache-Control

max-age=0, no-cache, no-store

DirectiveValueMeaning
max-age0Cache for 0 seconds
no-cache—Cache but always revalidate first
no-store—Never cache this response
C
Image Optimization
Action
6 images, 0 KB saveable
REVIEW
6 images, 0 KB saveable
Warning::
https://www.bestbuy.com/~assets/bby/_com/header-fo... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.bestbuy.com/~assets/bby/_intl/landing_... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.bestbuy.com/~assets/bby/_intl/landing_... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.bestbuy.com/~assets/bby/_intl/landing_... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
6 images 10 KB
0 oversized -0 KB
4 legacy format
4 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

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

Green Hosting

No green hosting detected

A
Page Weight Budget
900 KB transferred, 73 requests
PASS
900 KB transferred, 73 requests
Info::
Page weighs 3.1 MB (900 KB transferred)
Warning::
JavaScript is 796 KB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 796 KB
Info::
73 HTTP requests
Info::
Estimated 0.18 g CO2 per page load
900 KB / 2.4 MB budget
900 KB transferred
73 requests
0.18 g CO2 per page load
JavaScript 796.4 KiB 88%
Fonts 65.6 KiB 7%
Other 10.7 KiB 1%
Images 9.6 KiB 1%
Other 9.1 KiB 1%
HTML 6.3 KiB 1%
CSS 1.8 KiB 0%
Other 704 B 0%
0 2.4 MB 4.9 MB
Under budget

Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.

Why this matters

JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.

Source: web.dev

A+
Third-Party Impact
11% third-party, 0 ms blocking
PASS
11% third-party, 0 ms blocking
Info::
Third-party code accounts for 11% of page weight (101.6 KiB of 900.2 KiB)
Info::
Third-party blocking time is low (0 ms)
89%
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
3 fonts (66 KB)
PASS
3 fonts (66 KB)
Info::
3 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

3

66 KB total

Render-blocking

0

of 3

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s FCP 358 ms LCP 418 mshttps://www.bestbuy.com/~assets/bby/_com/sc-pattern-library/dist/e4ad7a6cc30f9153dc15124aa8ec616c.woff2e4ad7a6cc30f9153dc15124... https://www.bestbuy.com/~assets/bby/_com/sc-pattern-library/dist/e4ad7a6cc30f9153dc15124aa8ec616c.woff2 — 21.1 KiB — 0 ms — font-display: swaphttps://www.bestbuy.com/~assets/bby/_com/sc-pattern-library/dist/9b64d8057a58697c89b7d537d4f5f809.woff29b64d8057a58697c89b7d53... https://www.bestbuy.com/~assets/bby/_com/sc-pattern-library/dist/9b64d8057a58697c89b7d537d4f5f809.woff2 — 22.3 KiB — 0 ms — font-display: swaphttps://www.bestbuy.com/~assets/bby/_com/sc-pattern-library/dist/5562484cf98053a028aea627e45d4b7c.woff25562484cf98053a028aea62... https://www.bestbuy.com/~assets/bby/_com/sc-pattern-library/dist/5562484cf98053a028aea627e45d4b7c.woff2 — 22.1 KiB — 0 ms — font-display: swap
e4ad7a6cc30f9153dc15124... woff2 swap
Size 21 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
9b64d8057a58697c89b7d53... woff2 swap
Size 22 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
5562484cf98053a028aea62... woff2 swap
Size 22 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Optimization checklist
  • Preload critical fonts (priority=high)
  • Use woff2 format for all fonts
  • Set font-display to swap, optional, or fallback
  • Subset large fonts (≤100 KB each)
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
Network Waterfall
73 requests over 0ms
INFO

Performance analysis not available for this result.

Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
24% of JavaScript execution is third-party
First-party Third-party 589ms · 87KB · $8/mo
Unattributable
Other
Costly
Execution 458ms
Transfer 0 KB
Monthly Cost $6/mo
assets.bbystatic.com
Other
Optional
Execution 131ms
Transfer 87 KB
Unused 55%
Monthly Cost $2/mo

These scripts may cost more than they're worth

  • Unattributable adds 458ms and costs ~$6/month

Unattributable takes 458ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

55% of assets.bbystatic.com'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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