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Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
73
GRADE
C
FIX
4
REVIEW
3
PASS
5
INFO
2

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

Mobile Desktop
47
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
90
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
69
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.

1.68 s

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

1.90 s

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

4.02 s

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.

4.32 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.

12.57 s

Page Load Progression

1.1 s
2.2 s
3.4 s
4.5 s
5.6 s
6.7 s
7.9 s
9.0 s
Checks
14
5 PASS 3 REVIEW 4 FIX
F
Page Weight Budget
Action
7.4 MB transferred, 350 requests
FIX
7.4 MB transferred, 350 requests
Critical::
Page weighs 25.2 MB (7.4 MB transferred)
Warning::
JavaScript is 6.3 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 6.3 MB
Warning::
350 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 1.5 g CO2 per page load
7.4 MB / 2.4 MB budget
7.4 MB transferred
350 requests
1.5 g CO2 per page load
JavaScript 6.3 MiB 86%
Images 415.0 KiB 6%
HTML 198.3 KiB 3%
Other 188.4 KiB 3%
Other 128.0 KiB 2%
CSS 55.1 KiB 1%
Fonts 33.9 KiB 0%
Other 7.4 KiB 0%
Other 4.6 KiB 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Over 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

Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.

Why this matters

High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.

Source: web.dev

F
JS Execution Cost
Action
11638ms total JS execution
FIX
11638ms total JS execution
Warning::
https://www.sephora.com/resources/87b0af1604642a03...: 5124ms CPU time
Warning::
https://www.sephora.com/: 2101ms CPU time
Warning::
Unattributable: 787ms CPU time
Warning::
https://www.sephora.com/149e9513-01fa-4fb0-aad4-56...: 757ms CPU time
Warning::
https://api.bluecore.com/triggermail.js/sephora.js: 477ms CPU time
Info::
Third-party scripts: 2396ms (21% of total)

Main Thread Breakdown

Script Evaluation 82% Other 7% Script Parsing & Compilation 4% Style & Layout 3%
ScriptTotalScriptingParse/CompileParty
https://www.sephora.com/resources/87b0af1604642a03f9e3b5f9aca755a11630011008b745124ms4754ms30ms1st
https://www.sephora.com/2101ms1608ms14ms1st
Unattributable787ms243ms0ms3rd
https://www.sephora.com/149e9513-01fa-4fb0-aad4-566afd725d1b/2d206a39-8ed7-437e-a3be-862e0f06eea3/ips.js?ak_bmsc-kp=03hwnj2pEEstctt8lQVejBNPxjQ6AgLQ8b3Fp7ED67PRFKsgcMxHHJDJfEmDAxjEckAh6esIMB3ltQyX4ldgmgczDQmFASizgHQdcY7sSXKu3N8cjHTLgqYQ92pSbhSbgEyx5ALPHswtlkvcT8GxySSlDNbrw0mhVXpFT9uFpLNoEp1o9Q&x-kpsdk-v=j-1.2.308&x-kpsdk-im=AAJ2Mv2mEPrHrD2nPANm2Li7DInv9xSFOCHODFDHQSvdBET26KY7R5KNh8NRQDaqZVr3rKR4v_Qi3bHFhX5X4o7mfaw757ms695ms12ms1st
https://api.bluecore.com/triggermail.js/sephora.js477ms376ms11ms3rd
https://www.sephora.com/Cu1NG9QHJy1mN/MV78Hs/yFvckEwo/6b1kVcua/SHl1/WgdV/bCceEThu?v=79b8f2d7-47d5-8f86-a59e-6b2c2f395435324ms307ms12ms1st
https://www.sephora.com/js/ufe/isomorphic/main.bundle.B107CoriginmasterD20260402205602.js295ms161ms125ms1st
https://www.sephora.com/Cu1NG9QHJy1mN/MV78Hs/yFvckEwo/N11kVcuaDOOa4c/c2dx/VTkV/e159LyEB288ms250ms25ms1st
https://assets.adobedtm.com/2f3ab3feab3d/ad943721620d/launch-1aafb95a572f.min.js202ms169ms18ms3rd
https://e309da9b9aaf.cdn4.forter.com/sn/e309da9b9aaf/script.js180ms150ms11ms3rd

Showing top 10 of 24 scripts

F
JS Bundles
Action
127 scripts, 2.9 MB unused
FIX
127 scripts, 2.9 MB unused
Warning::
https://www.sephora.com/js/ufe/isomorphic/main.bun...: 545 KB unused (57%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.sephora.com/js/ufe/isomorphic/commons....: 249 KB unused (80%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.sephora.com/js/ufe/isomorphic/postload...: 216 KB unused (95%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.gstatic.com/recaptcha/releases/kUYUkUl...: 167 KB unused (46%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.gstatic.com/recaptcha/releases/kUYUkUl...: 167 KB unused (46%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 2.9 MB
2940 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.sephora.com/js/ufe/isomorphic/main.bundle.B107CoriginmasterD20260402205602.js964 KB545 KB (57%)✓1st
https://www.sephora.com/js/ufe/isomorphic/commons.chunk.B107CoriginmasterD20260402205602.js313 KB249 KB (80%)✓1st
https://www.sephora.com/js/ufe/isomorphic/postload.chunk.B107CoriginmasterD20260402205602.js227 KB216 KB (95%)✓1st
https://www.gstatic.com/recaptcha/releases/kUYUkUlSyqkjTSMaN2w3RaOh/recaptcha__en.js363 KB167 KB (46%)✓3rd
https://www.gstatic.com/recaptcha/releases/kUYUkUlSyqkjTSMaN2w3RaOh/recaptcha__en.js363 KB167 KB (46%)✓3rd
https://www.gstatic.com/recaptcha/releases/kUYUkUlSyqkjTSMaN2w3RaOh/recaptcha__en.js0 KB167 KB (46%)✓3rd
https://www.gstatic.com/recaptcha/releases/kUYUkUlSyqkjTSMaN2w3RaOh/recaptcha__en.js0 KB167 KB (46%)✓3rd
https://www.sephora.com/js/ufe/isomorphic/priority.chunk.B107CoriginmasterD20260402205602.js165 KB145 KB (88%)✓1st
https://e309da9b9aaf.cdn4.forter.com/sn/e309da9b9aaf/script.js215 KB90 KB (42%)✓3rd
https://api.bluecore.com/triggermail.js/sephora.js102 KB71 KB (71%)✓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

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::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
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
B
Third-Party Impact
50% third-party, 0 ms blocking
REVIEW
50% third-party, 0 ms blocking
Warning::
Third-party code accounts for 50% of page weight (3.7 MiB of 7.4 MiB)
Info::
Third-party blocking time is low (0 ms)
50%
50%
First-party Third-party
B
Image Optimization
74 images, 0 KB saveable
REVIEW
74 images, 0 KB saveable
Warning::
https://www.sephora.com/img/ufe/bi/logo-insider.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
74 images 415 KB
0 oversized -0 KB
41 legacy format
1 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

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

Green Hosting

No green hosting detected

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
1 fonts (34 KB)
PASS
1 fonts (34 KB)
Info::
1 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

1

34 KB total

Render-blocking

0

of 1

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s 1.5 s FCP 1.7 s LCP 1.9 shttps://fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2KFO7CnqEu92Fr1ME7kSn66a... https://fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2 — 33.9 KiB — 0 ms — font-display: swap
KFO7CnqEu92Fr1ME7kSn66a... woff2 swap
Size 34 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
350 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
21% of JavaScript execution is third-party
First-party Third-party 2396ms · 1406KB · $32/mo
Unattributable
Other
Costly
Execution 787ms
Transfer 0 KB
Monthly Cost $10/mo
api.bluecore.com
Other
Costly
Execution 477ms
Transfer 102 KB
Unused 71%
Monthly Cost $6/mo
assets.adobedtm.com
Other
Costly
Execution 202ms
Transfer 107 KB
Unused 26%
Monthly Cost $3/mo
e309da9b9aaf.cdn4.forter.com
Other
Optional
Execution 180ms
Transfer 215 KB
Unused 42%
Monthly Cost $2/mo
Google Tag Manager
Tag Manager
Optional
Execution 100ms
Transfer 178 KB
Unused 36%
Monthly Cost $1/mo
js-cdn.dynatrace.com
Other
Optional
Execution 98ms
Transfer 130 KB
Unused 36%
Monthly Cost $1/mo
cdn.clarip.com
Other
Optional
Execution 95ms
Transfer 4 KB
Monthly Cost $1/mo
Google Tag Manager
Tag Manager
Optional
Execution 91ms
Transfer 147 KB
Unused 38%
Monthly Cost $1/mo
Google Tag Manager
Tag Manager
Optional
Execution 69ms
Transfer 133 KB
Unused 46%
Monthly Cost $1/mo
resources.digital-cloud.medallia.com
Other
Optional
Execution 67ms
Transfer 70 KB
Unused 55%
Monthly Cost $1/mo
analytics.tiktok.com
Other
Optional
Execution 62ms
Transfer 110 KB
Unused 54%
Monthly Cost $1/mo
www.gstatic.com
Other
Optional
Execution 57ms
Transfer 0 KB
Unused 46%
Monthly Cost $1/mo
Google Tag Manager
Tag Manager
Optional
Execution 55ms
Transfer 133 KB
Unused 45%
Monthly Cost $1/mo
Facebook Pixel
Advertising
Optional
Execution 54ms
Transfer 78 KB
Unused 70%
Monthly Cost $1/mo

These scripts may cost more than they're worth

  • Unattributable adds 787ms and costs ~$10/month
  • api.bluecore.com adds 477ms and costs ~$6/month
  • assets.adobedtm.com adds 202ms and costs ~$3/month

Unattributable takes 787ms 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

api.bluecore.com takes 477ms 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

71% of api.bluecore.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

assets.adobedtm.com takes 202ms 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 resources.digital-cloud.medallia.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

54% of analytics.tiktok.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

70% of Facebook Pixel'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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