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https://skims.com

Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
73
GRADE
C
FIX
5
REVIEW
1
PASS
8
INFO
2

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

Mobile Desktop
30
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
88
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.
61
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.

5.14 s

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

8.88 s

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

2.22 s

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

0.017

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

8.00 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.

20.11 s

Page Load Progression

396 ms
793 ms
1.2 s
1.6 s
2.0 s
2.4 s
2.8 s
3.2 s
Checks
16
8 PASS 1 REVIEW 5 FIX
F
Page Weight Budget
Action
2.9 MB transferred, 150 requests
FIX
2.9 MB transferred, 150 requests
Warning::
Page weighs 7.6 MB (2.9 MB transferred)
Warning::
JavaScript is 1.3 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.3 MB
Warning::
Images are 1.1 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 1.1 MB
Warning::
150 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 0.60 g CO2 per page load
2.9 MB / 2.4 MB budget
2.9 MB transferred
150 requests
0.60 g CO2 per page load
JavaScript 1.3 MiB 46%
Images 1.1 MiB 39%
Other 132.9 KiB 5%
Fonts 85.7 KiB 3%
HTML 76.9 KiB 3%
Other 57.7 KiB 2%
Other 42.7 KiB 1%
CSS 30.0 KiB 1%
Other 5.2 KiB 0%
Other 2.2 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

Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.

Why this matters

Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.

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

D
Third-Party Impact
Action
94% third-party, 0 ms blocking
FIX
94% third-party, 0 ms blocking
Warning::
Third-party code accounts for 94% of page weight (2.7 MiB of 2.9 MiB)
Info::
Third-party blocking time is low (0 ms)
94%
First-party Third-party
F
JS Execution Cost
Action
13725ms total JS execution
FIX
13725ms total JS execution
Warning::
https://cdn.shopify.com/oxygen-v2/26957/18156/3748...: 4296ms CPU time
Warning::
https://cdn.shopify.com/oxygen-v2/26957/18156/3748...: 4110ms CPU time
Warning::
Unattributable: 1613ms CPU time
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-N9X...: 873ms CPU time
Warning::
https://skims.com/en-br: 737ms CPU time
Warning::
Third-party scripts: 12988ms (95% of total)

Main Thread Breakdown

Script Evaluation 72% Other 15% Style & Layout 5% Script Parsing & Compilation 3%
ScriptTotalScriptingParse/CompileParty
https://cdn.shopify.com/oxygen-v2/26957/18156/37484/3315550/assets/index-DyRoOIe0.js4296ms3780ms1ms3rd
https://cdn.shopify.com/oxygen-v2/26957/18156/37484/3315550/assets/root-gDyipPt0.js4110ms3396ms9ms3rd
Unattributable1613ms328ms0ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-N9XLT5N873ms727ms114ms3rd
https://skims.com/en-br737ms26ms47ms1st
https://9236cacba5af.cdn4.forter.com/sn/9236cacba5af/script.js686ms605ms60ms3rd
https://st.dynamicyield.com/st?sec=8777639&ref=&scriptVersion=2.83.0&inHead=true&id=2359886468510780859&jsession=pp4i06rdxambe51og6au1bph3g34whh8&isSesNew=false&landingUrl=&dyid_server=2359886468510780859&ctx=%7B%22type%22%3A%22HOMEPAGE%22%2C%22data%22%3A%5B%5D%2C%22lng%22%3A%22en_BR%22%7D330ms300ms12ms3rd
https://cdn.cookielaw.org/scripttemplates/202306.1.0/otBannerSdk.js326ms207ms56ms3rd
https://cdn.dynamicyield.com/api/8777639/api_dynamic.js324ms252ms67ms3rd
https://web-sdk-cdn.singular.net/singular-sdk/latest/singular-sdk.js116ms83ms21ms3rd

Showing top 10 of 14 scripts

F
JS Bundles
Action
34 scripts, 502 KB unused
FIX
34 scripts, 502 KB unused
Warning::
https://cdn.shopify.com/oxygen-v2/26957/18156/3748...: 250 KB unused (60%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://9236cacba5af.cdn4.forter.com/sn/9236cacba5...: 86 KB unused (40%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-N9X...: 59 KB unused (29%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://cdn.dynamicyield.com/api/8777639/api_stati...: 57 KB unused (55%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://cdn.cookielaw.org/scripttemplates/202306.1...: 50 KB unused (52%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 502 KB
502 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://cdn.shopify.com/oxygen-v2/26957/18156/37484/3315550/assets/root-gDyipPt0.js419 KB250 KB (60%)✓3rd
https://9236cacba5af.cdn4.forter.com/sn/9236cacba5af/script.js214 KB86 KB (40%)✓3rd
https://www.googletagmanager.com/gtm.js?id=GTM-N9XLT5N200 KB59 KB (29%)✓3rd
https://cdn.dynamicyield.com/api/8777639/api_static.js104 KB57 KB (55%)✓3rd
https://cdn.cookielaw.org/scripttemplates/202306.1.0/otBannerSdk.js98 KB50 KB (52%)✓3rd
https://sdk-api-v1.singular.net/api/v1/event?current_device_time=1775635901&event_id=fb7149c7-fc19-48fc-8993-3ac5057404db&conversion_event=true&k=SDID&a=skims_body_inc_f0f5bbdc&p=Web&i=https%3A%2F%2Fskims.com&screen_height=823&screen_width=412&sdk=WebSDK-v1.4.10&singular_instance_id=c1e9bd5d-eb81-465e-badc-cf85eb77ec80&sdid=6f6ddb5d-5158-4363-9da2-782c66654fb1&storage_type=local&timezone=GMT%2B0000&touchpoint_timestamp=1775635901&u=6f6ddb5d-5158-4363-9da2-782c66654fb1&n=__PAGE_VISIT__&is_revenue_event=false&first=true&is_after_conversion_event=false&s=04128ee1-c3c9-4953-a679-e406fd24eee0&web_page_url=https%3A%2F%2Fskims.com%2Fen-br&is_first_visit=true&is_page_refreshed=false&sdid_persist_mode=auto&is_first_page_visit_in_session=true&ecid=6f6ddb5d-5158-4363-9da2-782c66654fb1&os=Android&lag=0&h=899ddbd3cd93d8dd6d88b85c3b9fa29b7d093aad0 KB—✓3rd
https://crossborder-integration.global-e.com/resources/js/app?shop=skimsbody.myshopify.com23 KB—✗3rd
https://cdn.shopify.com/oxygen-v2/26957/18156/37484/3315550/assets/root-Bk7lSGz8.js1 KB—✓3rd
https://cdn.shopify.com/oxygen-v2/26957/18156/37484/3315550/assets/entry.client-kF13gapv.js3 KB—✓3rd
https://cdn.shopify.com/oxygen-v2/26957/18156/37484/3315550/assets/route-Dhrgbq7W.js1 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

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

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
55 images, 0 KB saveable
REVIEW
55 images, 0 KB saveable
Warning::
https://skims-sanity.imgix.net/images/hfqi0zm0/pro... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://skims-sanity.imgix.net/images/hfqi0zm0/pro... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn.sanity.io/images/hfqi0zm0/production/c... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://skims-sanity.imgix.net/images/hfqi0zm0/pro... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
55 images 1.1 MB
0 oversized -0 KB
9 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

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
2 fonts (86 KB)
PASS
2 fonts (86 KB)
Info::
2 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

2

86 KB total

Render-blocking

0

of 2

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s 6.0 s 7.0 s 8.0 s 9.0 s FCP 5.1 s LCP 8.9 shttps://fonts.gstatic.com/s/inter/v20/UcCo3FwrK3iLTcviYwYZ8UA3.woff2UcCo3FwrK3iLTcviYwYZ8UA... https://fonts.gstatic.com/s/inter/v20/UcCo3FwrK3iLTcviYwYZ8UA3.woff2 — 71.3 KiB — 0 ms — font-display: swaphttps://cdn.shopify.com/oxygen-v2/26957/18156/37484/3315550/assets/TSTARPRO-Headline-CJhvJIZM.woff2TSTARPRO-Headline-CJhvJ... https://cdn.shopify.com/oxygen-v2/26957/18156/37484/3315550/assets/TSTARPRO-Headline-CJhvJIZM.woff2 — 14.4 KiB — 0 ms — font-display: swap
UcCo3FwrK3iLTcviYwYZ8UA... woff2 swap
Size 71 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
TSTARPRO-Headline-CJhvJ... woff2 swap
Size 14 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
13 hints, 0 missing preconnects
PASS
13 hints, 0 missing preconnects
Info::
Page uses 13 resource hint(s)

Current Resource Hints

preconnect
10
preload
—
dns-prefetch
3
prefetch
—

13 resource hints configured

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
150 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
95% of JavaScript execution is third-party
First-party Third-party 12988ms · 1223KB · €69/mo
cdn.shopify.com
Other
Costly
Execution 4296ms
Transfer 52 KB
Monthly Cost €23/mo
cdn.shopify.com
Other
Costly
Execution 4110ms
Transfer 419 KB
Unused 60%
Monthly Cost €22/mo
Unattributable
Other
Costly
Execution 1613ms
Transfer 0 KB
Monthly Cost €9/mo
Google Tag Manager
Tag Manager
Costly
Execution 873ms
Transfer 200 KB
Unused 29%
Monthly Cost €5/mo
9236cacba5af.cdn4.forter.com
Other
Costly
Execution 686ms
Transfer 214 KB
Unused 40%
Monthly Cost €4/mo
st.dynamicyield.com
Other
Costly
Execution 330ms
Transfer 9 KB
Monthly Cost €2/mo
OneTrust
Consent
Essential
Execution 326ms
Transfer 98 KB
Unused 52%
Monthly Cost €2/mo
cdn.dynamicyield.com
Other
Costly
Execution 324ms
Transfer 42 KB
Monthly Cost €2/mo
web-sdk-cdn.singular.net
Other
Optional
Execution 116ms
Transfer 48 KB
Monthly Cost €1/mo
cdn.dynamicyield.com
Other
Optional
Execution 104ms
Transfer 104 KB
Unused 55%
Monthly Cost €1/mo
cdn.shopify.com
Other
Optional
Execution 95ms
Transfer 7 KB
Monthly Cost €1/mo
OneTrust
Consent
Essential
Execution 58ms
Transfer 9 KB
Monthly Cost €0/mo
cdn.shopify.com
Other
Optional
Execution 56ms
Transfer 20 KB
Monthly Cost €0/mo

These scripts may cost more than they're worth

  • cdn.shopify.com adds 4296ms and costs ~€23/month
  • cdn.shopify.com adds 4110ms and costs ~€22/month
  • Unattributable adds 1613ms and costs ~€9/month
  • Google Tag Manager adds 873ms and costs ~€5/month
  • 9236cacba5af.cdn4.forter.com adds 686ms and costs ~€4/month
  • st.dynamicyield.com adds 330ms and costs ~€2/month
  • cdn.dynamicyield.com adds 324ms and costs ~€2/month

95% 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

cdn.shopify.com takes 4296ms 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

cdn.shopify.com takes 4110ms 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

60% of cdn.shopify.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

Unattributable takes 1613ms 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

Google Tag Manager takes 873ms 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

9236cacba5af.cdn4.forter.com takes 686ms 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

st.dynamicyield.com takes 330ms 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

52% of OneTrust'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

cdn.dynamicyield.com takes 324ms 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 cdn.dynamicyield.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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