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https://skims.com

Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
73
GRADE
C
FIX
5
REVIEW
1
PASS
6
INFO
2

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

Mobile Desktop
70
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.

1.39 s

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

2.77 s

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

193 ms

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

0.002

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

2.31 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.

4.11 s

Page Load Progression

406 ms
812 ms
1.2 s
1.6 s
2.0 s
2.4 s
2.8 s
3.2 s
Checks
14
6 PASS 1 REVIEW 5 FIX
F
Page Weight Budget
Action
3.7 MB transferred, 127 requests
FIX
3.7 MB transferred, 127 requests
Warning::
Page weighs 8.4 MB (3.7 MB transferred)
Warning::
Images are 2.0 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 2.0 MB
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::
127 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 0.78 g CO2 per page load
3.7 MB / 2.4 MB budget
3.7 MB transferred
127 requests
0.78 g CO2 per page load
Images 2.0 MiB 53%
JavaScript 1.3 MiB 35%
Other 127.3 KiB 3%
Fonts 85.7 KiB 2%
HTML 71.3 KiB 2%
Other 57.9 KiB 2%
Other 42.8 KiB 1%
CSS 30.0 KiB 1%
Other 5.5 KiB 0%
Other 2.2 KiB 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Over budget

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

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

D
Third-Party Impact
Action
96% third-party, 0 ms blocking
FIX
96% third-party, 0 ms blocking
Warning::
Third-party code accounts for 96% of page weight (3.6 MiB of 3.7 MiB)
Info::
Third-party blocking time is low (0 ms)
96%
First-party Third-party
D
JS Execution Cost
Action
3238ms total JS execution
FIX
3238ms total JS execution
Warning::
https://cdn.shopify.com/oxygen-v2/26957/18156/3748...: 990ms CPU time
Warning::
https://cdn.shopify.com/oxygen-v2/26957/18156/3748...: 981ms CPU time
Warning::
Unattributable: 431ms CPU time
Info::
https://www.googletagmanager.com/gtm.js?id=GTM-N9X...: 233ms CPU time
Info::
https://skims.com/en-br: 192ms CPU time
Warning::
Third-party scripts: 3046ms (94% of total)

Main Thread Breakdown

Script Evaluation 72% Other 15% Style & Layout 4% Script Parsing & Compilation 3%
ScriptTotalScriptingParse/CompileParty
https://cdn.shopify.com/oxygen-v2/26957/18156/37484/3315550/assets/index-DyRoOIe0.js990ms894ms0ms3rd
https://cdn.shopify.com/oxygen-v2/26957/18156/37484/3315550/assets/root-gDyipPt0.js981ms830ms3ms3rd
Unattributable431ms82ms0ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-N9XLT5N233ms197ms28ms3rd
https://skims.com/en-br192ms9ms11ms1st
https://9236cacba5af.cdn4.forter.com/sn/9236cacba5af/script.js179ms158ms15ms3rd
https://st.dynamicyield.com/st?sec=8777639&ref=&scriptVersion=2.83.0&inHead=true&id=-630503701243097639&jsession=8vvge04qzwa64v582qncwc381sbq5l56&isSesNew=false&landingUrl=&dyid_server=-630503701243097639&ctx=%7B%22type%22%3A%22HOMEPAGE%22%2C%22data%22%3A%5B%5D%2C%22lng%22%3A%22en_BR%22%7D96ms88ms3ms3rd
https://cdn.cookielaw.org/scripttemplates/202306.1.0/otBannerSdk.js78ms50ms13ms3rd
https://cdn.dynamicyield.com/api/8777639/api_static.js58ms46ms11ms3rd
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 (30%)
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 (30%)✓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=1775635930&event_id=c2d04a9e-f7f9-4b11-a33d-2f34a7cd70b8&conversion_event=true&k=SDID&a=skims_body_inc_f0f5bbdc&p=Web&i=https%3A%2F%2Fskims.com&screen_height=600&screen_width=800&sdk=WebSDK-v1.4.10&singular_instance_id=5df01ca1-f474-4378-8efd-27aa98143146&sdid=0e9ab680-ce9c-4700-ad5c-b6da335f3aba&storage_type=local&timezone=GMT%2B0000&touchpoint_timestamp=1775635930&u=0e9ab680-ce9c-4700-ad5c-b6da335f3aba&n=__PAGE_VISIT__&is_revenue_event=false&first=true&is_after_conversion_event=false&s=37a404cb-4dc5-4361-89a4-400efeb7ea55&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=0e9ab680-ce9c-4700-ad5c-b6da335f3aba&os=Linux&lag=1&h=678aef2feba7f98ef3f3e1bdad331cd0244a10d20 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
30 images, 0 KB saveable
REVIEW
30 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.
30 images 2.0 MB
0 oversized -0 KB
12 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 500 ms 1.0 s 1.5 s 2.0 s 2.5 s FCP 1.4 s LCP 2.8 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
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
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
127 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
94% of JavaScript execution is third-party
First-party Third-party 3046ms · 1096KB · €16/mo
cdn.shopify.com
Other
Costly
Execution 990ms
Transfer 52 KB
Monthly Cost €5/mo
cdn.shopify.com
Other
Costly
Execution 981ms
Transfer 419 KB
Unused 60%
Monthly Cost €5/mo
Unattributable
Other
Costly
Execution 431ms
Transfer 0 KB
Monthly Cost €2/mo
Google Tag Manager
Tag Manager
Costly
Execution 233ms
Transfer 200 KB
Unused 30%
Monthly Cost €1/mo
9236cacba5af.cdn4.forter.com
Other
Optional
Execution 179ms
Transfer 214 KB
Unused 40%
Monthly Cost €1/mo
st.dynamicyield.com
Other
Optional
Execution 96ms
Transfer 9 KB
Monthly Cost €1/mo
OneTrust
Consent
Essential
Execution 78ms
Transfer 98 KB
Unused 52%
Monthly Cost €0/mo
cdn.dynamicyield.com
Other
Optional
Execution 58ms
Transfer 104 KB
Unused 55%
Monthly Cost €0/mo

These scripts may cost more than they're worth

  • cdn.shopify.com adds 990ms and costs ~€5/month
  • cdn.shopify.com adds 981ms and costs ~€5/month
  • Unattributable adds 431ms and costs ~€2/month
  • Google Tag Manager adds 233ms and costs ~€1/month

94% 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 990ms 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 981ms 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 431ms 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 233ms 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

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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