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https://gymshark.com

Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
66
GRADE
D
FIX
5
REVIEW
1
PASS
6
INFO
2

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

Mobile Desktop
33
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
76
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
77
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.

1.62 s

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

4.31 s

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

2.10 s

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

0.014

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

7.33 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.

13.22 s

Page Load Progression

2.8 s
5.6 s
8.5 s
11.3 s
14.1 s
16.9 s
19.7 s
22.5 s
Checks
14
6 PASS 1 REVIEW 5 FIX
F
Page Weight Budget
Action
110.1 MB transferred, 351 requests
FIX
110.1 MB transferred, 351 requests
Critical::
Page weighs 151.0 MB (110.1 MB transferred)
Warning::
Images are 5.2 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 5.2 MB
Warning::
JavaScript is 3.7 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 3.7 MB
Warning::
351 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 23.1 g CO2 per page load
110.1 MB / 2.4 MB budget
110.1 MB transferred
351 requests
23.1 g CO2 per page load
Other 100.6 MiB 91%
Images 5.2 MiB 5%
JavaScript 3.7 MiB 3%
CSS 187.8 KiB 0%
Fonts 138.8 KiB 0%
Other 114.7 KiB 0%
HTML 106.9 KiB 0%
Other 52.0 KiB 0%
Other 27.8 KiB 0%
Other 7.0 KiB 0%
Other 796 B 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
100% third-party, 0 ms blocking
FIX
100% third-party, 0 ms blocking
Warning::
Third-party code accounts for 100% of page weight (110.1 MiB of 110.1 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
F
JS Execution Cost
Action
12109ms total JS execution
FIX
12109ms total JS execution
Warning::
https://www.gymshark.com/: 3363ms CPU time
Warning::
https://www.gymshark.com/_next/static/chunks/frame...: 2092ms CPU time
Warning::
Unattributable: 1841ms CPU time
Warning::
https://10ef4229c7d0.edge.sdk.awswaf.com/10ef4229c...: 1333ms CPU time
Warning::
https://www.gymshark.com/_next/static/chunks/pages...: 875ms CPU time
Warning::
Third-party scripts: 12109ms (100% of total)

Main Thread Breakdown

Script Evaluation 48% Other 31% Rendering 7% Style & Layout 7% Script Parsing & Compilation 4%
ScriptTotalScriptingParse/CompileParty
https://www.gymshark.com/3363ms23ms1ms3rd
https://www.gymshark.com/_next/static/chunks/framework-37ae32f58c38fef9.js2092ms1639ms7ms3rd
Unattributable1841ms100ms0ms3rd
https://10ef4229c7d0.edge.sdk.awswaf.com/10ef4229c7d0/f2cb19c6a7d6/challenge.js1333ms1162ms54ms3rd
https://www.gymshark.com/_next/static/chunks/pages/_app-77dacc2b8f5bc3cc.js875ms681ms124ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-WQXVFFG&gtm_auth=&gtm_preview=&gtm_cookies_win=x536ms451ms66ms3rd
https://cdn.cookielaw.org/scripttemplates/otSDKStub.js507ms432ms1ms3rd
https://js.intercomcdn.com/vendor-modern.df860bed.js330ms296ms14ms3rd
https://st.dynamicyield.com/st?sec=8786363&ref=https%3A%2F%2Fus.checkout.gymshark.com%2F&scriptVersion=2.82.0&inHead=true&id=0&jsession=gwfal90ltkndhcbzs83kc82w1x6a2t2l&isSesNew=true&landingUrl=www.gymshark.com&dyid_server=0&ctx=%7B%22type%22%3A%22HOMEPAGE%22%7D241ms199ms1ms3rd
https://www.googletagmanager.com/gtag/destination?id=G-PQJ0N2K1QF&cx=c&gtm=4e6411182ms154ms26ms3rd

Showing top 10 of 20 scripts

F
JS Bundles
Action
69 scripts, 2.0 MB unused
FIX
69 scripts, 2.0 MB unused
Warning::
https://www.gymshark.com/_next/static/chunks/pages...: 685 KB unused (62%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://10ef4229c7d0.edge.sdk.awswaf.com/10ef4229c...: 265 KB unused (52%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://js.intercomcdn.com/frame-modern.40aacdf2.j...: 121 KB unused (63%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtag/js?id=G-PQJ0...: 112 KB unused (65%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://js.intercomcdn.com/vendor-modern.df860bed....: 86 KB unused (60%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 2.0 MB
1999 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.gymshark.com/_next/static/chunks/pages/_app-77dacc2b8f5bc3cc.js1113 KB685 KB (62%)✓3rd
https://10ef4229c7d0.edge.sdk.awswaf.com/10ef4229c7d0/f2cb19c6a7d6/challenge.js506 KB265 KB (52%)✓3rd
https://js.intercomcdn.com/frame-modern.40aacdf2.js192 KB121 KB (63%)✓3rd
https://www.googletagmanager.com/gtag/js?id=G-PQJ0N2K1QF&cx=c&gtm=4e6411172 KB112 KB (65%)✓3rd
https://js.intercomcdn.com/vendor-modern.df860bed.js144 KB86 KB (60%)✓3rd
https://jssdkcdns.mparticle.com/js/v2/eu1-ebd2cad076757c498ce604d818b0d8ae/mparticle.js?env=0&plan_id=gymshark_data_plan_shop133 KB81 KB (61%)✓3rd
https://www.gymshark.com/_next/static/chunks/pages/collections/%5BcollectionSlug%5D/%5B%5B...genderSlug%5D%5D-f2f28871b3adea1e.js21 KB61 KB (80%)✓3rd
https://www.gymshark.com/_next/static/chunks/pages/collections/%5BcollectionSlug%5D/%5B%5B...genderSlug%5D%5D-f2f28871b3adea1e.js0 KB61 KB (80%)✓3rd
https://www.googletagmanager.com/gtag/destination?id=AW-933026149&cx=c&gtm=4e6411132 KB59 KB (44%)✓3rd
https://cdn.dynamicyield.com/api/8786363/api_static.js102 KB58 KB (57%)✓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: private, no-store
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

private, no-store

DirectiveValueMeaning
private—Only browser cache, not CDN/proxy
no-store—Never cache this response
B
Image Optimization
129 images, 0 KB saveable
REVIEW
129 images, 0 KB saveable
Info::
All images are well-optimized
129 images 5.2 MB
0 oversized -0 KB
39 legacy format
0 missing dimensions CLS risk
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
10 fonts (139 KB)
PASS
10 fonts (139 KB)
Info::
10 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

10

139 KB total

Render-blocking

0

of 10

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 FCP 1.6 s LCP 4.3 shttps://cdn.gymshark.com/fonts/Montserrat-Regular.woff2Montserrat-Regular.woff2 https://cdn.gymshark.com/fonts/Montserrat-Regular.woff2 — 28.6 KiB — 0 ms — font-display: swaphttps://cdn.gymshark.com/fonts/Montserrat-Bold.woff2Montserrat-Bold.woff2 https://cdn.gymshark.com/fonts/Montserrat-Bold.woff2 — 19.5 KiB — 0 ms — font-display: swaphttps://cdn.gymshark.com/fonts/Roboto-Regular.woff2Roboto-Regular.woff2 https://cdn.gymshark.com/fonts/Roboto-Regular.woff2 — 22.3 KiB — 0 ms — font-display: swaphttps://cdn.gymshark.com/fonts/Roboto-Bold.woff2Roboto-Bold.woff2 https://cdn.gymshark.com/fonts/Roboto-Bold.woff2 — 0 B — 0 ms — font-display: swaphttps://www.gymshark.com/_next/static/media/gymshark-icons.70b7ab93.woffgymshark-icons.70b7ab93... https://www.gymshark.com/_next/static/media/gymshark-icons.70b7ab93.woff — 23.5 KiB — 0 ms — font-display: swaphttps://cdn.gymshark.com/fonts/Roboto-Regular.woff2Roboto-Regular.woff2 https://cdn.gymshark.com/fonts/Roboto-Regular.woff2 — 0 B — 0 ms — font-display: swaphttps://cdn.gymshark.com/fonts/Roboto-Bold.woff2Roboto-Bold.woff2 https://cdn.gymshark.com/fonts/Roboto-Bold.woff2 — 0 B — 0 ms — font-display: swaphttps://cdn.gymshark.com/fonts/Roboto-Medium.woff2Roboto-Medium.woff2 https://cdn.gymshark.com/fonts/Roboto-Medium.woff2 — 16.0 KiB — 0 ms — font-display: swaphttps://cdn.gymshark.com/fonts/Montserrat-Bold.woff2Montserrat-Bold.woff2 https://cdn.gymshark.com/fonts/Montserrat-Bold.woff2 — 0 B — 0 ms — font-display: swaphttps://cdn.gymshark.com/fonts/Roboto-Bold.woffRoboto-Bold.woff https://cdn.gymshark.com/fonts/Roboto-Bold.woff — 28.8 KiB — 0 ms — font-display: swap
Montserrat-Regular.woff2 woff2 swap
Size 29 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Montserrat-Bold.woff2 woff2 swap
Size 20 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Roboto-Regular.woff2 woff2 swap
Size 22 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Roboto-Bold.woff2 woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
gymshark-icons.70b7ab93... woff swap
Size 24 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
Roboto-Regular.woff2 woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Roboto-Bold.woff2 woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Roboto-Medium.woff2 woff2 swap
Size 16 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Montserrat-Bold.woff2 woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Roboto-Bold.woff woff swap
Size 29 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
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)

Fixing the unchecked items could save ~16 KB and ~32 ms

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
351 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
100% of JavaScript execution is third-party
First-party Third-party 12109ms · 3031KB · $69/mo
www.gymshark.com
Other
Costly
Execution 3363ms
Transfer 92 KB
Monthly Cost $19/mo
www.gymshark.com
Other
Costly
Execution 2092ms
Transfer 42 KB
Monthly Cost $12/mo
Unattributable
Other
Costly
Execution 1841ms
Transfer 0 KB
Monthly Cost $11/mo
10ef4229c7d0.edge.sdk.awswaf.com
Other
Costly
Execution 1333ms
Transfer 506 KB
Unused 52%
Monthly Cost $8/mo
www.gymshark.com
Other
Costly
Execution 875ms
Transfer 1113 KB
Unused 62%
Monthly Cost $5/mo
Google Tag Manager
Tag Manager
Costly
Execution 536ms
Transfer 209 KB
Unused 25%
Monthly Cost $3/mo
OneTrust
Consent
Essential
Execution 507ms
Transfer 9 KB
Monthly Cost $3/mo
js.intercomcdn.com
Other
Costly
Execution 330ms
Transfer 144 KB
Unused 60%
Monthly Cost $2/mo
st.dynamicyield.com
Other
Costly
Execution 241ms
Transfer 4 KB
Monthly Cost $1/mo
Google Tag Manager
Tag Manager
Optional
Execution 182ms
Transfer 172 KB
Unused 33%
Monthly Cost $1/mo
cdn.dynamicyield.com
Other
Optional
Execution 119ms
Transfer 102 KB
Unused 57%
Monthly Cost $1/mo
analytics.tiktok.com
Other
Optional
Execution 117ms
Transfer 110 KB
Unused 51%
Monthly Cost $1/mo
res4.applovin.com
Other
Optional
Execution 116ms
Transfer 31 KB
Monthly Cost $1/mo
Intercom Widget
Chat
Optional
Execution 88ms
Transfer 4 KB
Monthly Cost $0/mo
Google Tag Manager
Tag Manager
Optional
Execution 74ms
Transfer 132 KB
Unused 44%
Monthly Cost $0/mo
Google Tag Manager
Tag Manager
Optional
Execution 70ms
Transfer 132 KB
Unused 44%
Monthly Cost $0/mo
OneTrust
Consent
Essential
Execution 67ms
Transfer 80 KB
Unused 59%
Monthly Cost $0/mo
Facebook Pixel
Advertising
Optional
Execution 54ms
Transfer 95 KB
Unused 35%
Monthly Cost $0/mo
www.gymshark.com
Other
Optional
Execution 53ms
Transfer 38 KB
Monthly Cost $0/mo
Facebook Pixel
Advertising
Optional
Execution 52ms
Transfer 16 KB
Monthly Cost $0/mo

These scripts may cost more than they're worth

  • www.gymshark.com adds 3363ms and costs ~$19/month
  • www.gymshark.com adds 2092ms and costs ~$12/month
  • Unattributable adds 1841ms and costs ~$11/month
  • 10ef4229c7d0.edge.sdk.awswaf.com adds 1333ms and costs ~$8/month
  • www.gymshark.com adds 875ms and costs ~$5/month
  • Google Tag Manager adds 536ms and costs ~$3/month
  • js.intercomcdn.com adds 330ms and costs ~$2/month
  • st.dynamicyield.com adds 241ms and costs ~$1/month

100% 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

www.gymshark.com takes 3363ms 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

www.gymshark.com takes 2092ms 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

Unattributable takes 1841ms 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

10ef4229c7d0.edge.sdk.awswaf.com takes 1333ms 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 10ef4229c7d0.edge.sdk.awswaf.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

www.gymshark.com takes 875ms 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

62% of www.gymshark.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

Google Tag Manager takes 536ms 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

js.intercomcdn.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

60% of js.intercomcdn.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

st.dynamicyield.com takes 241ms 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

57% 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

51% 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

59% 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

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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