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https://gymshark.com

Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
72
GRADE
C
FIX
5
REVIEW
1
PASS
6
INFO
2

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

Mobile Desktop
41
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
80
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
96
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.

1.28 s

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

3.38 s

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

938 ms

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

0.015

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

4.07 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.

9.73 s

Page Load Progression

1.3 s
2.5 s
3.8 s
5.0 s
6.3 s
7.5 s
8.8 s
10.0 s
Checks
14
6 PASS 1 REVIEW 5 FIX
F
Page Weight Budget
Action
72.0 MB transferred, 205 requests
FIX
72.0 MB transferred, 205 requests
Critical::
Page weighs 79.2 MB (72.0 MB transferred)
Warning::
Images are 5.1 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 5.1 MB
Warning::
JavaScript is 3.2 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 3.2 MB
Warning::
205 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 15.1 g CO2 per page load
72.0 MB / 2.4 MB budget
72.0 MB transferred
205 requests
15.1 g CO2 per page load
Other 63.1 MiB 88%
Images 5.1 MiB 7%
JavaScript 3.2 MiB 4%
CSS 188.3 KiB 0%
Fonts 116.6 KiB 0%
HTML 107.1 KiB 0%
Other 69.2 KiB 0%
Other 50.6 KiB 0%
Other 20.8 KiB 0%
Other 795 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 (72.0 MiB of 72.0 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
F
JS Execution Cost
Action
5593ms total JS execution
FIX
5593ms total JS execution
Warning::
https://www.gymshark.com/_next/static/chunks/frame...: 1219ms CPU time
Warning::
Unattributable: 1138ms CPU time
Warning::
https://www.gymshark.com/: 936ms CPU time
Warning::
https://www.gymshark.com/_next/static/chunks/pages...: 669ms CPU time
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-WQX...: 533ms CPU time
Warning::
Third-party scripts: 5593ms (100% of total)

Main Thread Breakdown

Script Evaluation 55% Other 28% Script Parsing & Compilation 5% Style & Layout 5%
ScriptTotalScriptingParse/CompileParty
https://www.gymshark.com/_next/static/chunks/framework-37ae32f58c38fef9.js1219ms1087ms4ms3rd
Unattributable1138ms39ms0ms3rd
https://www.gymshark.com/936ms14ms1ms3rd
https://www.gymshark.com/_next/static/chunks/pages/_app-77dacc2b8f5bc3cc.js669ms543ms92ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-WQXVFFG&gtm_auth=&gtm_preview=&gtm_cookies_win=x533ms435ms24ms3rd
https://10ef4229c7d0.edge.sdk.awswaf.com/10ef4229c7d0/f2cb19c6a7d6/challenge.js379ms320ms41ms3rd
https://js.intercomcdn.com/frame-modern.c43524e8.js249ms216ms25ms3rd
https://www.googletagmanager.com/gtag/js?id=G-PQJ0N2K1QF&cx=c&gtm=4e6461199ms169ms13ms3rd
https://www.googletagmanager.com/gtag/destination?id=AW-823557903&cx=c&gtm=4e6461102ms84ms16ms3rd
https://www.googletagmanager.com/gtag/destination?id=AW-933026149&cx=c&gtm=4e646196ms82ms12ms3rd

Showing top 10 of 11 scripts

F
JS Bundles
Action
37 scripts, 1.8 MB unused
FIX
37 scripts, 1.8 MB unused
Warning::
https://www.gymshark.com/_next/static/chunks/pages...: 659 KB unused (62%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://10ef4229c7d0.edge.sdk.awswaf.com/10ef4229c...: 259 KB unused (52%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://js.intercomcdn.com/frame-modern.c43524e8.j...: 122 KB unused (64%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtag/destination?...: 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: 1.8 MB
1836 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.gymshark.com/_next/static/chunks/pages/_app-77dacc2b8f5bc3cc.js1065 KB659 KB (62%)✓3rd
https://10ef4229c7d0.edge.sdk.awswaf.com/10ef4229c7d0/f2cb19c6a7d6/challenge.js499 KB259 KB (52%)✓3rd
https://js.intercomcdn.com/frame-modern.c43524e8.js192 KB122 KB (64%)✓3rd
https://www.googletagmanager.com/gtag/destination?id=G-PQJ0N2K1QF&cx=c&gtm=4e6461173 KB112 KB (65%)✓3rd
https://js.intercomcdn.com/vendor-modern.df860bed.js144 KB86 KB (60%)✓3rd
https://www.googletagmanager.com/gtag/destination?id=AW-933026149&cx=c&gtm=4e6461133 KB68 KB (51%)✓3rd
https://www.googletagmanager.com/gtag/destination?id=AW-823557903&cx=c&gtm=4e6461133 KB68 KB (51%)✓3rd
https://www.googletagmanager.com/gtm.js?id=GTM-WQXVFFG&gtm_auth=&gtm_preview=&gtm_cookies_win=x210 KB64 KB (31%)✓3rd
https://www.googletagmanager.com/gtag/js?id=G-PQJ0N2K1QF&cx=c&gtm=4e6461173 KB61 KB (35%)✓3rd
https://www.gymshark.com/_next/static/chunks/pages/collections/%5BcollectionSlug%5D/%5B%5B...genderSlug%5D%5D-f2f28871b3adea1e.js0 KB61 KB (80%)✓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
113 images, 0 KB saveable
REVIEW
113 images, 0 KB saveable
Info::
All images are well-optimized
113 images 5.1 MB
0 oversized -0 KB
28 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
11 fonts (117 KB)
PASS
11 fonts (117 KB)
Info::
11 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

11

117 KB total

Render-blocking

0

of 11

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 FCP 1.3 s LCP 3.4 shttps://cdn.gymshark.com/fonts/Montserrat-Regular.woff2Montserrat-Regular.woff2 https://cdn.gymshark.com/fonts/Montserrat-Regular.woff2 — 0 B — 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 — 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://www.gymshark.com/_next/static/media/gymshark-icons.70b7ab93.woffgymshark-icons.70b7ab93... https://www.gymshark.com/_next/static/media/gymshark-icons.70b7ab93.woff — 23.6 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-Regular.woffRoboto-Regular.woff https://cdn.gymshark.com/fonts/Roboto-Regular.woff — 28.7 KiB — 0 ms — font-display: swaphttps://cdn.gymshark.com/fonts/Roboto-Bold.woffRoboto-Bold.woff https://cdn.gymshark.com/fonts/Roboto-Bold.woff — 28.7 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-Medium.woff2Roboto-Medium.woff2 https://cdn.gymshark.com/fonts/Roboto-Medium.woff2 — 16.0 KiB — 0 ms — font-display: swap
Montserrat-Regular.woff2 woff2 swap
Size 0 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 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
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-Regular.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
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
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-Medium.woff2 woff2 swap
Size 16 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)

Fixing the unchecked items could save ~24 KB and ~48 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
205 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 5593ms · 2638KB · $32/mo
www.gymshark.com
Other
Costly
Execution 1219ms
Transfer 44 KB
Monthly Cost $7/mo
Unattributable
Other
Costly
Execution 1138ms
Transfer 0 KB
Monthly Cost $7/mo
www.gymshark.com
Other
Costly
Execution 936ms
Transfer 93 KB
Monthly Cost $5/mo
www.gymshark.com
Other
Costly
Execution 669ms
Transfer 1065 KB
Unused 62%
Monthly Cost $4/mo
Google Tag Manager
Tag Manager
Costly
Execution 533ms
Transfer 210 KB
Unused 31%
Monthly Cost $3/mo
10ef4229c7d0.edge.sdk.awswaf.com
Other
Costly
Execution 379ms
Transfer 499 KB
Unused 52%
Monthly Cost $2/mo
js.intercomcdn.com
Other
Costly
Execution 249ms
Transfer 192 KB
Unused 64%
Monthly Cost $1/mo
Google Tag Manager
Tag Manager
Optional
Execution 199ms
Transfer 173 KB
Unused 35%
Monthly Cost $1/mo
Google Tag Manager
Tag Manager
Optional
Execution 102ms
Transfer 133 KB
Unused 51%
Monthly Cost $1/mo
Google Tag Manager
Tag Manager
Optional
Execution 96ms
Transfer 133 KB
Unused 51%
Monthly Cost $1/mo
Facebook Pixel
Advertising
Optional
Execution 75ms
Transfer 95 KB
Unused 45%
Monthly Cost $0/mo

These scripts may cost more than they're worth

  • www.gymshark.com adds 1219ms and costs ~$7/month
  • Unattributable adds 1138ms and costs ~$7/month
  • www.gymshark.com adds 936ms and costs ~$5/month
  • www.gymshark.com adds 669ms and costs ~$4/month
  • Google Tag Manager adds 533ms and costs ~$3/month
  • 10ef4229c7d0.edge.sdk.awswaf.com adds 379ms and costs ~$2/month
  • js.intercomcdn.com adds 249ms 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 1219ms 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 1138ms 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 936ms 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 669ms 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 533ms 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 379ms 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

js.intercomcdn.com takes 249ms 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

64% 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

51% of Google Tag Manager'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 Google Tag Manager'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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