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https://www.decathlon.com

Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
72
GRADE
C
FIX
4
REVIEW
2
PASS
8
INFO
2

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

Mobile Desktop
26
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
95
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
81
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
85
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.

5.35 s

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

14.67 s

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

6.40 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.

19.27 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.

46.30 s

Page Load Progression

1.2 s
2.4 s
3.6 s
4.9 s
6.1 s
7.3 s
8.5 s
9.7 s
Checks
16
8 PASS 2 REVIEW 4 FIX
F
Page Weight Budget
Action
9.4 MB transferred, 418 requests
FIX
9.4 MB transferred, 418 requests
Critical::
Page weighs 17.1 MB (9.4 MB transferred)
Warning::
Images are 4.5 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 4.5 MB
Warning::
JavaScript is 2.8 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 2.8 MB
Info::
Fonts are 353 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 353 KB
Warning::
418 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 2.0 g CO2 per page load
9.4 MB / 2.4 MB budget
9.4 MB transferred
418 requests
2.0 g CO2 per page load
Images 4.5 MiB 48%
JavaScript 2.8 MiB 30%
Other 1.3 MiB 14%
Fonts 353.2 KiB 4%
Other 131.1 KiB 1%
CSS 115.8 KiB 1%
HTML 95.6 KiB 1%
Other 27.0 KiB 0%
Other 10.9 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

Subset fonts to include only used characters, or switch to system font stacks.

Why this matters

Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).

Source: web.dev font loading

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
27310ms total JS execution
FIX
27310ms total JS execution
Warning::
https://www.decathlon.com/: 5207ms CPU time
Warning::
Unattributable: 3375ms CPU time
Warning::
https://cdn.rebuyengine.com/onsite/js/rebuy.js?sho...: 1799ms CPU time
Warning::
https://cdn.dynamicyield.com/api/8773860/api_stati...: 1594ms CPU time
Warning::
https://cdn.rebuyengine.com/onsite/js/vendors.js?i...: 1506ms CPU time
Warning::
Third-party scripts: 18999ms (70% of total)

Main Thread Breakdown

Script Evaluation 50% Style & Layout 19% Other 18% Script Parsing & Compilation 7%
ScriptTotalScriptingParse/CompileParty
https://www.decathlon.com/5207ms442ms72ms1st
Unattributable3375ms267ms0ms3rd
https://cdn.rebuyengine.com/onsite/js/rebuy.js?shop=decathlon-usa.myshopify.com1799ms987ms739ms3rd
https://cdn.dynamicyield.com/api/8773860/api_static.js1594ms552ms60ms3rd
https://cdn.rebuyengine.com/onsite/js/vendors.js?id=0b003f48048b80a123601506ms686ms44ms3rd
https://scripts.clarity.ms/0.8.59/clarity.js1030ms917ms14ms3rd
https://cdn.rebuyengine.com/onsite/js/global.js?build=1775244697958ms755ms113ms3rd
https://www.decathlon.com/cdn/wpm/b98d3e97aw95287a42p6e310ef5m9f58c5a0m.js938ms732ms27ms1st
https://assets.gorgias.chat/build/static/js/557.f9e30f4c6d8d87de.js744ms642ms20ms3rd
https://www.googletagmanager.com/gtag/js?id=G-NQJCP882N4646ms552ms86ms3rd

Showing top 10 of 52 scripts

F
JS Bundles
Action
208 scripts, 804 KB unused
FIX
208 scripts, 804 KB unused
Warning::
https://cdn.rebuyengine.com/onsite/js/global.js?bu...: 111 KB unused (51%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtag/js?id=GT-MJW...: 104 KB unused (77%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://cdn.rebuyengine.com/onsite/js/vendors.js?i...: 77 KB unused (100%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://cdn.dynamicyield.com/api/8773860/api_stati...: 69 KB unused (67%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtag/js?id=GT-MJW...: 64 KB unused (47%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 804 KB
804 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://cdn.rebuyengine.com/onsite/js/global.js?build=1775244697221 KB111 KB (51%)✓3rd
https://www.googletagmanager.com/gtag/js?id=GT-MJWCF3J&cx=c&gtm=4e6411135 KB104 KB (77%)✓3rd
https://cdn.rebuyengine.com/onsite/js/vendors.js?id=0b003f48048b80a1236078 KB77 KB (100%)✓3rd
https://cdn.dynamicyield.com/api/8773860/api_static.js104 KB69 KB (67%)✓3rd
https://www.googletagmanager.com/gtag/js?id=GT-MJWCF3J135 KB64 KB (47%)✓3rd
https://www.googletagmanager.com/gtag/js?id=G-NQJCP882N4173 KB62 KB (36%)✓3rd
https://static.returngo.ai/master.returngo.ai/returngo.min.js?shop=decathlon-usa.myshopify.com48 KB42 KB (89%)✓3rd
https://assets.gorgias.chat/build/static/js/279.58c6a32e6ae4fc54.js93 KB41 KB (45%)✓3rd
https://static-tracking.klaviyo.com/onsite/js/build-preview/commit-f6f00cac0c842ff6b918911ae9159db809c1b007/Render.12bfc6d3a0a9b939b8c4.js52 KB37 KB (72%)✓3rd
https://cdn.9gtb.com/script.js?rev=9b8201f61 KB32 KB (54%)✓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.
Info::
ETag present — enables conditional (304) responses

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

B
Third-Party Impact
59% third-party, 0 ms blocking
REVIEW
59% third-party, 0 ms blocking
Warning::
Third-party code accounts for 59% of page weight (5.5 MiB of 9.4 MiB)
Info::
Third-party blocking time is low (0 ms)
41%
59%
First-party Third-party
C
Image Optimization
Action
51 images, 0 KB saveable
REVIEW
51 images, 0 KB saveable
Warning::
https://cdn.shopify.com/s/files/1/1330/6287/files/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn.shopify.com/s/files/1/1330/6287/files/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn.shopify.com/s/files/1/1752/4727/files/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn.shopify.com/s/files/1/1330/6287/files/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn.shopify.com/s/files/1/1752/4727/files/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
51 images 4.5 MB
0 oversized -0 KB
12 legacy format
5 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

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
9 fonts (353 KB)
PASS
9 fonts (353 KB)
Info::
9 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

9

353 KB total

Render-blocking

0

of 9

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 2.0 s 4.0 s 6.0 s 8.0 s 10.0 s 12.0 s 14.0 s FCP 5.4 s LCP 14.7 shttps://www.decathlon.com/cdn/shop/t/334/assets/Decathlon-Brand-SemiBold.woff2?v=4101535601310826581750076865Decathlon-Brand-SemiBol... https://www.decathlon.com/cdn/shop/t/334/assets/Decathlon-Brand-SemiBold.woff2?v=4101535601310826581750076865 — 0 B — 0 ms — font-display: swaphttps://www.decathlon.com/cdn/shop/t/334/assets/Decathlon-Display-SemiBold.woff2?v=100345316253960588891750076865Decathlon-Display-SemiB... https://www.decathlon.com/cdn/shop/t/334/assets/Decathlon-Display-SemiBold.woff2?v=100345316253960588891750076865 — 0 B — 0 ms — font-display: swaphttps://www.decathlon.com/cdn/shop/t/334/assets/Decathlon-Text-Medium.woff2?v=52324173899180483681750076865Decathlon-Text-Medium.w... https://www.decathlon.com/cdn/shop/t/334/assets/Decathlon-Text-Medium.woff2?v=52324173899180483681750076865 — 0 B — 0 ms — font-display: swaphttps://www.decathlon.com/cdn/shop/t/334/assets/Decathlon-Text-SemiBold.woff2?v=2220433650020876521750076866Decathlon-Text-SemiBold... https://www.decathlon.com/cdn/shop/t/334/assets/Decathlon-Text-SemiBold.woff2?v=2220433650020876521750076866 — 0 B — 0 ms — font-display: swaphttps://www.decathlon.com/cdn/fonts/assistant/assistant_n4.9120912a469cad1cc292572851508ca49d12e768.woff2assistant_n4.9120912a46... https://www.decathlon.com/cdn/fonts/assistant/assistant_n4.9120912a469cad1cc292572851508ca49d12e768.woff2 — 12.9 KiB — 0 ms — font-display: swaphttps://cdn.rebuyengine.com/onsite/webfonts/fa-light-300.woff2fa-light-300.woff2 https://cdn.rebuyengine.com/onsite/webfonts/fa-light-300.woff2 — 185.8 KiB — 0 ms — font-display: swaphttps://cdn.shopify.com/s/files/1/1330/6287/files/Decathlon-Display-Bold.ttf?v=1759350281Decathlon-Display-Bold.ttf https://cdn.shopify.com/s/files/1/1330/6287/files/Decathlon-Display-Bold.ttf?v=1759350281 — 51.5 KiB — 0 ms — font-display: swaphttps://cdn.shopify.com/s/files/1/1330/6287/files/Decathlon-Display-SemiBold.ttf?v=1759350281Decathlon-Display-SemiB... https://cdn.shopify.com/s/files/1/1330/6287/files/Decathlon-Display-SemiBold.ttf?v=1759350281 — 51.6 KiB — 0 ms — font-display: swaphttps://cdn.shopify.com/s/files/1/1330/6287/files/Decathlon-Display-Medium.ttf?v=1759350281Decathlon-Display-Mediu... https://cdn.shopify.com/s/files/1/1330/6287/files/Decathlon-Display-Medium.ttf?v=1759350281 — 51.5 KiB — 0 ms — font-display: swap
Decathlon-Brand-SemiBol... woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Decathlon-Display-SemiB... woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Decathlon-Text-Medium.w... woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Decathlon-Text-SemiBold... woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
assistant_n4.9120912a46... woff2 swap
Size 13 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
fa-light-300.woff2 woff2 swap
Size 186 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
Decathlon-Display-Bold.ttf ttf swap
Size 51 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
Decathlon-Display-SemiB... ttf swap
Size 52 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
Decathlon-Display-Mediu... ttf swap
Size 51 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 ~139 KB and ~278 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
25 hints, 0 missing preconnects
PASS
25 hints, 0 missing preconnects
Info::
Page uses 25 resource hint(s)

Current Resource Hints

preconnect
8
preload
6
dns-prefetch
4
prefetch
7

25 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
418 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
70% of JavaScript execution is third-party
First-party Third-party 18999ms · 1795KB · €101/mo
Unattributable
Other
Costly
Execution 3375ms
Transfer 0 KB
Monthly Cost €18/mo
cdn.rebuyengine.com
Other
Costly
Execution 1799ms
Transfer 20 KB
Monthly Cost €10/mo
cdn.dynamicyield.com
Other
Costly
Execution 1594ms
Transfer 104 KB
Unused 67%
Monthly Cost €8/mo
cdn.rebuyengine.com
Other
Costly
Execution 1506ms
Transfer 78 KB
Unused 100%
Monthly Cost €8/mo
Microsoft Clarity
Session Replay
Costly
Execution 1030ms
Transfer 26 KB
Monthly Cost €5/mo
cdn.rebuyengine.com
Other
Costly
Execution 958ms
Transfer 221 KB
Unused 51%
Monthly Cost €5/mo
assets.gorgias.chat
Other
Costly
Execution 744ms
Transfer 36 KB
Monthly Cost €4/mo
Google Tag Manager
Tag Manager
Costly
Execution 646ms
Transfer 173 KB
Unused 36%
Monthly Cost €3/mo
static.klaviyo.com
Other
Costly
Execution 642ms
Transfer 10 KB
Monthly Cost €3/mo
cdn.rebuyengine.com
Other
Costly
Execution 606ms
Transfer 32 KB
Unused 71%
Monthly Cost €3/mo
assets.gorgias.chat
Other
Costly
Execution 565ms
Transfer 93 KB
Unused 45%
Monthly Cost €3/mo
static-tracking.klaviyo.com
Other
Costly
Execution 554ms
Transfer 52 KB
Unused 72%
Monthly Cost €3/mo
st.dynamicyield.com
Other
Costly
Execution 530ms
Transfer 5 KB
Monthly Cost €3/mo
static.klaviyo.com
Other
Costly
Execution 444ms
Transfer 10 KB
Monthly Cost €2/mo
assets.gorgias.chat
Other
Costly
Execution 428ms
Transfer 21 KB
Monthly Cost €2/mo
static-tracking.klaviyo.com
Other
Costly
Execution 407ms
Transfer 8 KB
Monthly Cost €2/mo
cdn-app.cart-bot.net
Other
Costly
Execution 401ms
Transfer 37 KB
Monthly Cost €2/mo
Google Tag Manager
Tag Manager
Costly
Execution 354ms
Transfer 135 KB
Unused 47%
Monthly Cost €2/mo
Facebook Pixel
Advertising
Costly
Execution 260ms
Transfer 95 KB
Unused 34%
Monthly Cost €1/mo
Facebook Pixel
Advertising
Optional
Execution 197ms
Transfer 39 KB
Monthly Cost €1/mo
cdn.nfcube.com
Other
Optional
Execution 193ms
Transfer 20 KB
Monthly Cost €1/mo
cdn.rebuyengine.com
Other
Optional
Execution 148ms
Transfer 1 KB
Monthly Cost €1/mo
cdn.nfcube.com
Other
Optional
Execution 148ms
Transfer 20 KB
Monthly Cost €1/mo
cdn.rebuyengine.com
Other
Optional
Execution 129ms
Transfer 15 KB
Monthly Cost €1/mo
cdn.9gtb.com
Other
Optional
Execution 128ms
Transfer 61 KB
Unused 54%
Monthly Cost €1/mo
cdn.dynamicyield.com
Other
Optional
Execution 116ms
Transfer 18 KB
Monthly Cost €1/mo
na.shgcdn3.com
Other
Optional
Execution 109ms
Transfer 27 KB
Monthly Cost €1/mo
size-guides-prod.esc-apps-cdn.com
Other
Optional
Execution 105ms
Transfer 49 KB
Monthly Cost €1/mo
cdn.shopify.com
Other
Optional
Execution 103ms
Transfer 39 KB
Unused 78%
Monthly Cost €1/mo
config.gorgias.chat
Other
Optional
Execution 102ms
Transfer 13 KB
Monthly Cost €1/mo
cdn.aggle.net
Other
Optional
Execution 97ms
Transfer 19 KB
Monthly Cost €1/mo
Google Tag Manager
Tag Manager
Optional
Execution 94ms
Transfer 135 KB
Unused 77%
Monthly Cost €0/mo
static-tracking.klaviyo.com
Other
Optional
Execution 84ms
Transfer 14 KB
Monthly Cost €0/mo
light.spicegems.org
Other
Optional
Execution 84ms
Transfer 33 KB
Monthly Cost €0/mo
cdn.shopify.com
Other
Optional
Execution 81ms
Transfer 7 KB
Monthly Cost €0/mo
static-tracking.klaviyo.com
Other
Optional
Execution 74ms
Transfer 2 KB
Monthly Cost €0/mo
assets.gorgias.chat
Other
Optional
Execution 59ms
Transfer 42 KB
Monthly Cost €0/mo
backinstock.useamp.com
Other
Optional
Execution 54ms
Transfer 36 KB
Monthly Cost €0/mo
static.returngo.ai
Other
Optional
Execution 50ms
Transfer 48 KB
Unused 89%
Monthly Cost €0/mo

These scripts may cost more than they're worth

  • Unattributable adds 3375ms and costs ~€18/month
  • cdn.rebuyengine.com adds 1799ms and costs ~€10/month
  • cdn.dynamicyield.com adds 1594ms and costs ~€8/month
  • cdn.rebuyengine.com adds 1506ms and costs ~€8/month
  • Microsoft Clarity adds 1030ms and costs ~€5/month
  • cdn.rebuyengine.com adds 958ms and costs ~€5/month
  • assets.gorgias.chat adds 744ms and costs ~€4/month
  • Google Tag Manager adds 646ms and costs ~€3/month
  • static.klaviyo.com adds 642ms and costs ~€3/month
  • cdn.rebuyengine.com adds 606ms and costs ~€3/month
  • assets.gorgias.chat adds 565ms and costs ~€3/month
  • static-tracking.klaviyo.com adds 554ms and costs ~€3/month
  • st.dynamicyield.com adds 530ms and costs ~€3/month
  • static.klaviyo.com adds 444ms and costs ~€2/month
  • assets.gorgias.chat adds 428ms and costs ~€2/month
  • static-tracking.klaviyo.com adds 407ms and costs ~€2/month
  • cdn-app.cart-bot.net adds 401ms and costs ~€2/month
  • Google Tag Manager adds 354ms and costs ~€2/month
  • Facebook Pixel adds 260ms and costs ~€1/month

70% of JavaScript execution time comes from third-party scripts.

Why this matters

Third-party scripts (analytics, ads, social, A/B testing) often dominate execution time — every one is a perf-and-privacy tax.

Learn more ▾

Each third-party script is a black box: you don't control when it loads, what it executes, or how much it grows. They often account for a major share of total blocking time on average sites (HTTP Archive's Web Almanac documents the trend). Audit which ones you actually need, defer the rest, and use facade patterns (lite-youtube, lite-vimeo) for embedded media.

Source: web.dev / HTTP Archive Web Almanac

Unattributable takes 3375ms 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.rebuyengine.com takes 1799ms 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.dynamicyield.com takes 1594ms 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

67% 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

cdn.rebuyengine.com takes 1506ms 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

100% of cdn.rebuyengine.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

Microsoft Clarity takes 1030ms 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.rebuyengine.com takes 958ms 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

51% of cdn.rebuyengine.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.gorgias.chat takes 744ms 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 646ms 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

static.klaviyo.com takes 642ms 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.rebuyengine.com takes 606ms 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 cdn.rebuyengine.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.gorgias.chat takes 565ms 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

static-tracking.klaviyo.com takes 554ms 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

72% of static-tracking.klaviyo.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 530ms 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

static.klaviyo.com takes 444ms 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

assets.gorgias.chat takes 428ms 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

static-tracking.klaviyo.com takes 407ms 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-app.cart-bot.net takes 401ms 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 354ms 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

Facebook Pixel takes 260ms 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

54% of cdn.9gtb.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

78% 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

77% 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

89% of static.returngo.ai'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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