Performance
· 23 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
945 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
2.40 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
56 ms
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.
1.90 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.
2.86 s
Page Load Progression
FPage Weight BudgetAction4.4 MB transferred, 185 requestsFIX
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
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.
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.
High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.
Source: web.dev
FJS BundlesAction119 scripts, 640 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtag/js?id=G-DE42LVPV79&cx=c>m=4e67m0 | 180 KB | 119 KB (66%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-17615131819&cx=c>m=4e67m0 | 153 KB | 109 KB (71%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-NZB5Q3Q6 | 151 KB | 84 KB (55%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-DE42LPVV79&cx=c>m=4e67m0 | 145 KB | 69 KB (48%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-DE42LVPV79 | 180 KB | 66 KB (37%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-17615131819 | 153 KB | 60 KB (39%) | ✓ | 3rd |
| https://cdn.jsdelivr.net/npm/swiper@11/swiper-bundle.min.js | 43 KB | 42 KB (97%) | ✓ | 3rd |
| https://rentcoolcubes.com/cdn/wpm/b0b92dcedw658847c9p94194e39m8bc44e9fm.js | 68 KB | 35 KB (53%) | ✓ | 1st |
| https://rentcoolcubes.com/cdn/shop/t/14/assets/vendor-scripts-v14.js | 37 KB | 29 KB (79%) | ✓ | 1st |
| https://rentcoolcubes.com/cdn/shop/t/14/assets/theme.js?v=140924482945350573091746543398 | 35 KB | 27 KB (78%) | ✓ | 1st |
Consider code splitting or tree shaking to reduce unused code.
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.
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.
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.
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.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
DPage Weight InventoryAction185 resources · 4.4 MB · 640 KB savings availableFIX
~639.6 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 185 resources | 4.4 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction21 images, 0 KB saveableREVIEW
Set explicit width and height to prevent CLS.
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.
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.
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.
Performance issues directly impact user engagement and conversion rates.
Set explicit width and height to prevent CLS.
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.
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.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
CJS Execution CostAction1225ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://rentcoolcubes.com/ | 387ms | 53ms | 6ms | 1st |
| Unattributable | 240ms | 7ms | 0ms | 1st |
| https://js.hs-analytics.net/analytics/1785157200000/43642784.js | 168ms | 119ms | 3ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-DE42LVPV79 | 145ms | 133ms | 11ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-17615131819 | 98ms | 86ms | 11ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-DE42LPVV79&cx=c>m=4e67m0 | 79ms | 69ms | 9ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-NZB5Q3Q6 | 58ms | 45ms | 12ms | 3rd |
| https://rentcoolcubes.com/cdn/s/trekkie.storefront.51e77662fd67e0d47c7238acfeab529dafb90214.min.js | 51ms | 46ms | 4ms | 1st |
BMain HTML Cache-ControlNo Cache-Control header on main HTML responseREVIEW
AThird-Party Impact30% third-party, 0 ms blockingPASS
A+Text CompressionAll text resources are compressedPASS
A+Font LoadingNo web fonts (system fonts)PASS
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
A+HTTP/3 (QUIC)HTTP/3 advertised via Alt-SvcPASS
A+Compression AlgorithmMain response uses brotliPASS
A+LCP Image PreloadLCP preload audit not availablePASS
A+Server-Timing Observability1 Server-Timing entries advertisedPASS
AServer Response Intelligence2 server-response signal(s) detectedPASS
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
This site is hosted on green energy infrastructure
Provider: Cloudflare
Network Waterfall185 requests over 4084msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
HubSpot Analytics js.hs-analytics.net | Analytics | 168ms | 43 KB | — | €1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 145ms | 180 KB | 37% | €1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 98ms | 153 KB | 39% | €1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 79ms | 145 KB | 48% | €0/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 58ms | 151 KB | 55% | €0/mo | Optional |
45% of JavaScript execution time comes from third-party scripts.
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
55% of Google Tag Manager's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
Real-User Performance (CrUX)Field metrics from the Chrome User Experience ReportINFO
Chrome User Experience (CrUX)
Real-user metrics from the Chrome UX Report (2026-06-28 — 2026-07-25)
LCP (p75)
0 ms
0% good
INP (p75)
0 ms
0% good
CLS (p75)
0.000
99% good
FCP (p75)
2711 ms
TTFB (p75)
697 ms
Image Optimization39 images, 6484 KB total, 1483 KB wastedINFO
Image Optimization Audit
Total Images
39
Total Size
6484 KB
Oversized
5
Wasted
1483 KB