Performance
· 15 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.
942 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.21 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
204 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.
1.21 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.
3.96 s
Page Load Progression
FPage Weight BudgetAction3.0 MB transferred, 151 requestsFIX
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
Subset fonts to include only used characters, or switch to system font stacks.
Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).
Source: web.dev font loading
Remove unused CSS rules with tools like PurgeCSS to reduce stylesheet size.
CSS bundle is large — purge unused styles (PurgeCSS, Tailwind JIT) to reduce CSS payload.
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
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
DJS BundlesAction95 scripts, 452 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://fast.wistia.com/assets/external/engines/hls_video.js@379dc59f3883ecbd8a4ec99277538cfd8c619ee8 | 159 KB | 122 KB (77%) | ✓ | 3rd |
| https://acsbapp.com/apps/app/dist/js/app.js | 222 KB | 114 KB (53%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-PBJ84RQ | 186 KB | 81 KB (44%) | ✓ | 3rd |
| https://fast.wistia.com/assets/external/E-v1.js | 162 KB | 71 KB (44%) | ✓ | 3rd |
| https://consent.trustarc.com/asset/notice.js/v/v1.7-1729 | 36 KB | 22 KB (60%) | ✓ | 3rd |
| https://browser.sentry-cdn.com/9.6.1/bundle.min.js | 25 KB | 21 KB (86%) | ✓ | 3rd |
| https://static.addtoany.com/menu/modules/core.ydpp7jcu.js | 26 KB | 21 KB (82%) | ✓ | 3rd |
| https://www.ul.com/core/assets/vendor/loadjs/loadjs.min.js?v=4.3.0 | 1 KB | — | ✓ | 3rd |
| https://www.ul.com/profiles/custom/ul_enterprise_profile/themes/custom/ul_enterprise_theme/js/mobile_menu.js?tdab90 | 2 KB | — | ✓ | 3rd |
| https://www.ul.com/core/misc/drupal.js?v=10.6.2 | 7 KB | — | ✗ | 3rd |
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
FPage Weight InventoryAction151 resources · 3.0 MB · 452 KB savings availableFIX
~452.3 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 151 resources | 3.0 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction24 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
CJS Execution CostAction1499ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://fast.wistia.com/assets/external/E-v1.js | 522ms | 434ms | 23ms | 3rd |
| https://www.ul.com/ | 311ms | 14ms | 0ms | 3rd |
| Unattributable | 222ms | 19ms | 0ms | 3rd |
| https://www.ul.com/profiles/custom/ul_base_profile/themes/custom/ul_base_theme/build/scripts/app.built.js?v=10.6.2 | 199ms | 151ms | 47ms | 3rd |
| https://acsbapp.com/apps/app/dist/js/app.js | 98ms | 71ms | 14ms | 3rd |
| https://fast.wistia.com/assets/external/engines/hls_video.js@379dc59f3883ecbd8a4ec99277538cfd8c619ee8 | 78ms | 59ms | 1ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-PBJ84RQ | 70ms | 56ms | 13ms | 3rd |
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
A+Text CompressionAll text resources are compressedPASS
A+Font Loading8 fonts (273 KB)PASS
Web fonts
8
273 KB total
Render-blocking
0
of 8
Dominant font-display
swap
Most common across fonts
Font loading timeline
- 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)
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
Network Waterfall151 requests over 6292msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
fast.wistia.com fast.wistia.com | Other | 522ms | 162 KB | 44% | €9/mo | Costly |
www.ul.com www.ul.com | Other | 311ms | 38 KB | — | €5/mo | Costly |
Unattributable Unattributable | Other | 222ms | 0 KB | — | €4/mo | Costly |
www.ul.com www.ul.com | Other | 199ms | 508 KB | — | €3/mo | Optional |
acsbapp.com acsbapp.com | Other | 98ms | 222 KB | 53% | €2/mo | Optional |
fast.wistia.com fast.wistia.com | Other | 78ms | 159 KB | 77% | €1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 70ms | 186 KB | 44% | €1/mo | Optional |
These scripts may cost more than they're worth
- fast.wistia.com adds 522ms and costs ~€9/month
- www.ul.com adds 311ms and costs ~€5/month
- Unattributable adds 222ms and costs ~€4/month
100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
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
fast.wistia.com takes 522ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
www.ul.com takes 311ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Unattributable takes 222ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
53% of acsbapp.com'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
77% of fast.wistia.com'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