Performance
· 17 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.
11.11 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
19.87 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
1.62 s
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.030
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
11.11 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.
19.95 s
Page Load Progression
DPage Weight BudgetAction2.3 MB transferred, 85 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
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
FJS Execution CostAction5002ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://d1aqhv4sn5kxtx.cloudfront.net/actiontag/at.js | 874ms | 616ms | 144ms | 3rd |
| https://www.ucs.org/ | 659ms | 17ms | 5ms | 3rd |
| Unattributable | 610ms | 29ms | 0ms | 3rd |
| https://www.ucs.org/tm/ | 601ms | 497ms | 91ms | 3rd |
| https://www.ucs.org/tm/?id=G-VB9DKE4V36&cx=c>m=4e64k0h1 | 509ms | 428ms | 76ms | 3rd |
| https://cdn.optimizely.com/js/3747760300.js | 480ms | 406ms | 40ms | 3rd |
| https://www.ucs.org/tm/gtd?id=AW-1071979118&cx=c>m=4e64k0h1 | 305ms | 238ms | 64ms | 3rd |
| https://www.ucs.org/tm/gtd?id=DC-8188095&cx=c>m=4e64k0h1 | 272ms | 214ms | 54ms | 3rd |
| https://connect.facebook.net/en_US/fbevents.js | 194ms | 137ms | 56ms | 3rd |
| https://connect.facebook.net/signals/config/625465517575530?v=2.9.303&r=stable&domain=www.ucs.org&hme=97937018cefade17726f0472876fc101316b2ce9008a35a6a5a7977d7436151a&ex_m=104%2C205%2C154%2C22%2C72%2C73%2C145%2C68%2C67%2C11%2C162%2C90%2C16%2C138%2C127%2C39%2C75%2C78%2C134%2C159%2C164%2C8%2C4%2C5%2C7%2C6%2C3%2C91%2C101%2C165%2C170%2C219%2C62%2C186%2C187%2C55%2C276%2C30%2C74%2C231%2C230%2C229%2C23%2C33%2C103%2C61%2C10%2C63%2C97%2C98%2C99%2C105%2C130%2C31%2C29%2C132%2C133%2C129%2C128%2C155%2C76%2C158%2C156%2C157%2C50%2C60%2C123%2C15%2C161%2C45%2C263%2C264%2C262%2C26%2C27%2C28%2C48%2C146%2C77%2C112%2C18%2C20%2C44%2C40%2C42%2C41%2C83%2C92%2C96%2C110%2C144%2C147%2C46%2C111%2C24%2C21%2C119%2C69%2C36%2C149%2C148%2C150%2C141%2C139%2C25%2C35%2C59%2C109%2C160%2C70%2C17%2C152%2C114%2C81%2C66%2C19%2C85%2C86%2C116%2C84%2C136%2C135%2C34%2C278%2C293%2C212%2C201%2C202%2C200%2C296%2C288%2C52%2C213%2C107%2C131%2C80%2C121%2C54%2C47%2C49%2C113%2C120%2C126%2C58%2C64%2C151%2C115%2C37%2C32%2C53%2C56%2C100%2C163%2C1%2C124%2C14%2C122%2C12%2C2%2C57%2C93%2C65%2C118%2C89%2C88%2C166%2C167%2C94%2C95%2C9%2C125%2C102%2C51%2C142%2C87%2C79%2C71%2C117%2C106%2C43%2C143%2C0%2C82%2C137%2C140%2C153%2C38%2C108%2C13%2C168 | 163ms | 127ms | 25ms | 3rd |
Showing top 10 of 14 scripts
FJS BundlesAction20 scripts, 691 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://d1aqhv4sn5kxtx.cloudfront.net/actiontag/at.js | 270 KB | 194 KB (72%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-NB5C4Q | 178 KB | 114 KB (64%) | ✓ | 3rd |
| https://www.ucs.org/tm/ | 186 KB | 76 KB (41%) | ✓ | 3rd |
| https://www.ucs.org/tm/?id=G-VB9DKE4V36&cx=c>m=4e64k0h1 | 181 KB | 69 KB (38%) | ✓ | 3rd |
| https://www.ucs.org/tm/gtd?id=DC-8188095&cx=c>m=4e64k0h1 | 135 KB | 68 KB (50%) | ✓ | 3rd |
| https://www.ucs.org/tm/gtd?id=AW-1071979118&cx=c>m=4e64k0h1 | 150 KB | 67 KB (44%) | ✓ | 3rd |
| https://cdn.optimizely.com/js/3747760300.js | 92 KB | 43 KB (47%) | ✓ | 3rd |
| https://connect.facebook.net/en_US/fbevents.js | 97 KB | 34 KB (36%) | ✓ | 3rd |
| https://js.verygoodvault.com/vgs-collect/2.18.4/vgs-collect.js | 44 KB | 26 KB (61%) | ✓ | 3rd |
| https://bat.bing.com/bat.js | 15 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 InventoryAction85 resources · 2.3 MB · 691 KB savings availableFIX
~690.8 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 85 resources | 2.3 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction23 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.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
A+Text CompressionAll text resources are compressedPASS
A+Font Loading7 fonts (225 KB)PASS
Web fonts
7
225 KB total
Render-blocking
0
of 7
Dominant font-display
swap
Most common across fonts
Font loading timeline
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 Hints2 hints, 0 missing preconnectsPASS
Current Resource Hints
2 resource hints configured
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
A+Third-Party ResourcesNo third-party resources 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 Waterfall85 requests over 2916msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
d1aqhv4sn5kxtx.cloudfront.net d1aqhv4sn5kxtx.cloudfront.net | Other | 874ms | 270 KB | 72% | €15/mo | Costly |
www.ucs.org www.ucs.org | Other | 659ms | 31 KB | — | €11/mo | Costly |
Unattributable Unattributable | Other | 610ms | 0 KB | — | €11/mo | Costly |
www.ucs.org www.ucs.org | Other | 601ms | 186 KB | 41% | €10/mo | Costly |
www.ucs.org www.ucs.org | Other | 509ms | 181 KB | 38% | €9/mo | Costly |
Optimizely cdn.optimizely.com | A/B Testing | 480ms | 92 KB | 47% | €8/mo | Costly |
www.ucs.org www.ucs.org | Other | 305ms | 150 KB | 44% | €5/mo | Costly |
www.ucs.org www.ucs.org | Other | 272ms | 135 KB | 50% | €5/mo | Costly |
Facebook Pixel connect.facebook.net | Advertising | 194ms | 97 KB | 36% | €3/mo | Optional |
Facebook Pixel connect.facebook.net | Advertising | 163ms | 45 KB | — | €3/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 113ms | 178 KB | 64% | €2/mo | Optional |
js.verygoodvault.com js.verygoodvault.com | Other | 81ms | 44 KB | 61% | €1/mo | Optional |
www.ucs.org www.ucs.org | Other | 78ms | 5 KB | — | €1/mo | Optional |
www.ucs.org www.ucs.org | Other | 64ms | 30 KB | — | €1/mo | Optional |
These scripts may cost more than they're worth
- d1aqhv4sn5kxtx.cloudfront.net adds 874ms and costs ~€15/month
- www.ucs.org adds 659ms and costs ~€11/month
- Unattributable adds 610ms and costs ~€11/month
- www.ucs.org adds 601ms and costs ~€10/month
- www.ucs.org adds 509ms and costs ~€9/month
- Optimizely adds 480ms and costs ~€8/month
- www.ucs.org adds 305ms and costs ~€5/month
- www.ucs.org adds 272ms and costs ~€5/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
d1aqhv4sn5kxtx.cloudfront.net takes 874ms 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
72% of d1aqhv4sn5kxtx.cloudfront.net'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
www.ucs.org takes 659ms 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 610ms 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.ucs.org takes 601ms 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.ucs.org takes 509ms 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
Optimizely takes 480ms 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.ucs.org takes 305ms 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.ucs.org takes 272ms 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
50% of www.ucs.org'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
64% 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
61% of js.verygoodvault.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