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.
1.05 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.43 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
36 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.093
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
1.59 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.
4.12 s
Page Load Progression
375 ms
750 ms
1.1 s
1.5 s 1.9 s
2.2 s 2.6 s
3.0 sFPage Weight BudgetAction2.6 MB transferred, 92 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 BundlesAction20 scripts, 693 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/gtd?id=AW-1071979118&cx=c>m=4e64k0 | 150 KB | 74 KB (50%) | ✓ | 3rd |
| https://www.ucs.org/tm/ | 186 KB | 70 KB (38%) | ✓ | 3rd |
| https://www.ucs.org/tm/?id=G-VB9DKE4V36&cx=c>m=4e64k0 | 181 KB | 70 KB (38%) | ✓ | 3rd |
| https://www.ucs.org/tm/gtd?id=DC-8188095&cx=c>m=4e64k0 | 135 KB | 67 KB (50%) | ✓ | 3rd |
| https://cdn.optimizely.com/js/3747760300.js | 92 KB | 43 KB (47%) | ✓ | 3rd |
| https://connect.facebook.net/en_US/fbevents.js | 97 KB | 35 KB (36%) | ✓ | 3rd |
| https://js.verygoodvault.com/vgs-collect/2.18.4/vgs-collect.js | 44 KB | 26 KB (61%) | ✓ | 3rd |
| https://www.ucs.org/themes/custom/ucstheme/js/theme.js?v=1.x | 5 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 InventoryAction92 resources · 2.6 MB · 693 KB savings availableFIX
~692.8 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 92 resources | 2.6 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction27 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
BJS Execution Cost806ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.ucs.org/ | 229ms | 4ms | 1ms | 3rd |
| https://d1aqhv4sn5kxtx.cloudfront.net/actiontag/at.js | 145ms | 111ms | 24ms | 3rd |
| https://www.ucs.org/tm/ | 124ms | 94ms | 15ms | 3rd |
| https://www.ucs.org/tm/?id=G-VB9DKE4V36&cx=c>m=4e64k0 | 86ms | 72ms | 13ms | 3rd |
| Unattributable | 85ms | 2ms | 0ms | 3rd |
| https://cdn.optimizely.com/js/3747760300.js | 79ms | 66ms | 7ms | 3rd |
| https://www.ucs.org/tm/gtd?id=AW-1071979118&cx=c>m=4e64k0 | 58ms | 29ms | 9ms | 3rd |
A+Text CompressionAll text resources are compressedPASS
A+Font Loading7 fonts (224 KB)PASS
Web fonts
7
224 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 HintsNo optimization neededPASS
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
This site is hosted on green energy infrastructure
Provider: Cloudflare
Network Waterfall92 requests over 2577msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.ucs.org www.ucs.org | Other | 229ms | 31 KB | — | €4/mo | Costly |
d1aqhv4sn5kxtx.cloudfront.net d1aqhv4sn5kxtx.cloudfront.net | Other | 145ms | 270 KB | 72% | €3/mo | Optional |
www.ucs.org www.ucs.org | Other | 124ms | 186 KB | 38% | €2/mo | Optional |
www.ucs.org www.ucs.org | Other | 86ms | 181 KB | 38% | €1/mo | Optional |
Unattributable Unattributable | Other | 85ms | 0 KB | — | €1/mo | Optional |
Optimizely cdn.optimizely.com | A/B Testing | 79ms | 92 KB | 47% | €1/mo | Optional |
www.ucs.org www.ucs.org | Other | 58ms | 150 KB | 50% | €1/mo | Optional |
These scripts may cost more than they're worth
- www.ucs.org adds 229ms 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
www.ucs.org takes 229ms 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