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.
1.96 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
2.73 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
357 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.508
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
2.70 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.
5.61 s
Page Load Progression
FPage Weight BudgetAction4.1 MB transferred, 123 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
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
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
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 Execution CostAction2966ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.ets.org/ | 533ms | 28ms | 2ms | 3rd |
| Unattributable | 446ms | 74ms | 0ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-KPNMN62 | 274ms | 206ms | 36ms | 3rd |
| https://www.ets.org/etc.clientlibs/ets/clientlibs/clientlib-marketing.lc-d7765c5acbf726fd7ab79130fcd1444b-lc.min.js | 253ms | 222ms | 8ms | 3rd |
| https://cdn.cookielaw.org/scripttemplates/202409.2.0/otBannerSdk.js | 191ms | 127ms | 20ms | 3rd |
| https://assets.anytrack.io/scripts/v0/6d3458f.js | 188ms | 166ms | 8ms | 3rd |
| https://www.ets.org/etc.clientlibs/ets/clientlibs/clientlib-dependencies.lc-6cd03945753d69e40ab90007f02916d3-lc.min.js | 127ms | 62ms | 62ms | 3rd |
| https://scripts.clarity.ms/0.8.59/clarity.js | 105ms | 89ms | 6ms | 3rd |
| https://analytics.tiktok.com/i18n/pixel/static/main.MWE0ZWQ3ZWQwMQ.js | 104ms | 82ms | 20ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-X4K1GDGMNJ&cx=c>m=4e64h1h1 | 102ms | 76ms | 25ms | 3rd |
Showing top 10 of 18 scripts
FJS BundlesAction72 scripts, 1.5 MB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.ets.org/etc.clientlibs/ets/clientlibs/clientlib-dependencies.lc-6cd03945753d69e40ab90007f02916d3-lc.min.js | 358 KB | 282 KB (79%) | ✗ | 3rd |
| https://www.googletagmanager.com/gtag/destination?id=G-LSPK6N3LCN&cx=c>m=4e64h1h1 | 172 KB | 90 KB (52%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/destination?id=G-T2TH8KSGFZ&cx=c>m=4e64h1h1 | 175 KB | 89 KB (51%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-X4K1GDGMNJ&cx=c>m=4e64h1h1 | 169 KB | 87 KB (52%) | ✓ | 3rd |
| https://www.ets.org/etc.clientlibs/ets/clientlibs/clientlib-dynamic-modules/resources/2033-7140ca798143be17c2e1.js | 0 KB | 84 KB (69%) | ✓ | 3rd |
| https://www.ets.org/etc.clientlibs/ets/clientlibs/clientlib-dynamic-modules/resources/2033-7140ca798143be17c2e1.js | 39 KB | 84 KB (69%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-961899722&cx=c>m=4e64h1h1 | 144 KB | 80 KB (55%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-819758456&cx=c>m=4e64h1h1 | 147 KB | 79 KB (54%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/destination?id=AW-11040439592&cx=c>m=4e64h1h1 | 138 KB | 78 KB (57%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-10977752788&cx=c>m=4e64h1h1 | 138 KB | 78 KB (56%) | ✓ | 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 InventoryAction123 resources · 4.1 MB · 1.5 MB savings availableFIX
~1.5 MiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 123 resources | 4.1 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.
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
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
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
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 Loading4 fonts (254 KB)PASS
Web fonts
4
254 KB total
Render-blocking
0
of 4
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
Network Waterfall123 requests over 4651msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.ets.org www.ets.org | Other | 533ms | 22 KB | — | $10/mo | Costly |
Unattributable Unattributable | Other | 446ms | 0 KB | — | $8/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 274ms | 209 KB | 29% | $5/mo | Costly |
www.ets.org www.ets.org | Other | 253ms | 50 KB | — | $5/mo | Costly |
OneTrust cdn.cookielaw.org | Consent | 191ms | 112 KB | 54% | $4/mo | Essential |
assets.anytrack.io assets.anytrack.io | Other | 188ms | 72 KB | 44% | $4/mo | Optional |
www.ets.org www.ets.org | Other | 127ms | 358 KB | 79% | $2/mo | Optional |
Microsoft Clarity scripts.clarity.ms | Session Replay | 105ms | 26 KB | — | $2/mo | Optional |
analytics.tiktok.com analytics.tiktok.com | Other | 104ms | 110 KB | 50% | $2/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 102ms | 169 KB | 52% | $2/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 97ms | 172 KB | 52% | $2/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 93ms | 175 KB | 51% | $2/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 87ms | 147 KB | 54% | $2/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 85ms | 138 KB | 56% | $2/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 82ms | 144 KB | 55% | $2/mo | Optional |
Facebook Pixel connect.facebook.net | Advertising | 68ms | 48 KB | — | $1/mo | Optional |
www.ets.org www.ets.org | Other | 66ms | 33 KB | — | $1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 64ms | 138 KB | 57% | $1/mo | Optional |
These scripts may cost more than they're worth
- www.ets.org adds 533ms and costs ~$10/month
- Unattributable adds 446ms and costs ~$8/month
- Google Tag Manager adds 274ms and costs ~$5/month
- www.ets.org adds 253ms 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
www.ets.org takes 533ms 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 446ms 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
Google Tag Manager takes 274ms 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.ets.org takes 253ms 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
54% of OneTrust'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
79% of www.ets.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
52% 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
52% 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
51% 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
54% 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
56% 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
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
57% 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