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.
4.26 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
21.08 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
2.18 s
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.006
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
7.12 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.
22.14 s
Page Load Progression
745 ms 1.5 s 2.2 s
3.0 s 3.7 s 4.5 s 5.2 s
6.0 sFPage Weight BudgetAction2.6 MB transferred, 101 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
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
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
FJS Execution CostAction5293ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| Unattributable | 723ms | 109ms | 0ms | 3rd |
| https://www.brennancenter.org/sites/default/files/js/js_Oe3_K7sAsWnpXAZDFrbQobSmXxNM9to5m1YY_-nKs40.js?scope=footer&delta=1&language=en&theme=bcj&include=eJyNj1FuxCAMRC8UNkdCDpkQNoCR7aTdnr5Eqiq1ynb7g4bnp5E9hfuYESk8nAZJzXSYOtKVBHJGvyI3yNjmxeVUN2ckETYEFoyBS-OKanrrqnMLyHbB7AJX6_js5Jz_Kdsb9_zKNm4p6LW0gmaIU5CE9VrZ8HAFqhTxpKTiTTPMzqIU696utXPm9uYWlvLMMHyt9IdQUHc3Q7d-2Cut8JQyrq0DYilQdkeawQNIH16g3dF0wKdyXjx2kj76PguzVbZOvtMtCu_NT5nD5o9E_q5DZI4Z3iiOsT-__ze60_tPWD4B4cTifA | 568ms | 221ms | 13ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-5SNMJ8W | 532ms | 430ms | 84ms | 3rd |
| https://cdn.optimizely.com/js/24344740158.js | 405ms | 316ms | 42ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-18V2PKPLTH&cx=c>m=4e64k1 | 381ms | 305ms | 72ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-732825175&cx=c>m=4e64k1 | 350ms | 288ms | 58ms | 3rd |
| https://www.brennancenter.org/ | 326ms | 13ms | 3ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-790909273&cx=c>m=4e64k1 | 320ms | 262ms | 54ms | 3rd |
| https://analytics.tiktok.com/i18n/pixel/static/main.MWE0ZWQ3ZWQwMQ.js | 316ms | 241ms | 69ms | 3rd |
| https://script.hotjar.com/modules.6a0f3932cb1341a35c18.js | 212ms | 176ms | 31ms | 3rd |
Showing top 10 of 20 scripts
FJS BundlesAction38 scripts, 542 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://analytics.tiktok.com/i18n/pixel/static/main.MWE0ZWQ3ZWQwOQ.js | 121 KB | 92 KB (77%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-18V2PKPLTH&cx=c>m=4e64k1 | 167 KB | 67 KB (40%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-5SNMJ8W | 167 KB | 64 KB (38%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-790909273&cx=c>m=4e64k1 | 143 KB | 58 KB (40%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-732825175&cx=c>m=4e64k1 | 144 KB | 57 KB (39%) | ✓ | 3rd |
| https://analytics.tiktok.com/i18n/pixel/static/main.MWE0ZWQ3ZWQwMQ.js | 110 KB | 55 KB (50%) | ✓ | 3rd |
| https://cdn.optimizely.com/js/24344740158.js | 90 KB | 40 KB (44%) | ✓ | 3rd |
| https://script.hotjar.com/modules.6a0f3932cb1341a35c18.js | 57 KB | 36 KB (65%) | ✓ | 3rd |
| https://connect.facebook.net/en_US/fbevents.js | 97 KB | 32 KB (34%) | ✓ | 3rd |
| https://www.brennancenter.org/sites/default/files/js/js_Oe3_K7sAsWnpXAZDFrbQobSmXxNM9to5m1YY_-nKs40.js?scope=footer&delta=1&language=en&theme=bcj&include=eJyNj1FuxCAMRC8UNkdCDpkQNoCR7aTdnr5Eqiq1ynb7g4bnp5E9hfuYESk8nAZJzXSYOtKVBHJGvyI3yNjmxeVUN2ckETYEFoyBS-OKanrrqnMLyHbB7AJX6_js5Jz_Kdsb9_zKNm4p6LW0gmaIU5CE9VrZ8HAFqhTxpKTiTTPMzqIU696utXPm9uYWlvLMMHyt9IdQUHc3Q7d-2Cut8JQyrq0DYilQdkeawQNIH16g3dF0wKdyXjx2kj76PguzVbZOvtMtCu_NT5nD5o9E_q5DZI4Z3iiOsT-__ze60_tPWD4B4cTifA | 30 KB | 21 KB (69%) | ✓ | 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 InventoryAction101 resources · 2.6 MB · 542 KB savings availableFIX
~541.6 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 101 resources | 2.6 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
BImage Optimization28 images, 0 KB saveableREVIEW
Set explicit width and height to prevent CLS.
Performance issues directly impact user engagement and conversion rates.
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 (119 KB)PASS
Web fonts
4
119 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
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
A+Third-Party ResourcesNo third-party resources detectedPASS
Network Waterfall101 requests over 4093msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Unattributable Unattributable | Other | 723ms | 0 KB | — | €13/mo | Costly |
www.brennancenter.org www.brennancenter.org | Other | 568ms | 30 KB | 69% | €10/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 532ms | 167 KB | 38% | €9/mo | Costly |
Optimizely cdn.optimizely.com | A/B Testing | 405ms | 90 KB | 44% | €7/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 381ms | 167 KB | 40% | €7/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 350ms | 144 KB | 39% | €6/mo | Costly |
www.brennancenter.org www.brennancenter.org | Other | 326ms | 30 KB | — | €6/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 320ms | 143 KB | 40% | €6/mo | Costly |
analytics.tiktok.com analytics.tiktok.com | Other | 316ms | 110 KB | 50% | €5/mo | Costly |
Hotjar script.hotjar.com | Session Replay | 212ms | 57 KB | 65% | €4/mo | Costly |
Facebook Pixel connect.facebook.net | Advertising | 194ms | 48 KB | — | €3/mo | Optional |
Facebook Pixel connect.facebook.net | Advertising | 183ms | 97 KB | 34% | €3/mo | Optional |
analytics.tiktok.com analytics.tiktok.com | Other | 158ms | 121 KB | 77% | €3/mo | Optional |
www.brennancenter.org www.brennancenter.org | Other | 133ms | 20 KB | — | €2/mo | Optional |
loader.wisepops.com loader.wisepops.com | Other | 122ms | 0 KB | — | €2/mo | Optional |
LinkedIn Insight snap.licdn.com | Advertising | 109ms | 19 KB | — | €2/mo | Optional |
Twitter/X Pixel static.ads-twitter.com | Advertising | 90ms | 13 KB | — | €2/mo | Optional |
analytics.tiktok.com analytics.tiktok.com | Other | 61ms | 39 KB | — | €1/mo | Optional |
www.redditstatic.com www.redditstatic.com | Other | 57ms | 19 KB | — | €1/mo | Optional |
www.brennancenter.org www.brennancenter.org | Other | 52ms | 32 KB | 65% | €1/mo | Optional |
These scripts may cost more than they're worth
- Unattributable adds 723ms and costs ~€13/month
- www.brennancenter.org adds 568ms and costs ~€10/month
- Google Tag Manager adds 532ms and costs ~€9/month
- Optimizely adds 405ms and costs ~€7/month
- Google Tag Manager adds 381ms and costs ~€7/month
- Google Tag Manager adds 350ms and costs ~€6/month
- www.brennancenter.org adds 326ms and costs ~€6/month
- Google Tag Manager adds 320ms and costs ~€6/month
- analytics.tiktok.com adds 316ms and costs ~€5/month
- Hotjar adds 212ms 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
Unattributable takes 723ms 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.brennancenter.org takes 568ms 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
69% of www.brennancenter.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
Google Tag Manager takes 532ms 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 405ms 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 381ms 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 350ms 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.brennancenter.org takes 326ms 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 320ms 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
analytics.tiktok.com takes 316ms 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 analytics.tiktok.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
Hotjar takes 212ms 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
65% of Hotjar'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 analytics.tiktok.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
65% of www.brennancenter.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