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.
909 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.30 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
238 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.070
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
1.05 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.
4.13 s
Page Load Progression
437 ms
874 ms 1.3 s
1.7 s
2.2 s
2.6 s
3.1 s
3.5 sFPage Weight BudgetAction3.1 MB transferred, 121 requestsFIX
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
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
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 BundlesAction38 scripts, 532 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=4e64k1h1 | 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-732825175&cx=c>m=4e64k1h1 | 144 KB | 58 KB (40%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-790909273&cx=c>m=4e64k1h1 | 143 KB | 57 KB (40%) | ✓ | 3rd |
| https://analytics.tiktok.com/i18n/pixel/static/main.MWE0ZWQ3ZWQwMQ.js | 110 KB | 56 KB (52%) | ✓ | 3rd |
| https://cdn.optimizely.com/js/24344740158.js | 90 KB | 40 KB (44%) | ✓ | 3rd |
| https://connect.facebook.net/en_US/fbevents.js | 97 KB | 33 KB (34%) | ✓ | 3rd |
| https://script.hotjar.com/modules.6a0f3932cb1341a35c18.js | 57 KB | 24 KB (43%) | ✓ | 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 InventoryAction121 resources · 3.1 MB · 532 KB savings availableFIX
~532.2 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 121 resources | 3.1 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
BImage Optimization46 images, 0 KB saveableREVIEW
Set explicit width and height to prevent CLS.
Performance issues directly impact user engagement and conversion rates.
CJS Execution CostAction1359ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| Unattributable | 196ms | 4ms | 0ms | 3rd |
| https://www.brennancenter.org/ | 182ms | 5ms | 1ms | 3rd |
| https://script.hotjar.com/modules.6a0f3932cb1341a35c18.js | 170ms | 148ms | 13ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-5SNMJ8W | 131ms | 101ms | 27ms | 3rd |
| https://cdn.optimizely.com/js/24344740158.js | 106ms | 83ms | 10ms | 3rd |
| https://analytics.tiktok.com/i18n/pixel/static/main.MWE0ZWQ3ZWQwMQ.js | 100ms | 79ms | 19ms | 3rd |
| https://www.brennancenter.org/sites/default/files/js/js_1ese3-0azrCQn1bkaOoj2yiaYcvuMAPSara6x1V85jc.js?scope=footer&delta=5&language=en&theme=bcj&include=eJyNj1FuxCAMRC8UNkdCDpkQNoCR7aTdnr5Eqiq1ynb7g4bnp5E9hfuYESk8nAZJzXSYOtKVBHJGvyI3yNjmxeVUN2ckETYEFoyBS-OKanrrqnMLyHbB7AJX6_js5Jz_Kdsb9_zKNm4p6LW0gmaIU5CE9VrZ8HAFqhTxpKTiTTPMzqIU696utXPm9uYWlvLMMHyt9IdQUHc3Q7d-2Cut8JQyrq0DYilQdkeawQNIH16g3dF0wKdyXjx2kj76PguzVbZOvtMtCu_NT5nD5o9E_q5DZI4Z3iiOsT-__ze60_tPWD4B4cTifA | 95ms | 37ms | 3ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-732825175&cx=c>m=4e64k1h1 | 94ms | 67ms | 15ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-18V2PKPLTH&cx=c>m=4e64k1h1 | 93ms | 75ms | 17ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-790909273&cx=c>m=4e64k1h1 | 83ms | 68ms | 14ms | 3rd |
Showing top 10 of 12 scripts
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
Network Waterfall121 requests over 4112msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Unattributable Unattributable | Other | 196ms | 0 KB | — | €3/mo | Optional |
www.brennancenter.org www.brennancenter.org | Other | 182ms | 30 KB | — | €3/mo | Optional |
Hotjar script.hotjar.com | Session Replay | 170ms | 57 KB | 43% | €3/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 131ms | 167 KB | 38% | €2/mo | Optional |
Optimizely cdn.optimizely.com | A/B Testing | 106ms | 90 KB | 44% | €2/mo | Optional |
analytics.tiktok.com analytics.tiktok.com | Other | 100ms | 110 KB | 52% | €2/mo | Optional |
www.brennancenter.org www.brennancenter.org | Other | 95ms | 19 KB | — | €2/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 94ms | 144 KB | 40% | €2/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 93ms | 167 KB | 40% | €2/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 83ms | 143 KB | 40% | €1/mo | Optional |
www.brennancenter.org www.brennancenter.org | Other | 56ms | 30 KB | 69% | €1/mo | Optional |
Facebook Pixel connect.facebook.net | Advertising | 52ms | 48 KB | — | €1/mo | Optional |
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
52% 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
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