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.
3.90 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
13.53 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
926 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.000
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
6.41 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.
13.78 s
Page Load Progression
FPage Weight BudgetAction5.4 MB transferred, 43 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
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
DJS Execution CostAction3376ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.genome.gov/sites/default/files/js/js_xi0FtGdjW2Z6VR7E4ps29cMkIygxI-vuQpt3k_8ypz4.js?scope=footer&delta=0&language=en&theme=nhgri&include=eJxljkEOgzAMBD8UmidZBkwwcmwUJ1B4fZEKl_a2O1qtBt2pAutCQ7USF3-tzWcYTCtphZ5EbAeeoEelEvBvXimvMPEbFLcwFDwPSik-ISSzJASoKEflweMvCJzXYhuNkJtUBie5viNnDzqnwnG6VHAnt0wPaSLdiok6Fx4vqy9OYj3KXRTVEopQOW5yttJ3kzUdsbLpB2MdYl8 | 1152ms | 342ms | 180ms | 3rd |
| Unattributable | 481ms | 93ms | 0ms | 3rd |
| https://www.genome.gov/ | 332ms | 5ms | 1ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-CSLL4ZEK4L | 291ms | 231ms | 59ms | 3rd |
| https://www.genome.gov/sites/default/files/google_analytics/gtag.js?tdw9db | 237ms | 174ms | 49ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-1GVMC3FXSC&cx=c>m=4e64h1 | 211ms | 158ms | 52ms | 3rd |
| https://www.genome.gov/sites/default/files/js/js_wY7SbSc8raFRw1fRnmuVtinauFDQqI3EBpM2ZlZ-Jrw.js?scope=footer&delta=2&language=en&theme=nhgri&include=eJxljkEOgzAMBD8UmidZBkwwcmwUJ1B4fZEKl_a2O1qtBt2pAutCQ7USF3-tzWcYTCtphZ5EbAeeoEelEvBvXimvMPEbFLcwFDwPSik-ISSzJASoKEflweMvCJzXYhuNkJtUBie5viNnDzqnwnG6VHAnt0wPaSLdiok6Fx4vqy9OYj3KXRTVEopQOW5yttJ3kzUdsbLpB2MdYl8 | 202ms | 85ms | 59ms | 3rd |
| https://code.jquery.com/ui/1.12.1/jquery-ui.js | 131ms | 52ms | 78ms | 3rd |
| https://www.genome.gov/sites/default/files/css/css_S9fxr0VKT9XswDa4m5Lk9YATdxRc8X_jIkStpGRT9KQ.css?delta=1&language=en&theme=nhgri&include=eJyFkFFywzAIRC9kW0fS4AhJdJDQgJQ0PX3t1Gk-4k4_2X3LLIAZdk_1Ay9d1F3MlkAx-ivhbYJ3M7GswL6AJqpnQJaCDRL6SJ--Y2n_QWhnhGITo05SvWVQ9OvoXeop29O-59TJpOGI_s0o_q5_tI6i_tlwotJUrhh8GdzJG_IWdVRsqjkpuSi1ww1t45_KYJ737GxMAfWQfz53DBWqJGBGvR_K19B1jjJqgP3qqYFCUmjZXNDRgJeXsozaxspkGcNkd9ve7FYw_AY3VbZ9 | 108ms | 0ms | 0ms | 3rd |
| https://dap.digitalgov.gov/web-vitals/dist/web-vitals.attribution.iife.js | 97ms | 93ms | 2ms | 3rd |
Showing top 10 of 12 scripts
FJS BundlesAction11 scripts, 500 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtag/js?id=G-CSLL4ZEK4L&cx=c>m=4e64h1 | 147 KB | 106 KB (72%) | ✓ | 3rd |
| https://code.jquery.com/ui/1.12.1/jquery-ui.js | 122 KB | 89 KB (84%) | ✗ | 3rd |
| https://www.genome.gov/sites/default/files/js/js_wY7SbSc8raFRw1fRnmuVtinauFDQqI3EBpM2ZlZ-Jrw.js?scope=footer&delta=2&language=en&theme=nhgri&include=eJxljkEOgzAMBD8UmidZBkwwcmwUJ1B4fZEKl_a2O1qtBt2pAutCQ7USF3-tzWcYTCtphZ5EbAeeoEelEvBvXimvMPEbFLcwFDwPSik-ISSzJASoKEflweMvCJzXYhuNkJtUBie5viNnDzqnwnG6VHAnt0wPaSLdiok6Fx4vqy9OYj3KXRTVEopQOW5yttJ3kzUdsbLpB2MdYl8 | 110 KB | 87 KB (79%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-CSLL4ZEK4L | 147 KB | 63 KB (43%) | ✓ | 3rd |
| https://www.genome.gov/sites/default/files/google_analytics/gtag.js?tdw9db | 123 KB | 61 KB (50%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-1GVMC3FXSC&cx=c>m=4e64h1 | 149 KB | 61 KB (41%) | ✓ | 3rd |
| https://www.genome.gov/sites/default/files/js/js_xi0FtGdjW2Z6VR7E4ps29cMkIygxI-vuQpt3k_8ypz4.js?scope=footer&delta=0&language=en&theme=nhgri&include=eJxljkEOgzAMBD8UmidZBkwwcmwUJ1B4fZEKl_a2O1qtBt2pAutCQ7USF3-tzWcYTCtphZ5EbAeeoEelEvBvXimvMPEbFLcwFDwPSik-ISSzJASoKEflweMvCJzXYhuNkJtUBie5viNnDzqnwnG6VHAnt0wPaSLdiok6Fx4vqy9OYj3KXRTVEopQOW5yttJ3kzUdsbLpB2MdYl8 | 455 KB | 34 KB (7%) | ✓ | 3rd |
| https://script.crazyegg.com/pages/scripts/0097/2751.js | 0 KB | — | ✓ | 3rd |
| https://dap.digitalgov.gov/Universal-Federated-Analytics-Min.js?agency=HHS&subagency=NIH | 9 KB | — | ✓ | 3rd |
| https://www.google-analytics.com/analytics.js | 21 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 InventoryAction43 resources · 5.4 MB · 500 KB savings availableFIX
~499.5 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 43 resources | 5.4 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
BImage Optimization21 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
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 Loading1 fonts (42 KB)PASS
Web fonts
1
42 KB total
Render-blocking
0
of 1
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 Waterfall43 requests over 1004msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.genome.gov www.genome.gov | Other | 1152ms | 455 KB | 7% | $15/mo | Costly |
Unattributable Unattributable | Other | 481ms | 0 KB | — | $6/mo | Costly |
www.genome.gov www.genome.gov | Other | 332ms | 40 KB | — | $4/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 291ms | 147 KB | 43% | $4/mo | Costly |
www.genome.gov www.genome.gov | Other | 237ms | 123 KB | 50% | $3/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 211ms | 149 KB | 41% | $3/mo | Costly |
www.genome.gov www.genome.gov | Other | 202ms | 110 KB | 79% | $3/mo | Costly |
code.jquery.com code.jquery.com | Other | 131ms | 122 KB | 84% | $2/mo | Optional |
www.genome.gov www.genome.gov | Other | 108ms | 82 KB | — | $1/mo | Optional |
dap.digitalgov.gov dap.digitalgov.gov | Other | 97ms | 4 KB | — | $1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 83ms | 147 KB | 72% | $1/mo | Optional |
Google Analytics www.google-analytics.com | Analytics | 50ms | 21 KB | — | $1/mo | Optional |
These scripts may cost more than they're worth
- www.genome.gov adds 1152ms and costs ~$15/month
- Unattributable adds 481ms and costs ~$6/month
- www.genome.gov adds 332ms and costs ~$4/month
- Google Tag Manager adds 291ms and costs ~$4/month
- www.genome.gov adds 237ms and costs ~$3/month
- Google Tag Manager adds 211ms and costs ~$3/month
- www.genome.gov adds 202ms and costs ~$3/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.genome.gov takes 1152ms 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 481ms 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.genome.gov takes 332ms 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 291ms 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.genome.gov takes 237ms 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 211ms 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.genome.gov takes 202ms 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
79% of www.genome.gov'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
84% of code.jquery.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
72% 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