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.
3.65 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
7.85 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
1.80 s
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.
4.33 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.
15.13 s
Page Load Progression
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
FJS Execution CostAction4461ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.archives.gov/files/js/js_XexEZhbTmj1BHeajKr2rPfyR8Y68f4rm0Nv3Vj5_dSI.js | 1356ms | 1283ms | 11ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-WLMC86 | 514ms | 372ms | 91ms | 3rd |
| Unattributable | 510ms | 7ms | 0ms | 3rd |
| https://www.archives.gov/ | 295ms | 11ms | 4ms | 3rd |
| https://www.google-analytics.com/analytics.js | 285ms | 260ms | 4ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-JSGC9Q8KRE&cx=c>m=4e64h1 | 267ms | 227ms | 37ms | 3rd |
| https://script.crazyegg.com/pages/versioned/common-scripts/4ce8c7df8d425cc50464576824ed91eb.js | 266ms | 241ms | 11ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-Z0BESEZFL2&cx=c>m=4e64h1 | 258ms | 214ms | 41ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-NPRSVNG84W&cx=c&_slc=1 | 223ms | 186ms | 36ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-0KHCNR6KSZ&cx=c>m=4e64h1 | 219ms | 179ms | 37ms | 3rd |
Showing top 10 of 14 scripts
FJS BundlesAction22 scripts, 555 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://www.googletagmanager.com/gtag/js?id=G-0KHCNR6KSZ&cx=c>m=4e64h1 | 158 KB | 67 KB (42%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-Z0BESEZFL2&cx=c>m=4e64h1 | 160 KB | 65 KB (41%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-NPRSVNG84W&cx=c&_slc=1 | 148 KB | 65 KB (44%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-JSGC9Q8KRE&cx=c>m=4e64h1 | 157 KB | 64 KB (41%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-CSLL4ZEK4L | 147 KB | 62 KB (42%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-WLMC86 | 165 KB | 50 KB (30%) | ✓ | 3rd |
| https://www.archives.gov/files/js/js_lBihdeJYQAyc3cvG-bzBMa_r_tJJ39unyQ2vVwtPQ9Y.js | 64 KB | 46 KB (73%) | ✗ | 3rd |
| https://script.crazyegg.com/pages/versioned/common-scripts/4ce8c7df8d425cc50464576824ed91eb.js | 55 KB | 30 KB (54%) | ✓ | 3rd |
| https://static.addtoany.com/menu/page.js | 2 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 InventoryAction91 resources · 1.9 MB · 555 KB savings availableFIX
~555.4 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 91 resources | 1.9 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CPage Weight BudgetAction1.9 MB transferred, 91 requestsREVIEW
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
BImage Optimization13 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 Loading5 fonts (154 KB)PASS
Web fonts
5
154 KB total
Render-blocking
0
of 5
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 Waterfall91 requests over 2376msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.archives.gov www.archives.gov | Other | 1356ms | 46 KB | — | $8/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 514ms | 165 KB | 30% | $3/mo | Costly |
Unattributable Unattributable | Other | 510ms | 0 KB | — | $3/mo | Costly |
www.archives.gov www.archives.gov | Other | 295ms | 8 KB | — | $2/mo | Costly |
Google Analytics www.google-analytics.com | Analytics | 285ms | 21 KB | — | $2/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 267ms | 157 KB | 41% | $2/mo | Costly |
script.crazyegg.com script.crazyegg.com | Other | 266ms | 55 KB | 54% | $2/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 258ms | 160 KB | 41% | $1/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 223ms | 148 KB | 44% | $1/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 219ms | 158 KB | 42% | $1/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 85ms | 147 KB | 42% | $0/mo | Optional |
dap.digitalgov.gov dap.digitalgov.gov | Other | 70ms | 4 KB | — | $0/mo | Optional |
script.crazyegg.com script.crazyegg.com | Other | 57ms | 23 KB | — | $0/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 57ms | 147 KB | 72% | $0/mo | Optional |
These scripts may cost more than they're worth
- www.archives.gov adds 1356ms and costs ~$8/month
- Google Tag Manager adds 514ms and costs ~$3/month
- Unattributable adds 510ms and costs ~$3/month
- www.archives.gov adds 295ms and costs ~$2/month
- Google Analytics adds 285ms and costs ~$2/month
- Google Tag Manager adds 267ms and costs ~$2/month
- script.crazyegg.com adds 266ms and costs ~$2/month
- Google Tag Manager adds 258ms and costs ~$1/month
- Google Tag Manager adds 223ms and costs ~$1/month
- Google Tag Manager adds 219ms and costs ~$1/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.archives.gov takes 1356ms 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 514ms 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 510ms 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.archives.gov takes 295ms 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 Analytics takes 285ms 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 267ms 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
script.crazyegg.com takes 266ms 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 script.crazyegg.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
Google Tag Manager takes 258ms 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 223ms 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 219ms 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 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