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Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
75
GRADE
C
FIX
3
REVIEW
3
PASS
8
INFO
2

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop
46
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
89
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
96
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
100
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

1.90 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

4.43 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

1.01 s

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.268

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

3.66 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.

34.28 s

Page Load Progression

626 ms
1.3 s
1.9 s
2.5 s
3.1 s
3.8 s
4.4 s
5.0 s
Checks
16
8 PASS 3 REVIEW 3 FIX
F
Page Weight Budget
Action
9.0 MB transferred, 125 requests
FIX
9.0 MB transferred, 125 requests
Critical::
Page weighs 16.3 MB (9.0 MB transferred)
Warning::
Images are 5.9 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 5.9 MB
Warning::
JavaScript is 2.2 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 2.2 MB
Info::
Fonts are 206 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 206 KB
Warning::
125 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 1.9 g CO2 per page load
9.0 MB / 2.4 MB budget
9.0 MB transferred
125 requests
1.9 g CO2 per page load
Images 5.9 MiB 65%
JavaScript 2.2 MiB 24%
Other 450.9 KiB 5%
Fonts 205.6 KiB 2%
CSS 140.0 KiB 2%
HTML 139.6 KiB 2%
Other 16.4 KiB 0%
Other 2.4 KiB 0%
Other 684 B 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Over budget

Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.

Why this matters

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.

Why this matters

JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.

Source: web.dev

Subset fonts to include only used characters, or switch to system font stacks.

Why this matters

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.

Why this matters

High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.

Source: web.dev

D
Third-Party Impact
Action
72% third-party, 0 ms blocking
FIX
72% third-party, 0 ms blocking
Warning::
Third-party code accounts for 72% of page weight (6.5 MiB of 9.0 MiB)
Info::
Third-party blocking time is low (0 ms)
28%
72%
First-party Third-party
F
JS Execution Cost
Action
6587ms total JS execution
FIX
6587ms total JS execution
Warning::
https://www.nasa.gov/: 3674ms CPU time
Warning::
Unattributable: 798ms CPU time
Warning::
https://www.nasa.gov/_static/??-eJyNzk0OAiEMBeALyR...: 617ms CPU time
Warning::
https://www.googletagmanager.com/gtag/js?id=G-CSLL...: 392ms CPU time
Warning::
https://www.googletagmanager.com/gtag/js?id=G-82GW...: 359ms CPU time
Info::
Third-party scripts: 2295ms (35% of total)

Main Thread Breakdown

Other 28% Script Evaluation 26% Style & Layout 19% Rendering 18% Parse HTML & CSS 4% Script Parsing & Compilation 4%
ScriptTotalScriptingParse/CompileParty
https://www.nasa.gov/3674ms41ms3ms1st
Unattributable798ms9ms0ms3rd
https://www.nasa.gov/_static/??-eJyNzk0OAiEMBeALyRCNGXRhPEsdGwbSFoXi3+nF6MKVmDSvm+81tdeTCTJRPWKxsc25Yr5/1sBBhlgW9hcyHHwGxW88JVEUtTojt4pAgVfPUzoAGYFLBzJKNZq8J+xIqrck7/zjAQ2MjyS9o2WGjKakKQA1uufd0rn1uBo3bhuftz5wvg==617ms382ms71ms1st
https://www.googletagmanager.com/gtag/js?id=G-CSLL4ZEK4L392ms346ms41ms3rd
https://www.googletagmanager.com/gtag/js?id=G-82GWVTTXCZ&cx=c&gtm=4e6411359ms299ms56ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-NLJ258M278ms208ms66ms3rd
https://www.youtube.com/s/player/f4c47414/www-widgetapi.vflset/www-widgetapi.js203ms183ms4ms3rd
https://cdn.parsely.com/keys/nasa.gov/p.js?ver=3.22.0190ms153ms18ms3rd
https://dap.digitalgov.gov/web-vitals/dist/web-vitals.attribution.iife.js74ms64ms8ms3rd
B
Image Optimization
48 images, 0 KB saveable
REVIEW
48 images, 0 KB saveable
Info::
All images are well-optimized
48 images 5.9 MB
0 oversized -0 KB
23 legacy format
0 missing dimensions CLS risk
C
JS Bundles
Action
26 scripts, 216 KB unused
REVIEW
26 scripts, 216 KB unused
Warning::
https://www.googletagmanager.com/gtag/js?id=G-82GW...: 63 KB unused (40%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-NLJ...: 61 KB unused (47%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtag/js?id=G-CSLL...: 57 KB unused (39%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.nasa.gov/_static/??-eJyNzk0OAiEMBeALyR...: 36 KB unused (57%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 216 KB
216 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.googletagmanager.com/gtag/js?id=G-82GWVTTXCZ&cx=c&gtm=4e6411158 KB63 KB (40%)✓3rd
https://www.googletagmanager.com/gtm.js?id=GTM-NLJ258M128 KB61 KB (47%)✓3rd
https://www.googletagmanager.com/gtag/js?id=G-CSLL4ZEK4L146 KB57 KB (39%)✓3rd
https://www.nasa.gov/_static/??-eJyNzk0OAiEMBeALyRCNGXRhPEsdGwbSFoXi3+nF6MKVmDSvm+81tdeTCTJRPWKxsc25Yr5/1sBBhlgW9hcyHHwGxW88JVEUtTojt4pAgVfPUzoAGYFLBzJKNZq8J+xIqrck7/zjAQ2MjyS9o2WGjKakKQA1uufd0rn1uBo3bhuftz5wvg==63 KB36 KB (57%)✓1st
https://www.youtube.com/s/player/f4c47414/player_embed_es6.vflset/en_US/base.js431 KB—✓3rd
https://static.doubleclick.net/instream/ad_status.js0 KB—✓3rd
https://www.nasa.gov/wp-content/plugins/accessibility-checker/build/frontendFixes.bundle.js?ver=1.38.04 KB—✓1st
https://www.nasa.gov/_static/??-eJyVjrEOwjAMRH+INCqodEIMSPxH4xjq1kmqOKHw96SVYIGli+U7+d5Zz5OC4BP6pCfOd/KiOwAUIUNM6aWgRxgxqikGbTKx1be4BuyVniiVyd4yVoPs9B+W76RThgOMhSuCSTSE7JMNs1ew+Pry0ZdFbgAxPVClPiKWa87O/zobaMJUnlln5WhL0iGm0orfpWTP7lS3bVM3++OhHd4L4YZp16 KB—✓1st
https://dap.digitalgov.gov/web-vitals/dist/web-vitals.attribution.iife.js4 KB—✓3rd
https://www.nasa.gov/wp-content/plugins/wp-parsely/build/loader.js?ver=ecf94842061bea03d54b2 KB—✓1st

Consider code splitting or tree shaking to reduce unused code.

Why this matters

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.

Why this matters

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.

Why this matters

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.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A+
Font Loading
7 fonts (206 KB)
PASS
7 fonts (206 KB)
Info::
7 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

7

206 KB total

Render-blocking

0

of 7

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 1.0 s 2.0 s 3.0 s 4.0 s FCP 1.9 s LCP 4.4 shttps://www.nasa.gov/wp-content/client-mu-plugins/uswds-framework/uswds/fonts/public-sans/PublicSans-Regular.woff2PublicSans-Regular.woff2 https://www.nasa.gov/wp-content/client-mu-plugins/uswds-framework/uswds/fonts/public-sans/PublicSans-Regular.woff2 — 32.1 KiB — 0 ms — font-display: swaphttps://www.nasa.gov/wp-content/client-mu-plugins/uswds-framework/uswds/fonts-split/inter/UcC73FwrK3iLTeHuS_fvQtMwCp50KnMa1ZL7.woff2UcC73FwrK3iLTeHuS_fvQtM... https://www.nasa.gov/wp-content/client-mu-plugins/uswds-framework/uswds/fonts-split/inter/UcC73FwrK3iLTeHuS_fvQtMwCp50KnMa1ZL7.woff2 — 37.4 KiB — 0 ms — font-display: swaphttps://www.nasa.gov/wp-content/client-mu-plugins/uswds-framework/uswds/fonts-split/db-mono/aFTU7PB1QTsUX8KYthqQBA.woff2aFTU7PB1QTsUX8KYthqQBA.... https://www.nasa.gov/wp-content/client-mu-plugins/uswds-framework/uswds/fonts-split/db-mono/aFTU7PB1QTsUX8KYthqQBA.woff2 — 14.4 KiB — 0 ms — font-display: swaphttps://www.nasa.gov/wp-content/client-mu-plugins/uswds-framework/uswds/fonts-split/inter/UcCO3FwrK3iLTeHuS_fvQtMwCp50KnMw2boKoduKmMEVuLyfAZ9hiA.woff2UcCO3FwrK3iLTeHuS_fvQtM... https://www.nasa.gov/wp-content/client-mu-plugins/uswds-framework/uswds/fonts-split/inter/UcCO3FwrK3iLTeHuS_fvQtMwCp50KnMw2boKoduKmMEVuLyfAZ9hiA.woff2 — 16.6 KiB — 0 ms — font-display: swaphttps://www.nasa.gov/wp-content/client-mu-plugins/uswds-framework/uswds/fonts/public-sans/PublicSans-Bold.woff2PublicSans-Bold.woff2 https://www.nasa.gov/wp-content/client-mu-plugins/uswds-framework/uswds/fonts/public-sans/PublicSans-Bold.woff2 — 32.0 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2KFO7CnqEu92Fr1ME7kSn66a... https://fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2 — 33.9 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBA.woff2KFO7CnqEu92Fr1ME7kSn66a... https://fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBA.woff2 — 39.2 KiB — 0 ms — font-display: swap
PublicSans-Regular.woff2 woff2 swap
Size 32 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
UcC73FwrK3iLTeHuS_fvQtM... woff2 swap
Size 37 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
aFTU7PB1QTsUX8KYthqQBA.... woff2 swap
Size 14 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
UcCO3FwrK3iLTeHuS_fvQtM... woff2 swap
Size 17 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
PublicSans-Bold.woff2 woff2 swap
Size 32 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
KFO7CnqEu92Fr1ME7kSn66a... woff2 swap
Size 34 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
KFO7CnqEu92Fr1ME7kSn66a... woff2 swap
Size 39 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
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 Caching
All resources properly cached
PASS
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
No render-blocking resources detected
A+
Resource Hints
4 hints, 0 missing preconnects
PASS
4 hints, 0 missing preconnects
Info::
Page uses 4 resource hint(s)

Current Resource Hints

preconnect
—
preload
3
dns-prefetch
1
prefetch
—

4 resource hints configured

A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
A
HTTP Caching
max-age=300 (5 minutes)
PASS
max-age=300 (5 minutes)
Info::
Cache-Control header is set
Got: max-age=300, must-revalidate
Info::
Effective TTL: 5 minutes (max-age=300)
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

max-age=300, must-revalidate

DirectiveValueMeaning
max-age300Cache for 5 minutes
must-revalidate—Must recheck with server after expiry
Effective TTL: 300 seconds
Network Waterfall
125 requests over 0ms
INFO

Performance analysis not available for this result.

Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
35% of JavaScript execution is third-party
First-party Third-party 2295ms · 473KB · $30/mo
Unattributable
Other
Costly
Execution 798ms
Transfer 0 KB
Monthly Cost $11/mo
Google Tag Manager
Tag Manager
Costly
Execution 392ms
Transfer 146 KB
Unused 39%
Monthly Cost $5/mo
Google Tag Manager
Tag Manager
Costly
Execution 359ms
Transfer 158 KB
Unused 40%
Monthly Cost $5/mo
Google Tag Manager
Tag Manager
Costly
Execution 278ms
Transfer 128 KB
Unused 47%
Monthly Cost $4/mo
www.youtube.com
Other
Costly
Execution 203ms
Transfer 11 KB
Monthly Cost $3/mo
cdn.parsely.com
Other
Optional
Execution 190ms
Transfer 26 KB
Monthly Cost $3/mo
dap.digitalgov.gov
Other
Optional
Execution 74ms
Transfer 4 KB
Monthly Cost $1/mo

These scripts may cost more than they're worth

  • Unattributable adds 798ms and costs ~$11/month
  • Google Tag Manager adds 392ms and costs ~$5/month
  • Google Tag Manager adds 359ms and costs ~$5/month
  • Google Tag Manager adds 278ms and costs ~$4/month
  • www.youtube.com adds 203ms and costs ~$3/month

Unattributable takes 798ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

Google Tag Manager takes 392ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

Google Tag Manager takes 359ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

Google Tag Manager takes 278ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

www.youtube.com takes 203ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

How third-party costs are calculated

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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