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Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
70
GRADE
C
FIX
2
REVIEW
4
PASS
6
INFO
2

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

Mobile Desktop
76
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
93
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.

552 ms

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

1.67 s

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

26 ms

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

0.326

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

1.25 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.

5.73 s

Page Load Progression

598 ms
1.2 s
1.8 s
2.4 s
3.0 s
3.6 s
4.2 s
4.8 s
Checks
14
6 PASS 4 REVIEW 2 FIX
F
Page Weight Budget
Action
9.8 MB transferred, 135 requests
FIX
9.8 MB transferred, 135 requests
Critical::
Page weighs 17.1 MB (9.8 MB transferred)
Warning::
Images are 6.8 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 6.8 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::
135 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 2.1 g CO2 per page load
9.8 MB / 2.4 MB budget
9.8 MB transferred
135 requests
2.1 g CO2 per page load
Images 6.8 MiB 69%
JavaScript 2.2 MiB 22%
Other 364.1 KiB 4%
Fonts 205.6 KiB 2%
CSS 140.0 KiB 1%
HTML 139.3 KiB 1%
Other 24.2 KiB 0%
Other 2.4 KiB 0%
Other 685 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
69% third-party, 0 ms blocking
FIX
69% third-party, 0 ms blocking
Warning::
Third-party code accounts for 69% of page weight (6.8 MiB of 9.8 MiB)
Info::
Third-party blocking time is low (0 ms)
31%
69%
First-party Third-party
B
Image Optimization
54 images, 0 KB saveable
REVIEW
54 images, 0 KB saveable
Info::
All images are well-optimized
54 images 6.8 MB
0 oversized -0 KB
24 legacy format
0 missing dimensions CLS risk
C
JS Execution Cost
Action
1314ms total JS execution
REVIEW
1314ms total JS execution
Warning::
https://www.nasa.gov/: 634ms CPU time
Info::
Unattributable: 170ms CPU time
Info::
https://www.nasa.gov/_static/??-eJyNzk0OAiEMBeALyR...: 132ms CPU time
Info::
https://www.googletagmanager.com/gtag/js?id=G-CSLL...: 101ms CPU time
Info::
https://www.googletagmanager.com/gtag/js?id=G-82GW...: 88ms CPU time
Info::
Third-party scripts: 548ms (42% of total)

Main Thread Breakdown

Script Evaluation 33% Other 29% Style & Layout 16% Rendering 14% Script Parsing & Compilation 5% Parse HTML & CSS 3%
ScriptTotalScriptingParse/CompileParty
https://www.nasa.gov/634ms15ms1ms1st
Unattributable170ms2ms0ms3rd
https://www.nasa.gov/_static/??-eJyNzk0OAiEMBeALyRCNGXRhPEsdGwbSFoXi3+nF6MKVmDSvm+81tdeTCTJRPWKxsc25Yr5/1sBBhlgW9hcyHHwGxW88JVEUtTojt4pAgVfPUzoAGYFLBzJKNZq8J+xIqrck7/zjAQ2MjyS9o2WGjKakKQA1uufd0rn1uBo3bhuftz5wvg==132ms89ms10ms1st
https://www.googletagmanager.com/gtag/js?id=G-CSLL4ZEK4L101ms87ms13ms3rd
https://www.googletagmanager.com/gtag/js?id=G-82GWVTTXCZ&cx=c&gtm=4e641188ms73ms15ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-NLJ258M77ms56ms19ms3rd
https://cdn.parsely.com/keys/nasa.gov/p.js?ver=3.22.063ms54ms7ms3rd
https://www.youtube.com/s/player/f4c47414/www-widgetapi.vflset/www-widgetapi.js51ms45ms2ms3rd
C
JS Bundles
Action
28 scripts, 217 KB unused
REVIEW
28 scripts, 217 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...: 58 KB unused (40%)
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: 217 KB
217 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 KB58 KB (40%)✓3rd
https://www.nasa.gov/_static/??-eJyNzk0OAiEMBeALyRCNGXRhPEsdGwbSFoXi3+nF6MKVmDSvm+81tdeTCTJRPWKxsc25Yr5/1sBBhlgW9hcyHHwGxW88JVEUtTojt4pAgVfPUzoAGYFLBzJKNZq8J+xIqrck7/zjAQ2MjyS9o2WGjKakKQA1uufd0rn1uBo3bhuftz5wvg==63 KB36 KB (57%)✓1st
https://www.youtube.com/s/_/ytembeds/_/js/k=ytembeds.base.en_US.EkHW-yt-vuI.2021.O/am=AAAABQ/d=1/exm=base,root/ed=1/br=1/rs=AGKMywHBjli5eOPfTkoQm_Ycsv7nAWPvPQ/m=r78Drb130 KB—✓3rd
https://dap.digitalgov.gov/Universal-Federated-Analytics-Min.js?agency=NASA&pga4=G-82GWVTTXCZ9 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.js5 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 500 ms 1.0 s 1.5 s FCP 552 ms LCP 1.7 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
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
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
135 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
42% of JavaScript execution is third-party
First-party Third-party 548ms · 469KB · $7/mo
Unattributable
Other
Optional
Execution 170ms
Transfer 0 KB
Monthly Cost $2/mo
Google Tag Manager
Tag Manager
Optional
Execution 101ms
Transfer 146 KB
Unused 40%
Monthly Cost $1/mo
Google Tag Manager
Tag Manager
Optional
Execution 88ms
Transfer 158 KB
Unused 40%
Monthly Cost $1/mo
Google Tag Manager
Tag Manager
Optional
Execution 77ms
Transfer 128 KB
Unused 47%
Monthly Cost $1/mo
cdn.parsely.com
Other
Optional
Execution 63ms
Transfer 26 KB
Monthly Cost $1/mo
www.youtube.com
Other
Optional
Execution 51ms
Transfer 11 KB
Monthly Cost $1/mo

42% of JavaScript execution time comes from third-party scripts.

Why this matters

Third-party scripts (analytics, ads, social, A/B testing) often dominate execution time — every one is a perf-and-privacy tax.

Learn more ▾

Each third-party script is a black box: you don't control when it loads, what it executes, or how much it grows. They often account for a major share of total blocking time on average sites (HTTP Archive's Web Almanac documents the trend). Audit which ones you actually need, defer the rest, and use facade patterns (lite-youtube, lite-vimeo) for embedded media.

Source: web.dev / HTTP Archive Web Almanac

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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