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https://www.spacex.com

Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
80
GRADE
B
FIX
2
REVIEW
3
PASS
7
INFO
2

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

Mobile Desktop
73
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
85
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.
82
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.

487 ms

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

1.36 s

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

594 ms

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

0.001

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

672 ms

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

1.36 s

Page Load Progression

881 ms
1.8 s
2.6 s
3.5 s
4.4 s
5.3 s
6.2 s
7.0 s
Checks
14
7 PASS 3 REVIEW 2 FIX
F
Page Weight Budget
Action
15.2 MB transferred, 35 requests
FIX
15.2 MB transferred, 35 requests
Critical::
Page weighs 14.8 MB (15.2 MB transferred)
Warning::
Images are 1.4 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 1.4 MB
Info::
35 HTTP requests
Info::
Estimated 3.2 g CO2 per page load
15.2 MB / 2.4 MB budget
15.2 MB transferred
35 requests
3.2 g CO2 per page load
Other 13.4 MiB 89%
Images 1.4 MiB 9%
JavaScript 237.4 KiB 2%
Fonts 43.7 KiB 0%
Other 11.9 KiB 0%
HTML 2.6 KiB 0%
CSS 2.3 KiB 0%
Other 2.0 KiB 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

D
Third-Party Impact
Action
98% third-party, 0 ms blocking
FIX
98% third-party, 0 ms blocking
Warning::
Third-party code accounts for 98% of page weight (14.9 MiB of 15.2 MiB)
Info::
Third-party blocking time is low (0 ms)
98%
First-party Third-party
B
Image Optimization
7 images, 0 KB saveable
REVIEW
7 images, 0 KB saveable
Info::
All images are well-optimized
7 images 1.4 MB
0 oversized -0 KB
7 legacy format
0 missing dimensions CLS risk
C
JS Execution Cost
Action
1267ms total JS execution
REVIEW
1267ms total JS execution
Warning::
https://www.spacex.com/: 903ms CPU time
Info::
Unattributable: 222ms CPU time
Info::
https://www.spacex.com/vendor.ca6bf32c26e75d4a.js: 81ms CPU time
Info::
https://www.spacex.com/polyfills.08b6611321d68f0c....: 61ms CPU time
Info::
Third-party scripts: 222ms (18% of total)

Main Thread Breakdown

Other 83% Script Evaluation 13%
ScriptTotalScriptingParse/CompileParty
https://www.spacex.com/903ms2ms0ms1st
Unattributable222ms29ms0ms3rd
https://www.spacex.com/vendor.ca6bf32c26e75d4a.js81ms78ms1ms1st
https://www.spacex.com/polyfills.08b6611321d68f0c.js61ms52ms0ms1st
B
JS Bundles
10 scripts, 94 KB unused
REVIEW
10 scripts, 94 KB unused
Warning::
https://www.spacex.com/vendor.ca6bf32c26e75d4a.js: 94 KB unused (56%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 94 KB
94 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.spacex.com/vendor.ca6bf32c26e75d4a.js167 KB94 KB (56%)✓1st
https://www.spacex.com/environment.js0 KB—✓1st
https://www.spacex.com/runtime.2c0f56a135f2b763.js3 KB—✓1st
https://www.spacex.com/polyfills.08b6611321d68f0c.js23 KB—✓1st
https://www.spacex.com/main.f5e02a8ad9f09a96.js18 KB—✓1st
https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da177152312451611 KB—✓3rd
https://www.spacex.com/7753.5efeb53f2f091644.js1 KB—✓1st
https://www.spacex.com/2248.1c995e45edcf7105.js4 KB—✓1st
https://www.spacex.com/common.9dc1d69e3201c9a1.js8 KB—✓1st
https://www.spacex.com/8119.f4e5c33ecc356475.js3 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

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
2 fonts (44 KB)
PASS
2 fonts (44 KB)
Info::
2 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

2

44 KB total

Render-blocking

0

of 2

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s FCP 487 ms LCP 1.4 shttps://www.spacex.com/D-DIN.e58c68e58b09fc0e.woff2D-DIN.e58c68e58b09fc0e.... https://www.spacex.com/D-DIN.e58c68e58b09fc0e.woff2 — 21.2 KiB — 0 ms — font-display: swaphttps://www.spacex.com/D-DIN-Bold.9a5ce67e997fd030.woff2D-DIN-Bold.9a5ce67e997f... https://www.spacex.com/D-DIN-Bold.9a5ce67e997fd030.woff2 — 22.5 KiB — 0 ms — font-display: swap
D-DIN.e58c68e58b09fc0e.... woff2 swap
Size 21 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
D-DIN-Bold.9a5ce67e997f... woff2 swap
Size 22 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+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Cloudflare

A+
HTTP Caching
max-age=600 (10 minutes)
PASS
max-age=600 (10 minutes)
Info::
Cache-Control header is set
Got: public, max-age=600
Info::
Effective TTL: 10 minutes (max-age=600)
Info::
Last-Modified header present
Cache-Control

public, max-age=600

DirectiveValueMeaning
public—Any cache may store this response
max-age600Cache for 10 minutes
Effective TTL: 600 seconds
Network Waterfall
35 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
18% of JavaScript execution is third-party
First-party Third-party 222ms · 0KB · €2/mo
Unattributable
Other
Costly
Execution 222ms
Transfer 0 KB
Monthly Cost €2/mo

These scripts may cost more than they're worth

  • Unattributable adds 222ms and costs ~€2/month

Unattributable takes 222ms 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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