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https://www.spacex.com

Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
80
GRADE
B
FIX
2
REVIEW
3
PASS
9
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.
83
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.

2.11 s

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

4.61 s

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

279 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.

2.27 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.

5.21 s

Page Load Progression

885 ms
1.8 s
2.7 s
3.5 s
4.4 s
5.3 s
6.2 s
7.1 s
Checks
16
9 PASS 3 REVIEW 2 FIX
F
Page Weight Budget
Action
10.7 MB transferred, 37 requests
FIX
10.7 MB transferred, 37 requests
Critical::
Page weighs 11.6 MB (10.7 MB transferred)
Info::
37 HTTP requests
Info::
Estimated 2.2 g CO2 per page load
10.7 MB / 2.4 MB budget
10.7 MB transferred
37 requests
2.2 g CO2 per page load
Other 9.8 MiB 92%
Images 595.5 KiB 5%
JavaScript 237.4 KiB 2%
Fonts 42.9 KiB 0%
Other 11.9 KiB 0%
CSS 3.0 KiB 0%
HTML 2.6 KiB 0%
Other 2.0 KiB 0%
0 2.4 MB 4.9 MB
Over budget
D
Third-Party Impact
Action
97% third-party, 0 ms blocking
FIX
97% third-party, 0 ms blocking
Warning::
Third-party code accounts for 97% of page weight (10.4 MiB of 10.7 MiB)
Info::
Third-party blocking time is low (0 ms)
97%
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 595 KB
0 oversized -0 KB
7 legacy format
0 missing dimensions CLS risk
C
JS Execution Cost
Action
1385ms total JS execution
REVIEW
1385ms total JS execution
Warning::
Unattributable: 584ms CPU time
Warning::
https://www.spacex.com/polyfills.08b6611321d68f0c....: 304ms CPU time
Warning::
https://www.spacex.com/vendor.ca6bf32c26e75d4a.js: 275ms CPU time
Info::
https://www.spacex.com/: 222ms CPU time
Info::
Third-party scripts: 584ms (42% of total)

Main Thread Breakdown

Script Evaluation 48% Other 41% Style & Layout 6% Rendering 3%
ScriptTotalScriptingParse/CompileParty
Unattributable584ms122ms0ms3rd
https://www.spacex.com/polyfills.08b6611321d68f0c.js304ms255ms0ms1st
https://www.spacex.com/vendor.ca6bf32c26e75d4a.js275ms267ms2ms1st
https://www.spacex.com/222ms7ms1ms1st
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 (43 KB)
PASS
2 fonts (43 KB)
Info::
2 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

2

43 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 1.0 s 2.0 s 3.0 s 4.0 s FCP 2.1 s LCP 4.6 shttps://www.spacex.com/D-DIN.e58c68e58b09fc0e.woff2D-DIN.e58c68e58b09fc0e.... https://www.spacex.com/D-DIN.e58c68e58b09fc0e.woff2 — 20.4 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 20 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+
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+
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
37 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 584ms · 0KB · €6/mo
Unattributable
Other
Costly
Execution 584ms
Transfer 0 KB
Monthly Cost €6/mo

These scripts may cost more than they're worth

  • Unattributable adds 584ms and costs ~€6/month

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

Unattributable takes 584ms 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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