Skip to content
https://craigslist.org

Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
88
GRADE
B
FIX
2
REVIEW
3
PASS
9
INFO
2

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

Mobile Desktop
35
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.
100
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.

3.19 s

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

7.83 s

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

522 ms

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

0.255

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

9.06 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.

7.83 s

Page Load Progression

661 ms
1.3 s
2.0 s
2.6 s
3.3 s
4.0 s
4.6 s
5.3 s
Checks
16
9 PASS 3 REVIEW 2 FIX
D
Third-Party Impact
Action
100% third-party, 0 ms blocking
FIX
100% third-party, 0 ms blocking
Warning::
Third-party code accounts for 100% of page weight (784.6 KiB of 784.8 KiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
F
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

C
JS Execution Cost
Action
1688ms total JS execution
REVIEW
1688ms total JS execution
Warning::
https://www.craigslist.org/static/www/d58afecda526...: 1014ms CPU time
Warning::
https://paris.craigslist.org/: 295ms CPU time
Info::
Unattributable: 198ms CPU time
Info::
https://www.craigslist.org/static/www/browsePostin...: 181ms CPU time
Warning::
Third-party scripts: 1688ms (100% of total)

Main Thread Breakdown

Script Evaluation 53% Style & Layout 16% Other 13% Script Parsing & Compilation 11% Rendering 4%
ScriptTotalScriptingParse/CompileParty
https://www.craigslist.org/static/www/d58afecda5261cb9fcb91b2d144412254d004485.js1014ms883ms2ms3rd
https://paris.craigslist.org/295ms12ms1ms3rd
Unattributable198ms4ms0ms3rd
https://www.craigslist.org/static/www/browsePostings-2026-04-07-10-38-0fd1d88a29dc55c2b86f0359e68457ac878bf0ee.js181ms5ms176ms3rd
C
JS Bundles
Action
4 scripts, 278 KB unused
REVIEW
4 scripts, 278 KB unused
Warning::
https://www.craigslist.org/static/www/browsePostin...: 278 KB unused (46%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 278 KB
278 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.craigslist.org/static/www/browsePostings-2026-04-07-10-38-0fd1d88a29dc55c2b86f0359e68457ac878bf0ee.js605 KB278 KB (46%)✓3rd
https://www.craigslist.org/static/www/d58afecda5261cb9fcb91b2d144412254d004485.js9 KB—✓3rd
https://www.craigslist.org/static/d/5918794/www/manifest.js6 KB—✓3rd
https://www.craigslist.org/static/www/fr-FR-2026-01-05-06-47-945d2cbabdf1092d18bd82e8e92f9cbf2d047785.es5.js26 KB—✓3rd

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
Page Weight Budget
785 KB transferred, 13 requests
PASS
785 KB transferred, 13 requests
Info::
Page weighs 2.5 MB (785 KB transferred)
Warning::
JavaScript is 646 KB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 646 KB
Info::
13 HTTP requests
Info::
Estimated 0.16 g CO2 per page load
785 KB / 2.4 MB budget
785 KB transferred
13 requests
0.16 g CO2 per page load
JavaScript 645.9 KiB 82%
CSS 70.0 KiB 9%
Fonts 31.0 KiB 4%
Images 21.0 KiB 3%
HTML 12.8 KiB 2%
Other 4.2 KiB 1%
0 2.4 MB 4.9 MB
Under budget

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

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+
Image Optimization
1 images, 0 KB saveable
PASS
1 images, 0 KB saveable
Info::
All images are well-optimized
1 images 21 KB
0 oversized -0 KB
1 legacy format
0 missing dimensions CLS risk
A+
Font Loading
1 fonts (31 KB)
PASS
1 fonts (31 KB)
Info::
1 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

1

31 KB total

Render-blocking

0

of 1

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 5.0 s 6.0 s 7.0 s 8.0 s FCP 3.2 s LCP 7.8 sdata:application/x-font-ttf;charset=utf-8;base64,AAEAAAALAIAAAwAwT1MvMg8SDlMAAAC8AAAAYGNtYXAC2AENAA…x-font-ttf;charset=utf-... data:application/x-font-ttf;charset=utf-8;base64,AAEAAAALAIAAAwAwT1MvMg8SDlMAAAC8AAAAYGNtYXAC2AENAA… — 31.0 KiB — 0 ms — font-display: swap
x-font-ttf;charset=utf-... unknown swap
Size 31 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)

Fixing the unchecked items could save ~9 KB and ~18 ms

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
Network Waterfall
13 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
100% of JavaScript execution is third-party
First-party Third-party 1688ms · 625KB · $22/mo
www.craigslist.org
Other
Costly
Execution 1014ms
Transfer 9 KB
Monthly Cost $13/mo
paris.craigslist.org
Other
Costly
Execution 295ms
Transfer 11 KB
Monthly Cost $4/mo
Unattributable
Other
Optional
Execution 198ms
Transfer 0 KB
Monthly Cost $3/mo
www.craigslist.org
Other
Optional
Execution 181ms
Transfer 605 KB
Unused 46%
Monthly Cost $2/mo

These scripts may cost more than they're worth

  • www.craigslist.org adds 1014ms and costs ~$13/month
  • paris.craigslist.org adds 295ms and costs ~$4/month

100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.

Why this matters

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.craigslist.org takes 1014ms 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

paris.craigslist.org takes 295ms 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.

Send Feedback