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Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
71
GRADE
C
FIX
5
REVIEW
2
PASS
7
INFO
2

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

Mobile Desktop
26
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
81
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
77
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
92
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.

4.80 s

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

24.54 s

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

5.74 s

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

0.051

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

13.90 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.

36.24 s

Page Load Progression

623 ms
1.2 s
1.9 s
2.5 s
3.1 s
3.7 s
4.4 s
5.0 s
Checks
16
7 PASS 2 REVIEW 5 FIX
F
Page Weight Budget
Action
6.6 MB transferred, 232 requests
FIX
6.6 MB transferred, 232 requests
Critical::
Page weighs 22.1 MB (6.6 MB transferred)
Warning::
JavaScript is 4.9 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 4.9 MB
Warning::
Images are 1.3 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 1.3 MB
Warning::
232 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 1.4 g CO2 per page load
6.6 MB / 2.4 MB budget
6.6 MB transferred
232 requests
1.4 g CO2 per page load
JavaScript 4.9 MiB 74%
Images 1.3 MiB 20%
CSS 171.3 KiB 3%
Other 71.0 KiB 1%
HTML 70.7 KiB 1%
Fonts 28.8 KiB 0%
Other 21.8 KiB 0%
Other 14.9 KiB 0%
Other 7.1 KiB 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Over 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

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

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
93% third-party, 0 ms blocking
FIX
93% third-party, 0 ms blocking
Warning::
Third-party code accounts for 93% of page weight (6.1 MiB of 6.6 MiB)
Info::
Third-party blocking time is low (0 ms)
93%
First-party Third-party
F
JS Execution Cost
Action
22715ms total JS execution
FIX
22715ms total JS execution
Warning::
https://22af5ed32a4a.edge.sdk.awswaf.com/22af5ed32...: 5899ms CPU time
Warning::
https://prod.cdn-redfin.com/bundles/customer-pages...: 3585ms CPU time
Warning::
Unattributable: 2593ms CPU time
Warning::
https://www.redfin.com/: 1869ms CPU time
Warning::
https://www.googletagmanager.com/gtag/js?id=G-928P...: 1457ms CPU time
Warning::
Third-party scripts: 20571ms (91% of total)

Main Thread Breakdown

Script Evaluation 69% Other 16% Script Parsing & Compilation 8%
ScriptTotalScriptingParse/CompileParty
https://22af5ed32a4a.edge.sdk.awswaf.com/22af5ed32a4a/939b6cb0e48b/challenge.js5899ms5231ms184ms3rd
https://prod.cdn-redfin.com/bundles/customer-pages-personalization/4f01b5f3087c9b5d3770.js3585ms2985ms106ms3rd
Unattributable2593ms371ms0ms3rd
https://www.redfin.com/1869ms178ms52ms1st
https://www.googletagmanager.com/gtag/js?id=G-928P0PZ00X&cx=c&gtm=4e64601457ms1295ms57ms3rd
https://prod.cdn-redfin.com/bundles/customer-pages-personalization/c1bae9b3c77451aaa3bf.js1408ms1338ms35ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-TZTT5H1100ms914ms123ms3rd
https://cdn.cookielaw.org/scripttemplates/202512.1.0/otBannerSdk.js752ms520ms108ms3rd
https://cdn.cookielaw.org/scripttemplates/202512.1.0/otGPP.js646ms565ms46ms3rd
https://cdn.cookielaw.org/scripttemplates/otSDKStub.js369ms298ms10ms3rd

Showing top 10 of 31 scripts

F
JS Bundles
Action
59 scripts, 1.4 MB unused
FIX
59 scripts, 1.4 MB unused
Warning::
https://22af5ed32a4a.edge.sdk.awswaf.com/22af5ed32...: 256 KB unused (51%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://prod.cdn-redfin.com/bundles/customer-pages...: 199 KB unused (63%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://prod.cdn-redfin.com/bundles/customer-pages...: 160 KB unused (45%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://prod.cdn-redfin.com/bundles/customer-pages...: 96 KB unused (39%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://prod.cdn-redfin.com/bundles/customer-pages...: 87 KB unused (54%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 1.4 MB
1441 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://22af5ed32a4a.edge.sdk.awswaf.com/22af5ed32a4a/939b6cb0e48b/challenge.js501 KB256 KB (51%)✓3rd
https://prod.cdn-redfin.com/bundles/customer-pages-personalization/22651796b6dce9a62e9b.js314 KB199 KB (63%)✓3rd
https://prod.cdn-redfin.com/bundles/customer-pages-personalization/18b8f4f0f807e50242cd.js357 KB160 KB (45%)✓3rd
https://prod.cdn-redfin.com/bundles/customer-pages-personalization/4f01b5f3087c9b5d3770.js244 KB96 KB (39%)✓3rd
https://prod.cdn-redfin.com/bundles/customer-pages-personalization/50191368361583f43278.js162 KB87 KB (54%)✓3rd
https://accounts.google.com/gsi/client93 KB69 KB (75%)✓3rd
https://www.googletagmanager.com/gtag/js?id=G-928P0PZ00X&cx=c&gtm=4e6460160 KB65 KB (41%)✓3rd
https://cdn.cookielaw.org/scripttemplates/202512.1.0/otBannerSdk.js126 KB63 KB (50%)✓3rd
https://cdn.cookielaw.org/scripttemplates/202512.1.0/otBannerSdk.js0 KB63 KB (50%)✓3rd
https://www.googletagmanager.com/gtag/js?id=DC-16107967&cx=c&gtm=4e6460129 KB56 KB (43%)✓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

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

D
HTTP Caching
Action
no-store (uncacheable)
FIX
no-store (uncacheable)
Info::
Cache-Control: no-store prevents all caching
Intentional for dynamic content, but increases server load for every page view.
Got: max-age=0, no-cache, no-store, private
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

max-age=0, no-cache, no-store, private

DirectiveValueMeaning
max-age0Cache for 0 seconds
no-cache—Cache but always revalidate first
no-store—Never cache this response
private—Only browser cache, not CDN/proxy
B
Image Optimization
37 images, 0 KB saveable
REVIEW
37 images, 0 KB saveable
Warning::
https://ssl.cdn-redfin.com/cop-assets/prod/hpwidge... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
37 images 1.3 MB
0 oversized -0 KB
36 legacy format
1 missing dimensions CLS risk

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

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
2 fonts (29 KB)
PASS
2 fonts (29 KB)
Info::
2 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

2

29 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 2.0 s 4.0 s 6.0 s 8.0 s 10.0 s 12.0 s 14.0 s 16.0 s 18.0 s 20.0 s 22.0 s 24.0 s FCP 4.8 s LCP 24.5 sdata:font/woff2;base64,d09GMgABAAAAADiwABAAAAAA2rQAADhMAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAP0ZGVE0cGh4b…woff2;base64,d09GMgABAA... data:font/woff2;base64,d09GMgABAAAAADiwABAAAAAA2rQAADhMAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAP0ZGVE0cGh4b… — 14.2 KiB — 0 ms — font-display: swapdata:font/woff2;base64,d09GMgABAAAAADqUABAAAAAA3LAAADoyAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAP0ZGVE0cGh4b…woff2;base64,d09GMgABAA... data:font/woff2;base64,d09GMgABAAAAADqUABAAAAAA3LAAADoyAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAP0ZGVE0cGh4b… — 14.6 KiB — 0 ms — font-display: swap
woff2;base64,d09GMgABAA... woff2 swap
Size 14 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
woff2;base64,d09GMgABAA... woff2 swap
Size 15 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
Network Waterfall
232 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
91% of JavaScript execution is third-party
First-party Third-party 20571ms · 3068KB · $273/mo
22af5ed32a4a.edge.sdk.awswaf.com
Other
Costly
Execution 5899ms
Transfer 501 KB
Unused 51%
Monthly Cost $78/mo
prod.cdn-redfin.com
Other
Costly
Execution 3585ms
Transfer 244 KB
Unused 39%
Monthly Cost $48/mo
Unattributable
Other
Costly
Execution 2593ms
Transfer 0 KB
Monthly Cost $34/mo
Google Tag Manager
Tag Manager
Costly
Execution 1457ms
Transfer 160 KB
Unused 41%
Monthly Cost $19/mo
prod.cdn-redfin.com
Other
Costly
Execution 1408ms
Transfer 70 KB
Unused 46%
Monthly Cost $19/mo
Google Tag Manager
Tag Manager
Costly
Execution 1100ms
Transfer 199 KB
Unused 24%
Monthly Cost $15/mo
OneTrust
Consent
Essential
Execution 752ms
Transfer 0 KB
Unused 50%
Monthly Cost $10/mo
OneTrust
Consent
Essential
Execution 646ms
Transfer 22 KB
Monthly Cost $9/mo
OneTrust
Consent
Essential
Execution 369ms
Transfer 9 KB
Monthly Cost $5/mo
analytics.tiktok.com
Other
Costly
Execution 293ms
Transfer 110 KB
Unused 51%
Monthly Cost $4/mo
Google Tag Manager
Tag Manager
Costly
Execution 226ms
Transfer 144 KB
Unused 36%
Monthly Cost $3/mo
Facebook Pixel
Advertising
Optional
Execution 198ms
Transfer 95 KB
Unused 31%
Monthly Cost $3/mo
Google Tag Manager
Tag Manager
Optional
Execution 198ms
Transfer 129 KB
Unused 43%
Monthly Cost $3/mo
c.hrzn-nxt.com
Other
Optional
Execution 189ms
Transfer 30 KB
Monthly Cost $3/mo
Google Tag Manager
Tag Manager
Optional
Execution 187ms
Transfer 129 KB
Unused 43%
Monthly Cost $2/mo
Google Tag Manager
Tag Manager
Optional
Execution 183ms
Transfer 129 KB
Unused 43%
Monthly Cost $2/mo
prod.cdn-redfin.com
Other
Optional
Execution 166ms
Transfer 357 KB
Unused 45%
Monthly Cost $2/mo
prod.cdn-redfin.com
Other
Optional
Execution 163ms
Transfer 314 KB
Unused 63%
Monthly Cost $2/mo
Facebook Pixel
Advertising
Optional
Execution 154ms
Transfer 39 KB
Monthly Cost $2/mo
Facebook Pixel
Advertising
Optional
Execution 119ms
Transfer 15 KB
Monthly Cost $2/mo
sb.scorecardresearch.com
Other
Optional
Execution 115ms
Transfer 0 KB
Monthly Cost $2/mo
Google Analytics
Analytics
Optional
Execution 97ms
Transfer 21 KB
Monthly Cost $1/mo
Bing UET
Advertising
Optional
Execution 91ms
Transfer 16 KB
Monthly Cost $1/mo
prod.cdn-redfin.com
Other
Optional
Execution 75ms
Transfer 162 KB
Unused 54%
Monthly Cost $1/mo
analytics.tiktok.com
Other
Optional
Execution 70ms
Transfer 40 KB
Monthly Cost $1/mo
accounts.google.com
Other
Optional
Execution 67ms
Transfer 93 KB
Unused 75%
Monthly Cost $1/mo
cdn.pdst.fm
Other
Optional
Execution 59ms
Transfer 10 KB
Monthly Cost $1/mo
d2hrivdxn8ekm8.cloudfront.net
Other
Optional
Execution 57ms
Transfer 15 KB
Monthly Cost $1/mo
Bing UET
Advertising
Optional
Execution 54ms
Transfer 15 KB
Monthly Cost $1/mo

These scripts may cost more than they're worth

  • 22af5ed32a4a.edge.sdk.awswaf.com adds 5899ms and costs ~$78/month
  • prod.cdn-redfin.com adds 3585ms and costs ~$48/month
  • Unattributable adds 2593ms and costs ~$34/month
  • Google Tag Manager adds 1457ms and costs ~$19/month
  • prod.cdn-redfin.com adds 1408ms and costs ~$19/month
  • Google Tag Manager adds 1100ms and costs ~$15/month
  • analytics.tiktok.com adds 293ms and costs ~$4/month
  • Google Tag Manager adds 226ms and costs ~$3/month

91% 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

22af5ed32a4a.edge.sdk.awswaf.com takes 5899ms 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

51% of 22af5ed32a4a.edge.sdk.awswaf.com's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

Source: web.dev

prod.cdn-redfin.com takes 3585ms 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

Unattributable takes 2593ms 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 1457ms 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

prod.cdn-redfin.com takes 1408ms 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 1100ms 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

50% of OneTrust's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

Source: web.dev

analytics.tiktok.com takes 293ms 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

51% of analytics.tiktok.com's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

Source: web.dev

Google Tag Manager takes 226ms 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

63% of prod.cdn-redfin.com's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

Source: web.dev

54% of prod.cdn-redfin.com's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

Source: web.dev

75% of accounts.google.com's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

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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