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https://www.rightmove.co.uk

Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
77
GRADE
C
FIX
4
REVIEW
3
PASS
7
INFO
2

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

Mobile Desktop
49
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
99
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.

2.34 s

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

5.07 s

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

3.20 s

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.

2.92 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.

13.40 s

Page Load Progression

375 ms
750 ms
1.1 s
1.5 s
1.9 s
2.2 s
2.6 s
3.0 s
Checks
16
7 PASS 3 REVIEW 4 FIX
D
Third-Party Impact
Action
88% third-party, 0 ms blocking
FIX
88% third-party, 0 ms blocking
Warning::
Third-party code accounts for 88% of page weight (1.7 MiB of 1.9 MiB)
Info::
Third-party blocking time is low (0 ms)
88%
First-party Third-party
F
JS Execution Cost
Action
5243ms total JS execution
FIX
5243ms total JS execution
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-5RS...: 772ms CPU time
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-PCC...: 732ms CPU time
Warning::
https://www.googletagmanager.com/gtag/js?id=G-Z2N6...: 673ms CPU time
Warning::
https://media.rightmove.co.uk/assets/7fb0c8adf9bad...: 574ms CPU time
Warning::
https://media.rightmove.co.uk/assets/7fb0c8adf9bad...: 510ms CPU time
Warning::
Third-party scripts: 4679ms (89% of total)

Main Thread Breakdown

Script Evaluation 64% Script Parsing & Compilation 22% Other 7%
ScriptTotalScriptingParse/CompileParty
https://www.googletagmanager.com/gtm.js?id=GTM-5RSKHCJL&l=rightmoveDataLayer&gtm=4e6460h1772ms684ms52ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-PCCWWRS&l=rightmoveDataLayer&gtm=4e6460h1732ms520ms187ms3rd
https://www.googletagmanager.com/gtag/js?id=G-Z2N66DNEZM&l=rightmoveDataLayer&cx=c&gtm=4e6460h1673ms332ms286ms3rd
https://media.rightmove.co.uk/assets/7fb0c8adf9bad14b85d82c635308c18c/main.bundle.4c0eb3191280858c4d89.js574ms218ms347ms3rd
https://media.rightmove.co.uk/assets/7fb0c8adf9bad14b85d82c635308c18c/shared.bundle.ce72b57457c9cd546ee9.js510ms458ms44ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-MVTJNDT&l=rightmoveDataLayer451ms393ms51ms3rd
https://www.rightmove.co.uk/360ms53ms25ms1st
Unattributable290ms22ms0ms3rd
https://www.rightmove.co.uk/federated/assets/61391f644effa772267c6525fd386cba/client/918-5174d3bb46ddc7cd5d60.js203ms130ms73ms1st
https://www.googletagmanager.com/gtag/js?id=AW-1046760651&l=rightmoveDataLayer&cx=c&gtm=4e6460h1191ms157ms33ms3rd

Showing top 10 of 13 scripts

F
JS Bundles
Action
19 scripts, 705 KB unused
FIX
19 scripts, 705 KB unused
Warning::
https://www.rightmove.co.uk/federated/assets/61391...: 101 KB unused (71%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://media.rightmove.co.uk/assets/7fb0c8adf9bad...: 90 KB unused (69%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-5RS...: 70 KB unused (36%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtag/js?id=G-Z2N6...: 66 KB unused (40%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-MVT...: 64 KB unused (52%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 705 KB
705 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.rightmove.co.uk/federated/assets/61391f644effa772267c6525fd386cba/client/918-5174d3bb46ddc7cd5d60.js143 KB101 KB (71%)✓1st
https://media.rightmove.co.uk/assets/7fb0c8adf9bad14b85d82c635308c18c/main.bundle.4c0eb3191280858c4d89.js251 KB90 KB (69%)✓3rd
https://www.googletagmanager.com/gtm.js?id=GTM-5RSKHCJL&l=rightmoveDataLayer&gtm=4e6460h1197 KB70 KB (36%)✓3rd
https://www.googletagmanager.com/gtag/js?id=G-Z2N66DNEZM&l=rightmoveDataLayer&cx=c&gtm=4e6460h1168 KB66 KB (40%)✓3rd
https://www.googletagmanager.com/gtm.js?id=GTM-MVTJNDT&l=rightmoveDataLayer123 KB64 KB (52%)✓3rd
https://www.googletagmanager.com/gtag/js?id=AW-792861408&l=rightmoveDataLayer&cx=c&gtm=4e6460h1136 KB64 KB (47%)✓3rd
https://www.googletagmanager.com/gtag/js?id=AW-1046760651&l=rightmoveDataLayer&cx=c&gtm=4e6460h1136 KB64 KB (47%)✓3rd
https://www.googletagmanager.com/gtag/js?id=DC-14702053&l=rightmoveDataLayer&cx=c&gtm=4e6460h1129 KB62 KB (48%)✓3rd
https://www.googletagmanager.com/gtag/js?id=DC-9049902&l=rightmoveDataLayer&cx=c&gtm=4e6460h1129 KB59 KB (46%)✓3rd
https://www.googletagmanager.com/gtm.js?id=GTM-PCCWWRS&l=rightmoveDataLayer&gtm=4e6460h1166 KB44 KB (27%)✓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

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
Page Weight Budget
Action
1.9 MB transferred, 41 requests
REVIEW
1.9 MB transferred, 41 requests
Info::
Page weighs 6.5 MB (1.9 MB transferred)
Warning::
JavaScript is 1.6 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.6 MB
Info::
41 HTTP requests
Info::
Estimated 0.40 g CO2 per page load
1.9 MB / 2.4 MB budget
1.9 MB transferred
41 requests
0.40 g CO2 per page load
JavaScript 1.6 MiB 86%
Images 102.2 KiB 5%
HTML 58.1 KiB 3%
Fonts 52.4 KiB 3%
CSS 49.4 KiB 3%
Other 3.9 KiB 0%
Other 2.8 KiB 0%
Other 819 B 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Approaching limit

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

B
Image Optimization
8 images, 0 KB saveable
REVIEW
8 images, 0 KB saveable
Info::
All images are well-optimized
8 images 102 KB
0 oversized -0 KB
5 legacy format
0 missing dimensions CLS risk
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 (52 KB)
PASS
2 fonts (52 KB)
Info::
2 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

2

52 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 5.0 s FCP 2.3 s LCP 5.1 shttps://media.rightmove.co.uk/assets/shared-fonts/effra/Effra_WLatn_Md.woff2Effra_WLatn_Md.woff2 https://media.rightmove.co.uk/assets/shared-fonts/effra/Effra_WLatn_Md.woff2 — 25.7 KiB — 0 ms — font-display: swaphttps://media.rightmove.co.uk/assets/shared-fonts/effra/Effra_WLatn_Rg.woff2Effra_WLatn_Rg.woff2 https://media.rightmove.co.uk/assets/shared-fonts/effra/Effra_WLatn_Rg.woff2 — 26.7 KiB — 0 ms — font-display: swap
Effra_WLatn_Md.woff2 woff2 swap
Size 26 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Effra_WLatn_Rg.woff2 woff2 swap
Size 27 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
1 hints, 0 missing preconnects
PASS
1 hints, 0 missing preconnects
Info::
Page uses 1 resource hint(s)

Current Resource Hints

preconnect
1
preload
—
dns-prefetch
—
prefetch
—

1 resource hints configured

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
41 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
89% of JavaScript execution is third-party
First-party Third-party 4679ms · 1496KB · £48/mo
Google Tag Manager
Tag Manager
Costly
Execution 772ms
Transfer 197 KB
Unused 36%
Monthly Cost £8/mo
Google Tag Manager
Tag Manager
Costly
Execution 732ms
Transfer 166 KB
Unused 27%
Monthly Cost £8/mo
Google Tag Manager
Tag Manager
Costly
Execution 673ms
Transfer 168 KB
Unused 40%
Monthly Cost £7/mo
media.rightmove.co.uk
Other
Costly
Execution 574ms
Transfer 251 KB
Unused 69%
Monthly Cost £6/mo
media.rightmove.co.uk
Other
Costly
Execution 510ms
Transfer 63 KB
Unused 34%
Monthly Cost £5/mo
Google Tag Manager
Tag Manager
Costly
Execution 451ms
Transfer 123 KB
Unused 52%
Monthly Cost £5/mo
Unattributable
Other
Costly
Execution 290ms
Transfer 0 KB
Monthly Cost £3/mo
Google Tag Manager
Tag Manager
Optional
Execution 191ms
Transfer 136 KB
Unused 47%
Monthly Cost £2/mo
Google Tag Manager
Tag Manager
Optional
Execution 169ms
Transfer 129 KB
Unused 46%
Monthly Cost £2/mo
Google Tag Manager
Tag Manager
Optional
Execution 167ms
Transfer 136 KB
Unused 47%
Monthly Cost £2/mo
Google Tag Manager
Tag Manager
Optional
Execution 150ms
Transfer 129 KB
Unused 48%
Monthly Cost £2/mo

These scripts may cost more than they're worth

  • Google Tag Manager adds 772ms and costs ~£8/month
  • Google Tag Manager adds 732ms and costs ~£8/month
  • Google Tag Manager adds 673ms and costs ~£7/month
  • media.rightmove.co.uk adds 574ms and costs ~£6/month
  • media.rightmove.co.uk adds 510ms and costs ~£5/month
  • Google Tag Manager adds 451ms and costs ~£5/month
  • Unattributable adds 290ms and costs ~£3/month

89% 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

Google Tag Manager takes 772ms 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 732ms 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 673ms 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

media.rightmove.co.uk takes 574ms 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

69% of media.rightmove.co.uk'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

media.rightmove.co.uk takes 510ms 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 451ms 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

52% of Google Tag Manager'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

Unattributable takes 290ms 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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