Performance
· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
745 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.09 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
931 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.003
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
3.17 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.
10.27 s
Page Load Progression
1.5 s 3.0 s
4.5 s
6.0 s
7.4 s
8.9 s
10.4 s
11.9 sFPage Weight BudgetAction14.1 MB transferred, 358 requestsFIX
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.
Source: web.dev
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.
Source: web.dev
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.
Source: web.dev
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
FJS Execution CostAction5517ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.sonos.com/_next/static/chunks/3528-22399f527ed2dbbd.js?dpl=dpl_HR77npGmmWfDQznR71rQzE97oiSB | 1220ms | 1079ms | 7ms | 3rd |
| Unattributable | 602ms | 81ms | 0ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-WRJKFWM | 470ms | 331ms | 41ms | 3rd |
| https://www.sonos.com/en/home | 351ms | 22ms | 21ms | 3rd |
| https://forms.sonos.com/w37htfhcq2/vendor/b438b2ba-e8de-42c1-938e-5fc1ebffe53b/main.js?cb=8DCB3ECB413095BC01D1B29BF4757228 | 311ms | 213ms | 15ms | 3rd |
| https://www.sonos.com/s3t4F/Mql/2NIV/Ba/uiwMzO/DOL3tmf6kGNhkzE1/QEQ-AQ/RlQ4d/xxzSxQB | 293ms | 269ms | 18ms | 3rd |
| https://t.contentsquare.net/uxa/0ad82fc9-ef51-4833-83db-2e9207f7b731.js | 286ms | 192ms | 88ms | 3rd |
| https://www.sonos.com/_next/static/chunks/61b5e853-8430af891c2cc329.js?dpl=dpl_HR77npGmmWfDQznR71rQzE97oiSB | 238ms | 163ms | 7ms | 3rd |
| https://www.googletagmanager.com/gtag/destination?id=DC-13670001&cx=c>m=4e64k1 | 205ms | 187ms | 15ms | 3rd |
| https://forms.sonos.com/w37htfhcq2/vendor/b438b2ba-e8de-42c1-938e-5fc1ebffe53b/custom_box.js?cb=8CB4E6AB033008129410B9D3E1038ADA | 192ms | 158ms | 12ms | 3rd |
Showing top 10 of 24 scripts
FJS BundlesAction115 scripts, 1.0 MB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://analytics.sonos.com/p.js | 120 KB | 83 KB (69%) | ✗ | 3rd |
| https://t.contentsquare.net/uxa/0ad82fc9-ef51-4833-83db-2e9207f7b731.js | 141 KB | 76 KB (54%) | ✓ | 3rd |
| https://t.contentsquare.net/uxa/0ad82fc9-ef51-4833-83db-2e9207f7b731.js | 0 KB | 76 KB (54%) | ✓ | 3rd |
| https://t.contentsquare.net/uxa/0ad82fc9-ef51-4833-83db-2e9207f7b731.js | 0 KB | 76 KB (54%) | ✓ | 3rd |
| https://cdn.cookielaw.org/scripttemplates/202505.2.0/otBannerSdk.js | 119 KB | 67 KB (56%) | ✓ | 3rd |
| https://analytics.tiktok.com/i18n/pixel/static/main.MWE0ZWQ3ZWQwOQ.js | 121 KB | 63 KB (52%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/destination?id=DC-13670001&cx=c>m=4e64k1 | 131 KB | 60 KB (46%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-DFV9V8HH8T&cx=c>m=4e64k1 | 176 KB | 58 KB (33%) | ✓ | 3rd |
| https://forms.sonos.com/w37htfhcq2/vendor/b438b2ba-e8de-42c1-938e-5fc1ebffe53b/main.js?cb=8DCB3ECB413095BC01D1B29BF4757228 | 116 KB | 57 KB (49%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=DC-4273294&cx=c>m=4e64k1 | 129 KB | 56 KB (43%) | ✓ | 3rd |
Consider code splitting or tree shaking to reduce unused code.
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.
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.
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.
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.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
FPage Weight InventoryAction358 resources · 14.1 MB · 1.0 MB savings availableFIX
~1.0 MiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 358 resources | 14.1 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
BImage Optimization119 images, 0 KB saveableREVIEW
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
A+Text CompressionAll text resources are compressedPASS
A+Font Loading1 fonts (37 KB)PASS
Web fonts
1
37 KB total
Render-blocking
0
of 1
Dominant font-display
swap
Most common across fonts
Font loading timeline
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 CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
Network Waterfall358 requests over 9609msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.sonos.com www.sonos.com | Other | 1220ms | 51 KB | 46% | $23/mo | Costly |
Unattributable Unattributable | Other | 602ms | 0 KB | — | $11/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 470ms | 201 KB | 26% | $9/mo | Costly |
www.sonos.com www.sonos.com | Other | 351ms | 118 KB | — | $7/mo | Costly |
forms.sonos.com forms.sonos.com | Other | 311ms | 116 KB | 49% | $6/mo | Costly |
www.sonos.com www.sonos.com | Other | 293ms | 1 KB | 21% | $5/mo | Costly |
t.contentsquare.net t.contentsquare.net | Other | 286ms | 0 KB | 54% | $5/mo | Costly |
www.sonos.com www.sonos.com | Other | 238ms | 62 KB | 33% | $4/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 205ms | 131 KB | 46% | $4/mo | Costly |
forms.sonos.com forms.sonos.com | Other | 192ms | 0 KB | 43% | $4/mo | Optional |
analytics.tiktok.com analytics.tiktok.com | Other | 176ms | 121 KB | 52% | $3/mo | Optional |
assets.sonos.com assets.sonos.com | Other | 160ms | 110 KB | 31% | $3/mo | Optional |
Facebook Pixel connect.facebook.net | Advertising | 128ms | 127 KB | 28% | $2/mo | Optional |
www.sonos.com www.sonos.com | Other | 123ms | 33 KB | — | $2/mo | Optional |
OneTrust cdn.cookielaw.org | Consent | 109ms | 119 KB | 56% | $2/mo | Essential |
Google Tag Manager www.googletagmanager.com | Tag Manager | 91ms | 176 KB | 33% | $2/mo | Optional |
www.sonos.com www.sonos.com | Other | 84ms | 6 KB | — | $2/mo | Optional |
www.sonos.com www.sonos.com | Other | 80ms | 9 KB | — | $2/mo | Optional |
sc-static.net sc-static.net | Other | 77ms | 25 KB | — | $1/mo | Optional |
www.sonos.com www.sonos.com | Other | 73ms | 49 KB | — | $1/mo | Optional |
www.sonos.com www.sonos.com | Other | 67ms | 29 KB | — | $1/mo | Optional |
Facebook Pixel connect.facebook.net | Advertising | 66ms | 97 KB | 34% | $1/mo | Optional |
js.appboycdn.com js.appboycdn.com | Other | 62ms | 63 KB | — | $1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 52ms | 129 KB | 43% | $1/mo | Optional |
These scripts may cost more than they're worth
- www.sonos.com adds 1220ms and costs ~$23/month
- Unattributable adds 602ms and costs ~$11/month
- Google Tag Manager adds 470ms and costs ~$9/month
- www.sonos.com adds 351ms and costs ~$7/month
- forms.sonos.com adds 311ms and costs ~$6/month
- www.sonos.com adds 293ms and costs ~$5/month
- t.contentsquare.net adds 286ms and costs ~$5/month
- www.sonos.com adds 238ms and costs ~$4/month
- Google Tag Manager adds 205ms and costs ~$4/month
100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
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.sonos.com takes 1220ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Unattributable takes 602ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Google Tag Manager takes 470ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
www.sonos.com takes 351ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
forms.sonos.com takes 311ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
www.sonos.com takes 293ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
t.contentsquare.net takes 286ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
54% of t.contentsquare.net's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
www.sonos.com takes 238ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Google Tag Manager takes 205ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
52% of analytics.tiktok.com's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
56% of OneTrust's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev