Performance
· 22 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.
509 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.12 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
11 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.000
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
837 ms
Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.
1.86 s
Page Load Progression
DPage Weight BudgetAction2.2 MB transferred, 343 requestsFIX
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
DPage Weight InventoryAction343 resources · 2.2 MB · 203 KB savings availableFIX
~202.6 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 343 resources | 2.2 MiB | ||||||
CImage OptimizationAction24 images, 0 KB saveableREVIEW
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
CJS Execution CostAction1174ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://fusion-id.uswitch.com/b9xj3w?apiKey=QUYetZCrcOfSoyjbsudb&version=3&loaderVersion=3.12.2 | 319ms | 265ms | 8ms | 3rd |
| Unattributable | 297ms | 63ms | 0ms | 3rd |
| https://www.uswitch.com/broadband/ | 241ms | 19ms | 21ms | 1st |
| https://www.uswitch.com/s3/uswitch-includes-production/includes/astro/_astro/index.astro_astro_type_script_index_0_lang.BwRyypT4.js | 132ms | 97ms | 1ms | 1st |
| https://www.uswitch.com/s3/uswitch-assets-eu/builder/q-BZuR-q1Y.js | 72ms | 60ms | 0ms | 1st |
| https://www.uswitch.com/s3/uswitch-assets-eu/broadband-frontend/_astro/client.CnKqq7uk.js | 58ms | 41ms | 0ms | 1st |
| https://www.uswitch.com/s3/uswitch-assets-eu/builder/q-DwXy33lI.js | 55ms | 55ms | 0ms | 1st |
CJS BundlesAction270 scripts, 203 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.uswitch.com/s3/uswitch-includes-production/includes/astro/_astro/index.astro_astro_type_script_index_0_lang.BwRyypT4.js | 115 KB | 88 KB (76%) | ✓ | 1st |
| https://www.uswitch.com/s3/uswitch-includes-production/js/main-060f15b567.js | 79 KB | 44 KB (56%) | ✓ | 1st |
| https://www.uswitch.com/s3/uswitch-assets-eu/broadband-frontend/_astro/index.C0_vgsVJ.js | 31 KB | 26 KB (84%) | ✓ | 1st |
| https://www.uswitch.com/s3/uswitch-assets-eu/builder/q-vZ0_Q8YH.js | 27 KB | 22 KB (83%) | ✓ | 1st |
| https://www.uswitch.com/s3/uswitch-assets-eu/broadband-frontend/_astro/client.CnKqq7uk.js | 56 KB | 22 KB (39%) | ✓ | 1st |
| https://www.uswitch.com/s3/uswitch-assets-eu/broadband-frontend/_astro/page.BNtUc4G9.js | 1 KB | — | ✓ | 1st |
| https://www.uswitch.com/s3/uswitch-assets-eu/broadband-frontend/_astro/ExpandableIntro.astro_astro_type_script_index_0_lang.CRX6EDj5.js | 1 KB | — | ✓ | 1st |
| https://www.uswitch.com/s3/uswitch-assets-eu/broadband-frontend/_astro/Header.astro_astro_type_script_index_0_lang.Bqtnph2e.js | 1 KB | — | ✓ | 1st |
| https://www.uswitch.com/s3/uswitch-assets-eu/broadband-frontend/_astro/Modal.astro_astro_type_script_index_0_lang.DKrsTOTo.js | 1 KB | — | ✓ | 1st |
| https://www.uswitch.com/s3/uswitch-assets-eu/broadband-frontend/_astro/AddressModal.astro_astro_type_script_index_0_lang.TNdpPfOG.js | 1 KB | — | ✓ | 1st |
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
BHTTP/3 (QUIC)HTTP/3 not advertisedREVIEW
CCompression AlgorithmActionMain response served uncompressedREVIEW
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
BHTTP Cachingmax-age=0, must-revalidateREVIEW
max-age=0, must-revalidate
| Directive | Value | Meaning |
|---|---|---|
| max-age | 0 | Cache for 0 seconds |
| must-revalidate | — | Must recheck with server after expiry |
AThird-Party Impact26% third-party, 0 ms blockingPASS
A+Text CompressionAll text resources are compressedPASS
A+Font Loading1 fonts (36 KB)PASS
Web fonts
1
36 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
A+LCP Image PreloadLCP preload audit not availablePASS
A+Main HTML Cache-ControlMain HTML max-age=0 (≤ 5min) is appropriatePASS
A+Server-Timing Observability2 Server-Timing entries advertisedPASS
A+Server Response Intelligence1 server-response signal(s) detectedPASS
Network Waterfall343 requests over 1980msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
fusion-id.uswitch.com fusion-id.uswitch.com | Other | 319ms | 64 KB | — | €2/mo | Costly |
Unattributable Unattributable | Other | 297ms | 0 KB | — | €2/mo | Costly |
These scripts may cost more than they're worth
- fusion-id.uswitch.com adds 319ms and costs ~€2/month
- Unattributable adds 297ms and costs ~€2/month
52% of JavaScript execution time comes from third-party scripts.
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
fusion-id.uswitch.com takes 319ms 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 297ms 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
Real-User Performance (CrUX)Field metrics from the Chrome User Experience ReportINFO
Chrome User Experience (CrUX)
Real-user metrics from the Chrome UX Report (2026-04-11 — 2026-05-08)
LCP (p75)
964 ms
95% good
INP (p75)
163 ms
83% good
CLS (p75)
0.000
99% good
FCP (p75)
919 ms
TTFB (p75)
511 ms