Performance
· 24 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.
389 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.48 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
98 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.161
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
1.87 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.
3.55 s
Page Load Progression
FPage Weight BudgetAction3.1 MB transferred, 168 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
Subset fonts to include only used characters, or switch to system font stacks.
Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).
Source: web.dev font loading
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
FJS BundlesAction62 scripts, 600 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.lycamobile.co.uk/_next/static/chunks/pages/_app-eaa6432c8502f70f.js | 490 KB | 252 KB (52%) | ✓ | 1st |
| https://www.googletagmanager.com/gtag/js?id=G-P52E9JTP7V&cx=c>m=4e6au1 | 197 KB | 75 KB (38%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-WRQNFFFZ | 127 KB | 61 KB (48%) | ✓ | 3rd |
| https://www.lycamobile.co.uk/_next/static/chunks/24141-9b521af344399d83.js | 48 KB | 43 KB (93%) | ✓ | 1st |
| https://www.lycamobile.co.uk/_next/static/chunks/65524-fe97f2b637723349.js | 37 KB | 33 KB (95%) | ✓ | 1st |
| https://assets.adobedtm.com/9007b98fe545/821c9abd597c/launch-acb171025420.min.js | 152 KB | 33 KB (22%) | ✓ | 3rd |
| https://www.lycamobile.co.uk/_next/static/chunks/40366-10825ec590c80a79.js | 35 KB | 30 KB (91%) | ✓ | 1st |
| https://www.lycamobile.co.uk/_next/static/chunks/framework-25500088d8b22498.js | 69 KB | 27 KB (40%) | ✓ | 1st |
| https://www.lycamobile.co.uk/_next/static/chunks/55160-299f4560e73a3227.js | 30 KB | 23 KB (80%) | ✓ | 1st |
| https://www.lycamobile.co.uk/_next/static/chunks/main-e30ada0fb6f9f3ed.js | 43 KB | 22 KB (53%) | ✓ | 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
FPage Weight InventoryAction168 resources · 3.1 MB · 600 KB savings availableFIX
~599.9 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 168 resources | 3.1 MiB | ||||||
DHTTP CachingActionno-store (uncacheable)FIX
private, no-cache, no-store, max-age=0, must-revalidate
| Directive | Value | Meaning |
|---|---|---|
| private | — | Only browser cache, not CDN/proxy |
| no-cache | — | Cache but always revalidate first |
| no-store | — | Never cache this response |
| max-age | 0 | Cache for 0 seconds |
| must-revalidate | — | Must recheck with server after expiry |
BThird-Party Impact49% third-party, 0 ms blockingREVIEW
CImage OptimizationAction49 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
CJS Execution CostAction1157ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.lycamobile.co.uk/_next/static/chunks/framework-25500088d8b22498.js | 362ms | 307ms | 4ms | 1st |
| https://www.lycamobile.co.uk/_next/static/chunks/pages/_app-eaa6432c8502f70f.js | 140ms | 87ms | 49ms | 1st |
| Unattributable | 139ms | 2ms | 0ms | 1st |
| https://www.lycamobile.co.uk/en/ | 111ms | 8ms | 1ms | 1st |
| https://www.lycamobile.co.uk/cdn-cgi/challenge-platform/scripts/jsd/main.js?ray=a54b4a37ebb945bc | 77ms | 69ms | 1ms | 1st |
| https://www.googletagmanager.com/gtag/js?id=G-P52E9JTP7V&cx=c>m=4e6au1 | 73ms | 62ms | 11ms | 3rd |
| https://assets.adobedtm.com/9007b98fe545/821c9abd597c/launch-acb171025420.min.js | 72ms | 52ms | 18ms | 3rd |
| https://www.lycamobile.co.uk/_next/static/chunks/94085.8c630b3ee8f3defb.js | 68ms | 58ms | 0ms | 1st |
| https://scripts.clarity.ms/0.8.77-beta/clarity.js | 63ms | 57ms | 1ms | 3rd |
| https://www.lycamobile.co.uk/_next/static/chunks/24141-9b521af344399d83.js | 53ms | 47ms | 3ms | 1st |
BServer-Timing ObservabilityNo Server-Timing header foundREVIEW
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 Loading6 fonts (280 KB)PASS
Web fonts
6
280 KB total
Render-blocking
0
of 6
Dominant font-display
swap
Most common across fonts
Font loading timeline
- Convert to woff2 for ~30% smaller file size
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 ~1 KB and ~2 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
A+HTTP/3 (QUIC)HTTP/3 advertised via Alt-SvcPASS
A+Document CompressionDocument response uses brotliPASS
A+LCP Image PreloadLCP preload audit not availablePASS
A+Main HTML Cache-ControlMain HTML uses no-store -- correct for sensitive/dynamic contentPASS
A+Server Response Intelligence2 server-response signal(s) detectedPASS
Asset CompressionNo text asset hosts to measureINFO
Network Waterfall168 requests over 2886msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Google Tag Manager www.googletagmanager.com | Tag Manager | 73ms | 197 KB | 38% | £1/mo | Optional |
assets.adobedtm.com assets.adobedtm.com | Other | 72ms | 152 KB | 22% | £1/mo | Optional |
Microsoft Clarity scripts.clarity.ms | Session Replay | 63ms | 25 KB | — | £1/mo | Optional |
Real-User Performance (CrUX)Field metrics from the Chrome User Experience ReportINFO
Chrome User Experience (CrUX)
Real-user metrics from the Chrome UX Report (2026-10-05 — 2026-11-01)
LCP (p75)
1925 ms
82% good
INP (p75)
247 ms
65% good
CLS (p75)
0.320
34% good
FCP (p75)
1251 ms
TTFB (p75)
691 ms
Image Optimization100 images, 4 KB total, 0 KB wastedINFO
Image Optimization Audit
Total Images
100
Total Size
4 KB
Oversized
17