Performance
· 23 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.
646 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
2.27 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
10 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.008
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
1.46 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.
2.30 s
Page Load Progression
FPage Weight BudgetAction3.4 MB transferred, 134 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
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
CJS Execution CostAction1581ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.campusone.co.uk/ | 830ms | 4ms | 9ms | 1st |
| https://www.campusone.co.uk/_next/static/chunks/0v5ii6_5p1xpg.js | 342ms | 186ms | 7ms | 1st |
| Unattributable | 209ms | 12ms | 0ms | 1st |
| https://www.campusone.co.uk/_next/static/chunks/1vykdafo07ed6.js | 128ms | 90ms | 4ms | 1st |
| https://www.googletagmanager.com/gtag/js?id=G-EJ2HEWMTPG&cx=c>m=4e6as1 | 73ms | 59ms | 12ms | 3rd |
CJS BundlesAction29 scripts, 201 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtag/js?id=G-EJ2HEWMTPG&cx=c>m=4e6as1 | 177 KB | 75 KB (42%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-TM6SGRS4 | 124 KB | 62 KB (50%) | ✓ | 3rd |
| https://www.campusone.co.uk/_next/static/chunks/0e6skt-2hu0zv.js | 39 KB | 38 KB (100%) | ✓ | 1st |
| https://www.campusone.co.uk/_next/static/chunks/0v5ii6_5p1xpg.js | 70 KB | 27 KB (38%) | ✓ | 1st |
| https://www.campusone.co.uk/_next/static/chunks/2lnb_udw2_n-1.js | 5 KB | — | ✓ | 1st |
| https://cdn.cmpstack.io/cmpstack-ui.js?v=b45d0cd3 | 14 KB | — | ✓ | 3rd |
| https://www.campusone.co.uk/_next/static/chunks/turbopack-2noawjncj7c7z.js | 4 KB | — | ✓ | 1st |
| https://www.campusone.co.uk/_next/static/chunks/0oz66_9wndt57.js | 4 KB | — | ✓ | 1st |
| https://www.campusone.co.uk/_next/static/chunks/430yp0jar2a2m.js | 6 KB | — | ✓ | 1st |
| https://www.campusone.co.uk/_next/static/chunks/3_hvllj5rf9uy.js | 10 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
BMain HTML Cache-ControlCache-Control present but without max-ageREVIEW
BServer-Timing ObservabilityNo Server-Timing header foundREVIEW
CPage Weight InventoryAction134 resources · 3.4 MB · 201 KB savings availableREVIEW
~201.3 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 134 resources | 3.4 MiB | ||||||
BHTTP Cachings-maxage=3600, stale-while-revalidate=31532400REVIEW
s-maxage=3600, stale-while-revalidate=31532400
| Directive | Value | Meaning |
|---|---|---|
| s-maxage | 3600 | CDN caches for 1 hour |
| stale-while-revalidate | 31532400 | Serve stale for 52 weeks while fetching fresh |
A+Third-Party Impact9% third-party, 0 ms blockingPASS
A+Text CompressionAll text resources are compressedPASS
AImage Optimization27 images, 0 KB saveablePASS
A+Font Loading5 fonts (342 KB)PASS
Web fonts
5
342 KB total
Render-blocking
0
of 5
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+HTTP/3 (QUIC)HTTP/3 advertised via Alt-SvcPASS
A+Document CompressionDocument response uses brotliPASS
A+LCP Image PreloadLCP preload audit not availablePASS
A+Server Response Intelligence2 server-response signal(s) detectedPASS
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
This site is hosted on green energy infrastructure
Provider: Cloudflare
Asset CompressionNo text asset hosts to measureINFO
Network Waterfall134 requests over 2357msINFO
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 | 177 KB | 42% | £1/mo | Optional |
Image Optimization42 images, 830 KB total, 497 KB wastedINFO
Image Optimization Audit
Total Images
42
Total Size
830 KB
Oversized
3
Wasted
497 KB