Performance
· 26 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.
4.17 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
18.20 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
4.02 s
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.819
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
7.55 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.
23.48 s
Page Load Progression
FPage Weight BudgetAction3.6 MB transferred, 227 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
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
DJS BundlesAction145 scripts, 464 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://static.files.bbci.co.uk/core/bundle-simple-promo-collection.7487668c9c88284679ed.js | 3 KB | 90 KB (65%) | ✓ | 3rd |
| https://mybbc-analytics.files.bbci.co.uk/echo-client-js/echo-2.6.0-avi.min.js | 117 KB | 57 KB (49%) | ✓ | 3rd |
| https://static.files.bbci.co.uk/core/bundle-component-quick-user-actions-menu.d1504c979cb5440fe9e9.js | 10 KB | 48 KB (84%) | ✓ | 3rd |
| https://static.files.bbci.co.uk/core/bundle-portrait-video-experience.5dfe8f712a3db2c864cc.js | 5 KB | 45 KB (89%) | ✓ | 3rd |
| https://static.files.bbci.co.uk/core/bundle-component-hierarchical-promo-collection.4150874175bf451cf5cf.js | 4 KB | 45 KB (33%) | ✓ | 3rd |
| https://static.files.bbci.co.uk/core/bundle-global-footer.a01bbf845c6c88d47cd6.js | 1 KB | 41 KB (58%) | ✓ | 3rd |
| https://static.files.bbci.co.uk/core/bundle-hierarchical-promo-collection.2bc8e09275ffe6cc4fc9.js | 2 KB | 36 KB (100%) | ✓ | 3rd |
| https://static.files.bbci.co.uk/core/bundle-component-promo-with-ranking.eccdbc4feddf4af34a17.js | 4 KB | 28 KB (40%) | ✓ | 3rd |
| https://static.files.bbci.co.uk/core/bundle-component-simple-promo-collection.afee1a61fca6c3a1e491.js | 5 KB | 27 KB (79%) | ✓ | 3rd |
| https://static.files.bbci.co.uk/core/bundle-component-live-preview-promo.190e2784770904f0fae6.js | 4 KB | 24 KB (62%) | ✓ | 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 InventoryAction227 resources · 3.6 MB · 464 KB savings availableFIX
~464.5 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 227 resources | 3.6 MiB | ||||||
BImage Optimization47 images, 0 KB saveableREVIEW
CDocument CompressionActionDocument response served uncompressedREVIEW
CMain HTML Cache-ControlActionMain HTML max-age=604800 (~10080min) is aggressiveREVIEW
BServer-Timing ObservabilityNo Server-Timing header foundREVIEW
BJavaScript Blocking1 JS blocking issue(s) detectedREVIEW
A+Text CompressionAll text resources are compressedPASS
A+JS Execution CostNo JS execution dataPASS
A+Font Loading8 fonts (517 KB)PASS
Web fonts
8
517 KB total
Render-blocking
0
of 8
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
AResource Hints10 hints, 0 missing preconnectsPASS
Current Resource Hints
10 resource hints configured
Each preconnect eagerly opens a TCP+TLS connection. On slow networks or low-end devices, too many parallel connections cause head-of-line blocking and starve the connections that matter for LCP. Trim to the 4-6 highest-value origins (the ones serving render-blocking or LCP resources).
Informational: a labeled value pair from the audit.
A+HTTP/3 (QUIC)HTTP/3 advertised via Alt-SvcPASS
AAsset Compression1 of 2 asset hosts still on gzipPASS
A+LCP Image PreloadLCP preload audit not availablePASS
A+Server Response Intelligence1 server-response signal(s) detectedPASS
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
A+Third-Party ResourcesNo third-party resources detectedPASS
ACSS Performance Depth1 CSS depth issue(s) detectedPASS
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
This site is hosted on green energy infrastructure
Provider: Fastly
AHTTP Cachingmax-age=604800 (1 week)PASS
public,max-age=604800,stale-while-revalidate=3600,stale-if-error=3600
| Directive | Value | Meaning |
|---|---|---|
| public | — | Any cache may store this response |
| max-age | 604800 | Cache for 1 week |
| stale-while-revalidate | 3600 | Serve stale for 1 hour while fetching fresh |
| stale-if-error | 3600 |
Network Waterfall227 requests over 3185msINFO
Image Optimization137 images, 80 KB total, 0 KB wastedINFO
Image Optimization Audit
Total Images
137
Total Size
80 KB