Consider code splitting or tree shaking to reduce unused code.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
C
Compression Algorithm
Action
Main response served uncompressed
REVIEW
Main response served uncompressed
Info::
i
Main HTML response has no Content-Encoding (uncompressed)
The main HTML document is served without compression. The Text Compression section above lists the broader picture; for the main response specifically, even gzip would shave ~70-80% off most text payloads.
B
Server-Timing Observability
No Server-Timing header found
REVIEW
No Server-Timing header found
Info::
i
No Server-Timing header found
Server-Timing exposes backend timing breakdowns to browser DevTools (e.g., `db: 45ms; render: 120ms; cache: 2ms`). Useful for diagnosing slow pages without backend log access. Most modern frameworks (Next.js, Cloudflare Workers, Fastly) emit it automatically; absence on a managed platform usually means telemetry headers are stripped at the edge.
Whether the site is served from green-energy infrastructure
REVIEW
Green Hosting
No green hosting detected
A
Page Weight Budget
937 KB transferred, 78 requests
PASS
937 KB transferred, 78 requests
Info::
✓
Page weighs 2.5 MB (937 KB transferred)
Info::
i
78 HTTP requests
Info::
i
Estimated 0.19 g CO2 per page load
937 KBtransferred
78 requests
0.19 g CO2 per page load
JavaScript476.5 KiB51%
Images261.9 KiB28%
Fonts108.2 KiB12%
HTML63.0 KiB7%
CSS24.5 KiB3%
Other910 B0%
Other806 B0%
Other715 B0%
Other559 B0%
02.4 MB4.9 MB
Under budget
A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
✓
All text resources are compressed
All text resources are properly compressed.
A
Image Optimization
25 images, 0 KB saveable
PASS
25 images, 0 KB saveable
Info::
✓
All images are well-optimized
25images86 KB
0oversized-0 KB
3legacy format
0missing dimensionsCLS risk
A+
Font Loading
12 fonts (108 KB)
PASS
12 fonts (108 KB)
Info::
i
12 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
12
108 KB total
Render-blocking
0
of 12
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
subset-AvenirLTStd-Heav...woff2swap
Size10 KB
Load time395 ms
Start988 ms
RiskFOUT — text flashes from fallback to web font
subset-Avenir-Roman.woff2woff2swap
Size18 KB
Load time396 ms
Start988 ms
RiskFOUT — text flashes from fallback to web font
subset-Avenir-Oblique.w...woff2swap
Size16 KB
Load time401 ms
Start989 ms
RiskFOUT — text flashes from fallback to web font
subset-Avenir-Black.woff2woff2swap
Size17 KB
Load time354 ms
Start1.0 s
RiskFOUT — text flashes from fallback to web font
subset-Avenir-Heavy.woff2woff2swap
Size17 KB
Load time355 ms
Start1.0 s
RiskFOUT — text flashes from fallback to web font
subset-Avenir-Medium.woff2woff2swap
Size30 KB
Load time537 ms
Start1.0 s
RiskFOUT — text flashes from fallback to web font
subset-AvenirLTStd-Heav...woff2swap
Size0 KB
Load time0 ms
Start1.8 s
RiskFOUT — text flashes from fallback to web font
subset-Avenir-Roman.woff2woff2swap
Size0 KB
Load time0 ms
Start1.8 s
RiskFOUT — text flashes from fallback to web font
subset-Avenir-Oblique.w...woff2swap
Size0 KB
Load time0 ms
Start1.8 s
RiskFOUT — text flashes from fallback to web font
subset-Avenir-Black.woff2woff2swap
Size0 KB
Load time0 ms
Start2.1 s
RiskFOUT — text flashes from fallback to web font
subset-Avenir-Medium.woff2woff2swap
Size0 KB
Load time0 ms
Start2.1 s
RiskFOUT — text flashes from fallback to web font
subset-Avenir-Heavy.woff2woff2swap
Size0 KB
Load time0 ms
Start2.1 s
RiskFOUT — text flashes from fallback to web font
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 Caching
All resources properly cached
PASS
All resources properly cached
Info::
✓
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
✓
No render-blocking resources detected
A+
Resource Hints
No optimization needed
PASS
No optimization needed
Info::
✓
No resource hint issues
A+
HTTP/3 (QUIC)
HTTP/3 advertised via Alt-Svc
PASS
HTTP/3 advertised via Alt-Svc
Info::
✓
HTTP/3 (QUIC) is supported
First-load mobile users on cellular networks see meaningful latency improvements with HTTP/3. The QUIC transport collapses TLS + TCP handshakes into one and recovers faster from packet loss.
A+
LCP Image Preload
LCP preload audit not available
PASS
LCP preload audit not available
Info::
✓
LCP image preload audit not available for this scan
A+
Main HTML Cache-Control
Main HTML uses no-store -- correct for sensitive/dynamic content
PASS
Main HTML uses no-store -- correct for sensitive/dynamic content
Info::
✓
Main HTML uses no-store -- correct for sensitive/dynamic content
The page declares a `Vary` header, telling downstream caches which request headers the response varies on. Critical for content-negotiated responses (compression, language, cookies, device class).
Info::
✓
`ETag` present -- conditional GET supported
Network Waterfall
78 requests over 2983ms
INFO
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
46%of JavaScript execution is third-party
First-party Third-party309ms · 325KB · £5/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
Unattributable
Unattributable
Other
120ms
0 KB
—
£2/mo
Optional
Google Tag Manager
www.googletagmanager.com
Tag Manager
99ms
175 KB
40%
£1/mo
Optional
Google Tag Manager
www.googletagmanager.com
Tag Manager
91ms
150 KB
43%
£1/mo
Optional
Unattributable
Other
Optional
Execution120ms
Transfer0 KB
Monthly Cost£2/mo
Google Tag Manager
Tag Manager
Optional
Execution99ms
Transfer175 KB
Unused40%
Monthly Cost£1/mo
Google Tag Manager
Tag Manager
Optional
Execution91ms
Transfer150 KB
Unused43%
Monthly Cost£1/mo
46% of JavaScript execution time comes from third-party scripts.
Why this matters
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.