Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
C
Page Weight Budget
Action
1.6 MB transferred, 47 requests
REVIEW
1.6 MB transferred, 47 requests
Info::
i
Page weighs 3.2 MB (1.6 MB transferred)
Warning::
!
JavaScript is 793 KB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 793 KB
Info::
✓
47 HTTP requests
Info::
i
Estimated 0.34 g CO2 per page load
1.6 MBtransferred
47 requests
0.34 g CO2 per page load
JavaScript793.2 KiB48%
Images523.7 KiB32%
Fonts156.8 KiB10%
Other101.0 KiB6%
CSS44.6 KiB3%
HTML25.9 KiB2%
Other755 B0%
Other551 B0%
02.4 MB4.9 MB
Approaching limit
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Why this matters
JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.
Source: web.dev
C
Image Optimization
Action
21 images, 0 KB saveable
REVIEW
21 images, 0 KB saveable
Warning::
!
is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.analvids.com/assets/img/agree18/analvi... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.analvids.com/assets/img/logo/analvids.... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
21images524 KB
0oversized-0 KB
19legacy format
3missing dimensionsCLS risk
Set explicit width and height to prevent CLS.
Why this matters
Performance issues directly impact user engagement and conversion rates.
Set explicit width and height to prevent CLS.
Why this matters
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.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
B
HTTP/3 (QUIC)
HTTP/3 not advertised
REVIEW
HTTP/3 not advertised
Info::
i
HTTP/3 (QUIC) is not advertised
HTTP/3 isn't advertised via Alt-Svc and the worker didn't negotiate h3. HTTP/3 reduces handshake latency (1-RTT instead of 2-3 RTTs) and is more resilient on lossy connections. Most modern CDNs (Cloudflare, Fastly, AWS CloudFront, Google Cloud CDN) support HTTP/3 with a single config switch -- consider enabling for mobile-heavy workloads.
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
Main HTML Cache-Control
No Cache-Control header on main HTML response
REVIEW
No Cache-Control header on main HTML response
Info::
i
Main HTML response has no Cache-Control header
Without an explicit Cache-Control, browsers fall back to heuristic caching (~10% of Last-Modified age). Set `Cache-Control: no-cache` or `max-age=300` for HTML to control freshness explicitly -- prevents stale auth state and SPA shell drift.
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.
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW
Green Hosting
No green hosting detected
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+
JS Execution Cost
469ms total JS execution
PASS
469ms total JS execution
Info::
i
https://www.analvids.com/assets/js/app.js?rev=815: 168ms CPU time
Info::
i
Unattributable: 109ms CPU time
Info::
i
https://www.analvids.com/: 78ms CPU time
Info::
i
https://www.googletagmanager.com/gtag/js?id=G-K7TR...: 61ms CPU time
Info::
i
https://www.gstatic.com/recaptcha/releases/rL1ELiQ...: 53ms CPU time
4 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
4
157 KB total
Render-blocking
0
of 4
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
lato-v17-latin-regular....woff2swap
Size23 KB
Load time40 ms
Start275 ms
RiskFOUT — text flashes from fallback to web font
lato-v17-latin-700.woff2woff2swap
Size23 KB
Load time76 ms
Start276 ms
RiskFOUT — text flashes from fallback to web font
lato-v17-latin-900.woff2woff2swap
Size22 KB
Load time93 ms
Start276 ms
RiskFOUT — text flashes from fallback to web font
bootstrap-icons.woff2woff2swap
Size89 KB
Load time122 ms
Start277 ms
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+
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+
Server Response Intelligence
1 server-response signal(s) detected
PASS
1 server-response signal(s) detected
Info::
i
No `ETag` or `Last-Modified` -- conditional GET not supported
Without either header, browsers can't issue conditional GETs and refresh always re-downloads the full response body even when nothing changed. Add `ETag: "<hash>"` (or `Last-Modified: <date>`) on cacheable responses; the server returns 304 Not Modified when the client's cached copy is still valid, saving bandwidth.
Network Waterfall
47 requests over 949ms
INFO
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
77%of JavaScript execution is third-party
First-party Third-party360ms · 663KB · Kč44/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
www.analvids.com
www.analvids.com
Other
168ms
107 KB
70%
Kč21/mo
Optional
www.analvids.com
www.analvids.com
Other
78ms
26 KB
—
Kč10/mo
Optional
Google Tag Manager
www.googletagmanager.com
Tag Manager
61ms
155 KB
45%
Kč8/mo
Optional
www.gstatic.com
www.gstatic.com
Other
53ms
375 KB
66%
Kč6/mo
Optional
www.analvids.com
Other
Optional
Execution168ms
Transfer107 KB
Unused70%
Monthly CostKč21/mo
www.analvids.com
Other
Optional
Execution78ms
Transfer26 KB
Monthly CostKč10/mo
Google Tag Manager
Tag Manager
Optional
Execution61ms
Transfer155 KB
Unused45%
Monthly CostKč8/mo
www.gstatic.com
Other
Optional
Execution53ms
Transfer375 KB
Unused66%
Monthly CostKč6/mo
77% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
Why this matters
When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.
Learn more ▾▴
Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.
Source: web.dev
70% of www.analvids.com's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
66% of www.gstatic.com's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.