Performance

· 23 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.

SCORE

GRADE

FIX

REVIEW

PASS

INFO

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop

100

Performance

Accessibility

Best Practices

100

SEO

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

324 ms

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

384 ms

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

0 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.000

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

406 ms

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

386 ms

Page Load Progression

375 ms

750 ms

1.1 s

1.5 s

1.9 s

2.2 s

2.6 s

3.0 s

Checks

13 PASS 5 REVIEW 1 FIX

HTTP Caching

Action

No cache headers

FIX

No cache headers

No Cache-Control header found

Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.

ETag present — enables conditional (304) responses

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

Image Optimization

9 images, 0 KB saveable

REVIEW

9 images, 0 KB saveable

All images are well-optimized

9 images 167 KB

0 oversized -0 KB

6 legacy format

0 missing dimensions CLS risk

HTTP/3 (QUIC)

HTTP/3 not advertised

REVIEW

HTTP/3 not advertised

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.

Main HTML Cache-Control

No Cache-Control header on main HTML response

REVIEW

No Cache-Control header on main HTML response

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.

Server-Timing Observability

No Server-Timing header found

REVIEW

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.

Green Hosting

Action

Whether the site is served from green-energy infrastructure

REVIEW

Green Hosting

No green hosting detected

A+

Page Weight Budget

429 KB transferred, 16 requests

PASS

429 KB transferred, 16 requests

Page weighs 846 KB (429 KB transferred)

16 HTTP requests

Estimated 0.09 g CO2 per page load

429 KB transferred

16 requests

0.09 g CO2 per page load

Fonts 177.9 KiB 41%

Images 167.5 KiB 39%

CSS 63.8 KiB 15%

HTML 16.0 KiB 4%

Other 1.6 KiB 0%

Other 1.4 KiB 0%

Other 608 B 0%

0 2.4 MB 4.9 MB

Under budget

A+

Third-Party Impact

No third-party resources

PASS

No third-party resources

No third-party resources detected

No third-party resources detected — all resources are first-party.

A+

Text Compression

All text resources are compressed

PASS

All text resources are compressed

All text resources are properly compressed.

A+

JS Execution Cost

70ms total JS execution

PASS

70ms total JS execution

https://ztorbynauczycielki.pl/: 70ms CPU time

Main Thread Breakdown

Other 36% Style & Layout 31% Script Evaluation 13% Parse HTML & CSS 13% Rendering 6%

Script	Total	Scripting	Parse/Compile	Party
https://ztorbynauczycielki.pl/	70ms	12ms	1ms	1st

A+

Font Loading

2 fonts (178 KB)

PASS

2 fonts (178 KB)

2 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

178 KB total

Render-blocking

of 2

Dominant font-display

swap

Most common across fonts

Font loading timeline

Transfer FOIT (block) FOUT (swap)

fa-regular-400.woff2 woff2 swap

Size 25 KB

Load time 55 ms

Start 322 ms

Risk FOUT — text flashes from fallback to web font

fa-solid-900.woff2 woff2 swap

Size 153 KB

Load time 105 ms

Start 323 ms

Risk FOUT — text flashes from fallback to web font

Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need

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 ~76 KB and ~152 ms

A+

JS Bundles

No JavaScript

PASS

No JavaScript

No JavaScript bundles

No JavaScript files loaded.

A+

Resource Caching

All resources properly cached

PASS

All resources properly cached

No caching issues found

All static resources have appropriate caching headers.

A+

Critical Rendering Path

No render-blocking resources

PASS

No render-blocking resources

No render-blocking resources detected

A+

Resource Hints

No optimization needed

PASS

No optimization needed

No resource hint issues

A+

Document Compression

Document response uses brotli

PASS

Document response uses brotli

Main HTML response uses brotli (Content-Encoding: br)

Brotli is the best text-compression algorithm for general use, ~20% smaller than gzip on average (40% on smaller files). Modern browsers all support it.

A+

LCP Image Preload

LCP preload audit not available

PASS

LCP preload audit not available

LCP image preload audit not available for this scan

A+

Server Response Intelligence

2 server-response signal(s) detected

PASS

2 server-response signal(s) detected

`Vary` header declared: Accept-Encoding

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).

`ETag` present -- conditional GET supported

A+

Page Weight Inventory

16 resources · 429 KB · 0 KB savings available

PASS

16 resources · 429 KB · 0 KB savings available

Within 1MB page-weight target

Got: 429 KB

3 third-party resources (0% of weight)

16 resources · 428.7 KiB · 3 third-party Within 1MB page-weight target

Font 41% · 177.9 KiB

Image 39% · 169.0 KiB

CSS 15% · 63.8 KiB

Document 4% · 17.4 KiB

Other 0% · 608 B

#	Resource	Type	Size	Cache	Unused	3rd party	Issues

16 resources			428.7 KiB

Asset Compression

No text asset hosts to measure

INFO

No text asset hosts to measure

No third-party or subdomain host served enough text assets to measure

Asset compression is measured per host, from one HEAD request against a sampled resource. Pages that serve all their JS and CSS from the document's own origin are covered by the document compression check instead.

Network Waterfall

16 requests over 498ms

INFO

HTML JavaScript CSS Images Fonts XHR/Fetch Other

Real-User Performance (CrUX)

Field metrics from the Chrome User Experience Report

INFO

Chrome User Experience (CrUX)

Real-user metrics from the Chrome UX Report (2026-09-25 — 2026-10-22)

LCP (p75)

795 ms

97% good

INP (p75)

53 ms

98% good

CLS (p75)

0.000

99% good

FCP (p75)

719 ms

TTFB (p75)

506 ms

This origin passes Core Web Vitals assessment

Image Optimization

10 images, 137 KB total, 0 KB wasted

INFO

Image Optimization Audit

Total Images

Total Size

137 KB

3 missing lazy loading

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.