Performance

· 21 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

Performance

Accessibility

100

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.

693 ms

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

751 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.

695 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.

754 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

10 PASS 8 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.

No Cache-Control header

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

Page Weight Budget

Action

1.6 MB transferred, 17 requests

REVIEW

1.6 MB transferred, 17 requests

Page weighs 2.0 MB (1.6 MB transferred)

Images are 1.3 MB — compress or use modern formats

Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.

Got: 1.3 MB

Fonts are 255 KB — consider subsetting or using system fonts

Subset fonts to include only used characters, or switch to system font stacks.

Got: 255 KB

17 HTTP requests

Estimated 0.34 g CO2 per page load

1.6 MB transferred

17 requests

0.34 g CO2 per page load

Images 1.3 MiB 79%

Fonts 254.9 KiB 16%

CSS 56.1 KiB 3%

JavaScript 24.7 KiB 2%

HTML 6.2 KiB 0%

Other 0 B 0%

0 2.4 MB 4.9 MB

Approaching limit

Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.

Why this matters

Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.

Source: web.dev

Subset fonts to include only used characters, or switch to system font stacks.

Why this matters

Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).

Source: web.dev font loading

Image Optimization

6 images, 0 KB saveable

REVIEW

6 images, 0 KB saveable

https://dealsbrokers.pl/logo.png is missing width/height — may cause layout shift

Set explicit width and height to prevent CLS.

6 images 1.3 MB

0 oversized -0 KB

4 legacy format

1 missing dimensions CLS risk

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

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.

Compression Algorithm

Action

Main response served uncompressed

REVIEW

Main response served uncompressed

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.

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.

Page Weight Inventory

Action

17 resources · 1.6 MB · 0 KB savings available

REVIEW

17 resources · 1.6 MB · 0 KB savings available

Page weight 1.6 MB exceeds 1 MB target by 614 KB

Got: 1.6 MB Expected: ≤ 1 MB

10 third-party resources (20% of weight)

3 resources over 200KB

17 resources · 1.6 MiB · 10 third-party 613.8 KiB over 1MB target

Image 79% · 1.3 MiB

Font 16% · 254.9 KiB

CSS 3% · 56.1 KiB

JavaScript 2% · 24.7 KiB

Document 0% · 6.2 KiB

#	Resource	Type	Size	Cache	Unused	3rd party	Issues

17 resources			1.6 MiB

Green Hosting

Action

Whether the site is served from green-energy infrastructure

REVIEW

Green Hosting

No green hosting detected

Third-Party Impact

20% third-party, 0 ms blocking

PASS

20% third-party, 0 ms blocking

Third-party code accounts for 20% of page weight (332.6 KiB of 1.6 MiB)

Third-party blocking time is low (0 ms)

80%

20%

First-party Third-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

110ms total JS execution

PASS

110ms total JS execution

https://dealsbrokers.pl/: 110ms CPU time

Main Thread Breakdown

Other 41% Style & Layout 40% Rendering 8% Parse HTML & CSS 5% Script Evaluation 5%

Script	Total	Scripting	Parse/Compile	Party
https://dealsbrokers.pl/	110ms	1ms	0ms	1st

A+

Font Loading

3 fonts (255 KB)

PASS

3 fonts (255 KB)

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

Web fonts

255 KB total

Render-blocking

of 3

Dominant font-display

swap

Most common across fonts

Font loading timeline

Transfer FOIT (block) FOUT (swap)

JTUSjIg1_i6t8kCHKm459Wl... woff2 swap

Size 35 KB

Load time 49 ms

Start 398 ms

Risk FOUT — text flashes from fallback to web font

fa-solid-900.woff2 woff2 swap

Size 154 KB

Load time 69 ms

Start 398 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

JTUSjIg1_i6t8kCHKm459Wd... woff2 swap

Size 67 KB

Load time 64 ms

Start 399 ms

Risk FOUT — 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)

Fixing the unchecked items could save ~77 KB and ~154 ms

A+

JS Bundles

1 scripts, 0 KB unused

PASS

1 scripts, 0 KB unused

0 KB unused JavaScript

Downloaded but never executed on this page.

Script	Size	Unused	Minified	Party
https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/js/bootstrap.bundle.min.js	25 KB	—	✓	3rd

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+

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: User-Agent

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).

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

17 requests over 688ms

INFO

HTML JavaScript CSS Images Fonts XHR/Fetch Other

Image Optimization

3 images, 36 KB total, 11 KB wasted

INFO

Image Optimization Audit

Total Images

Total Size

36 KB

Oversized

Wasted

11 KB

2 missing dimensions 2 missing lazy loading

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