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Performance

· 26 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
94
GRADE
A
FIX
1
REVIEW
5
PASS
17
INFO
3

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

Mobile Desktop
99
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
58
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
88
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
82
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

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

904 ms

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

1.95 s

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.

0.031

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

1.01 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.

1.95 s

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
26
17 PASS 5 REVIEW 1 FIX
F
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
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.

B
HTTP/3 (QUIC)
HTTP/3 not advertised
REVIEW
HTTP/3 not advertised
Info::
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::
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::
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::
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+
Page Weight Budget
103 KB transferred, 5 requests
PASS
103 KB transferred, 5 requests
Info::
Page weighs 106 KB (103 KB transferred)
Info::
5 HTTP requests
Info::
Estimated 0.02 g CO2 per page load
103 KB / 2.4 MB budget
103 KB transferred
5 requests
0.02 g CO2 per page load
Images 99.9 KiB 97%
HTML 2.0 KiB 2%
CSS 1.0 KiB 1%
Other 499 B 0%
0 2.4 MB 4.9 MB
Under budget
A+
Third-Party Impact
No third-party resources
PASS
No third-party resources
Info::
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
Info::
All text resources are compressed
All text resources are properly compressed.
A
Image Optimization
2 images, 0 KB saveable
PASS
2 images, 0 KB saveable
Warning::
https://start.mmuszynski.com/DSC_1580.jpg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
2 images 100 KB
0 oversized -0 KB
2 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

A+
JS Execution Cost
82ms total JS execution
PASS
82ms total JS execution
Info::
Unattributable: 82ms CPU time
Warning::
Third-party scripts: 82ms (100% of total)

Main Thread Breakdown

Other 68% Style & Layout 13% Script Evaluation 11% Rendering 4%
ScriptTotalScriptingParse/CompileParty
Unattributable82ms5ms0ms3rd
A+
Font Loading
No web fonts (system fonts)
PASS
No web fonts (system fonts)
Info::
No web fonts loaded — system fonts are fastest
No web fonts loaded — system fonts are optimal.
A+
JS Bundles
No JavaScript
PASS
No JavaScript
Info::
No JavaScript bundles
No JavaScript files loaded.
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
2 server-response signal(s) detected
PASS
2 server-response signal(s) detected
Info::
`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).
Info::
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.
A+
Page Weight Inventory
5 resources · 103 KB · 0 KB savings available
PASS
5 resources · 103 KB · 0 KB savings available
Info::
Within 1MB page-weight target
Got: 103 KB
5 resources · 103.4 KiB · 0 third-party Within 1MB page-weight target
Image 97% · 99.9 KiB
Document 2% · 2.5 KiB
CSS 1% · 1.0 KiB
A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
A+
JavaScript Blocking
No render-blocking JS or document.write usage detected
PASS
No render-blocking JS or document.write usage detected
Info::
No JavaScript blocking issues detected
A+
CSS Performance Depth
No CSS performance depth issues detected
PASS
No CSS performance depth issues detected
Info::
No CSS performance depth issues detected
Network Waterfall
5 requests over 768ms
INFO
0 ms 500 ms 1.0 s 1.5 s 2.0 s FCP 904 ms LCP 2.0 shttps://start.mmuszynski.com// https://start.mmuszynski.com/ — 200 — 2.0 KiB — 287 ms — http/1.1https://start.mmuszynski.com/style.css/style.css https://start.mmuszynski.com/style.css — 200 — 1.0 KiB — 95 ms — http/1.1https://start.mmuszynski.com/DSC_1580.jpg/DSC_1580.jpg https://start.mmuszynski.com/DSC_1580.jpg — 200 — 99.6 KiB — 372 ms — http/1.1https://start.mmuszynski.com/body_back.gif/body_back.gif https://start.mmuszynski.com/body_back.gif — 404 — 283 B — 96 ms — http/1.1https://start.mmuszynski.com/favicon.ico/favicon.ico https://start.mmuszynski.com/favicon.ico — 404 — 499 B — 187 ms — http/1.1
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
100% of JavaScript execution is third-party
First-party Third-party 82ms · 0KB · $1/mo
Unattributable
Other
Optional
Execution 82ms
Transfer 0 KB
Monthly Cost $1/mo

100% 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

How third-party costs are calculated

Image Optimization
1 images, 208 KB total, 0 KB wasted
INFO

Image Optimization Audit

Total Images

1

Total Size

208 KB

1 missing alt text 1 missing dimensions
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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