Performance

· 26 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.

957 ms

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

1.26 s

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

151 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.

957 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.

3.66 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

17 PASS 6 REVIEW

Third-Party Impact

55% third-party, 0 ms blocking

REVIEW

55% third-party, 0 ms blocking

Third-party code accounts for 55% of page weight (189.2 KiB of 344.7 KiB)

Third-party blocking time is low (0 ms)

45%

55%

First-party Third-party

JS Execution Cost

655ms total JS execution

REVIEW

655ms total JS execution

https://www.googletagmanager.com/gtag/js?id=G-7CVV...: 267ms CPU time

Unattributable: 149ms CPU time

https://math-kit.pages.dev/: 142ms CPU time

https://math-kit.pages.dev/_astro/client.3KfiIzy5....: 97ms CPU time

Third-party scripts: 267ms (41% of total)

Main Thread Breakdown

Script Evaluation 52% Other 24% Style & Layout 12% Script Parsing & Compilation 8%

Script	Total	Scripting	Parse/Compile	Party
https://www.googletagmanager.com/gtag/js?id=G-7CVV9WMFET	267ms	216ms	47ms	3rd
Unattributable	149ms	14ms	0ms	1st
https://math-kit.pages.dev/	142ms	18ms	6ms	1st
https://math-kit.pages.dev/_astro/client.3KfiIzy5.js	97ms	87ms	0ms	1st

JS Bundles

10 scripts, 107 KB unused

REVIEW

10 scripts, 107 KB unused

https://www.googletagmanager.com/gtag/js?id=G-7CVV...: 73 KB unused (41%)

Consider code splitting or tree shaking to reduce unused code.

https://math-kit.pages.dev/_astro/client.3KfiIzy5....: 34 KB unused (52%)

Consider code splitting or tree shaking to reduce unused code.

Total unused JavaScript: 107 KB

107 KB unused JavaScript

Downloaded but never executed on this page.

Script	Size	Unused	Minified	Party
https://www.googletagmanager.com/gtag/js?id=G-7CVV9WMFET	177 KB	73 KB (41%)	✓	3rd
https://math-kit.pages.dev/_astro/client.3KfiIzy5.js	65 KB	34 KB (52%)	✓	1st
https://math-kit.pages.dev/theme-init.js	1 KB	—	✓	1st
https://static.cloudflareinsights.com/beacon.min.js	10 KB	—	✓	3rd
https://math-kit.pages.dev/_astro/LiveSearch.CZWxge3v.js	1 KB	—	✓	1st
https://math-kit.pages.dev/_astro/ThemeToggle.BZbGTRGI.js	1 KB	—	✓	1st
https://math-kit.pages.dev/_astro/MobileNav.C_seHRlB.js	2 KB	—	✓	1st
https://math-kit.pages.dev/_astro/react.yIOJJ3r4.js	4 KB	—	✓	1st
https://math-kit.pages.dev/_astro/jsx-runtime.DvU585tb.js	1 KB	—	✓	1st
https://math-kit.pages.dev/_astro/LiveSearch.BgTyN37S.js	11 KB	—	✓	1st

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

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

HTTP Caching

public, max-age=0, must-revalidate

REVIEW

public, max-age=0, must-revalidate

Cache-Control header is set

Got: public, max-age=0, must-revalidate

No ETag or Last-Modified header

Conditional requests (304 Not Modified) are not possible without validators.

Cache-Control

public, max-age=0, must-revalidate

Directive	Value	Meaning
public	—	Any cache may store this response
max-age	0	Cache for 0 seconds
must-revalidate	—	Must recheck with server after expiry

A+

Page Weight Budget

345 KB transferred, 21 requests

PASS

345 KB transferred, 21 requests

Page weighs 976 KB (345 KB transferred)

21 HTTP requests

Estimated 0.07 g CO2 per page load

345 KB transferred

21 requests

0.07 g CO2 per page load

JavaScript 272.5 KiB 79%

Fonts 47.5 KiB 14%

HTML 9.9 KiB 3%

CSS 7.9 KiB 2%

Other 4.9 KiB 1%

Other 1.1 KiB 0%

Other 560 B 0%

Images 408 B 0%

Other 35 B 0%

Other 0 B 0%

0 2.4 MB 4.9 MB

Under budget

A+

Text Compression

All text resources are compressed

PASS

All text resources are compressed

All text resources are properly compressed.

A+

Image Optimization

1 images, 0 KB saveable

PASS

1 images, 0 KB saveable

All images are well-optimized

1 images 0 KB

0 oversized -0 KB

1 legacy format

0 missing dimensions CLS risk

A+

Font Loading

1 fonts (47 KB)

PASS

1 fonts (47 KB)

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

Web fonts

47 KB total

Render-blocking

of 1

Dominant font-display

swap

Most common across fonts

Font loading timeline

Transfer FOIT (block) FOUT (swap)

inter-var-latin.woff2 woff2 swap

Size 47 KB

Load time 44 ms

Start 119 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)

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

1 hints, 0 missing preconnects

PASS

1 hints, 0 missing preconnects

Page uses 1 resource hint(s)

Current Resource Hints

preconnect

—

preload

dns-prefetch

—

prefetch

—

1 resource hints configured

A+

HTTP/3 (QUIC)

HTTP/3 advertised via Alt-Svc

PASS

HTTP/3 advertised via Alt-Svc

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+

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+

Main HTML Cache-Control

Main HTML max-age=0 (≤ 5min) is appropriate

PASS

Main HTML max-age=0 (≤ 5min) is appropriate

Got: public, max-age=0, must-revalidate

Server Response Intelligence

2 server-response signal(s) detected

PASS

2 server-response signal(s) detected

Compressed response missing `Vary` header

The page is served with `Content-Encoding: br` but has no `Vary` header. Without `Vary: Accept-Encoding`, intermediary caches (corporate proxies, ISP caches) may serve the compressed variant to clients that didn't send the matching `Accept-Encoding` -- the client sees garbled bytes. Add `Vary: Accept-Encoding` whenever the response is conditionally compressed.

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.

Page Weight Inventory

21 resources · 345 KB · 107 KB savings available

PASS

21 resources · 345 KB · 107 KB savings available

Within 1MB page-weight target

Got: 345 KB

~107 KB of savings available

7 third-party resources (55% of weight)

21 resources · 344.7 KiB · 7 third-party Within 1MB page-weight target

JavaScript 79% · 272.5 KiB

Font 14% · 47.5 KiB

Document 3% · 9.9 KiB

CSS 2% · 7.9 KiB

Other 2% · 5.5 KiB

Image 0% · 1.5 KiB

~106.8 KiB of savings available

Remove unused JavaScript: 106.8 KiB

#	Resource	Type	Size	Cache	Unused	3rd party	Issues

21 resources			344.7 KiB

A+

Render-Blocking Resources

No render-blocking resources detected

PASS

No render-blocking resources detected

No render-blocking resources detected in <head>

A+

Third-Party Resources

No third-party resources detected

PASS

No third-party resources detected

JavaScript Blocking

1 JS blocking issue(s) detected

PASS

1 JS blocking issue(s) detected

1 render-blocking <script src> tag(s) without async/defer

Each `<script src=...>` without `async`, `defer`, or `type="module"` blocks HTML parsing while the browser fetches and executes it. The block lasts the entire round-trip + execution time -- on slow networks this translates directly into LCP delay. Add `defer` (executes after parse, in source order) for scripts that interact with the DOM, or `async` (executes whenever ready) for analytics / independent scripts. Module scripts (`type="module"`) are deferred by default.

A+

CSS Performance Depth

No CSS performance depth issues detected

PASS

No CSS performance depth issues detected

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

21 requests over 654ms

INFO

HTML JavaScript CSS Images Fonts XHR/Fetch Other

Third-Party Script Cost

Per-script blocking time, transfer cost, and cache headers

INFO

41% of JavaScript execution is third-party

First-party Third-party 267ms · 177KB · €4/mo

Script	Category	Execution	Transfer	Unused	Monthly Cost	Verdict
Google Tag Manager www.googletagmanager.com	Tag Manager	267ms	177 KB	41%	€4/mo	Costly

Google Tag Manager

Tag Manager

Costly

Execution 267ms

Transfer 177 KB

Unused 41%

Monthly Cost €4/mo

These scripts may cost more than they're worth

Google Tag Manager adds 267ms and costs ~€4/month

41% 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.

Source: web.dev / HTTP Archive Web Almanac

Google Tag Manager takes 267ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

How third-party costs are calculated

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