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

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.

468 ms

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

766 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.

468 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.

770 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

16 PASS 3 REVIEW

JS Bundles

3 scripts, 73 KB unused

REVIEW

3 scripts, 73 KB unused

https://www.googletagmanager.com/gtag/js?id=G-XE1F...: 73 KB unused (42%)

Consider code splitting or tree shaking to reduce unused code.

Total unused JavaScript: 73 KB

73 KB unused JavaScript

Downloaded but never executed on this page.

Script	Size	Unused	Minified	Party
https://www.googletagmanager.com/gtag/js?id=G-XE1FVB6MSP	176 KB	73 KB (42%)	✓	3rd
https://stocktostove.com/_astro/page.DDsIKVU2.js	2 KB	—	✓	1st
https://stocktostove.com/_astro/IngredientPicker.astro_astro_type_script_index_0_lang.CW-bq8Jk.js	4 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

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.

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

596 KB transferred, 23 requests

PASS

596 KB transferred, 23 requests

Page weighs 1.2 MB (596 KB transferred)

23 HTTP requests

Estimated 0.12 g CO2 per page load

596 KB transferred

23 requests

0.12 g CO2 per page load

Images 252.6 KiB 42%

JavaScript 182.6 KiB 31%

Other 71.1 KiB 12%

Fonts 52.4 KiB 9%

HTML 16.3 KiB 3%

CSS 10.8 KiB 2%

Other 9.9 KiB 2%

0 2.4 MB 4.9 MB

Under budget

Third-Party Impact

30% third-party, 0 ms blocking

PASS

30% third-party, 0 ms blocking

Third-party code accounts for 30% of page weight (176.9 KiB of 595.7 KiB)

Third-party blocking time is low (0 ms)

70%

30%

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+

Image Optimization

11 images, 0 KB saveable

PASS

11 images, 0 KB saveable

All images are well-optimized

11 images 253 KB

0 oversized -0 KB

0 legacy format

0 missing dimensions CLS risk

A+

JS Execution Cost

125ms total JS execution

PASS

125ms total JS execution

https://stocktostove.com/: 70ms CPU time

https://www.googletagmanager.com/gtag/js?id=G-XE1F...: 55ms CPU time

Third-party scripts: 55ms (44% of total)

Main Thread Breakdown

Other 33% Script Evaluation 33% Style & Layout 22% Script Parsing & Compilation 6% Rendering 3% Parse HTML & CSS 3%

Script	Total	Scripting	Parse/Compile	Party
https://stocktostove.com/	70ms	5ms	2ms	1st
https://www.googletagmanager.com/gtag/js?id=G-XE1FVB6MSP	55ms	46ms	9ms	3rd

A+

Font Loading

2 fonts (52 KB)

PASS

2 fonts (52 KB)

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

Web fonts

52 KB total

Render-blocking

of 2

Dominant font-display

swap

Most common across fonts

Font loading timeline

Transfer FOIT (block) FOUT (swap)

502b9851e13aed9b.woff2 woff2 swap

Size 29 KB

Load time 51 ms

Start 99 ms

Risk FOUT — text flashes from fallback to web font

181a29443484632f.woff2 woff2 swap

Size 23 KB

Load time 27 ms

Start 178 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

No optimization needed

PASS

No optimization needed

No resource hint issues

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.

A+

Page Weight Inventory

23 resources · 596 KB · 73 KB savings available

PASS

23 resources · 596 KB · 73 KB savings available

Within 1MB page-weight target

Got: 596 KB

~73 KB of savings available

2 third-party resources (30% of weight)

23 resources · 595.7 KiB · 2 third-party Within 1MB page-weight target

Image 44% · 261.6 KiB

JavaScript 31% · 182.6 KiB

Other 12% · 71.1 KiB

Font 9% · 52.4 KiB

Document 3% · 17.2 KiB

CSS 2% · 10.8 KiB

~73.4 KiB of savings available

Remove unused JavaScript: 73.4 KiB

#	Resource	Type	Size	Cache	Unused	3rd party	Issues

23 resources			595.7 KiB

A+

Green Hosting

Whether the site is served from green-energy infrastructure

PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Cloudflare

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

23 requests over 718ms

INFO

HTML JavaScript CSS Images Fonts XHR/Fetch Other

Third-Party Script Cost

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

INFO

44% of JavaScript execution is third-party

First-party Third-party 55ms · 176KB · €1/mo

Script	Category	Execution	Transfer	Unused	Monthly Cost	Verdict
Google Tag Manager www.googletagmanager.com	Tag Manager	55ms	176 KB	42%	€1/mo	Optional

Google Tag Manager

Tag Manager

Optional

Execution 55ms

Transfer 176 KB

Unused 42%

Monthly Cost €1/mo

44% 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

How third-party costs are calculated

Image Optimization

12 images, 195 KB total, 0 KB wasted

INFO

Image Optimization Audit

Total Images

Total Size

195 KB

4 missing lazy loading

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