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Performance

· 25 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
89
GRADE
B
FIX
1
REVIEW
7
PASS
15
INFO
2

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.
93
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
96
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
100
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.

913 ms

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

1.25 s

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

124 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.

913 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.

1.75 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
25
15 PASS 7 REVIEW 1 FIX
F
Page Weight Budget
Action
2.8 MB transferred, 17 requests
FIX
2.8 MB transferred, 17 requests
Warning::
Page weighs 3.2 MB (2.8 MB transferred)
Warning::
Images are 2.7 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 2.7 MB
Info::
17 HTTP requests
Info::
Estimated 0.59 g CO2 per page load
2.8 MB / 2.4 MB budget
2.8 MB transferred
17 requests
0.59 g CO2 per page load
Images 2.7 MiB 94%
JavaScript 141.5 KiB 5%
Other 6.2 KiB 0%
CSS 4.4 KiB 0%
HTML 4.2 KiB 0%
Other 3.3 KiB 0%
0 2.4 MB 4.9 MB
Over budget

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

B
JS Execution Cost
989ms total JS execution
REVIEW
989ms total JS execution
Warning::
https://yishi99.netlify.app/contact: 336ms CPU time
Warning::
https://yishi99.netlify.app/_next/static/chunks/07...: 330ms CPU time
Warning::
Unattributable: 256ms CPU time
Info::
https://yishi99.netlify.app/_next/static/chunks/0d...: 68ms CPU time
Info::
Third-party scripts: 256ms (26% of total)

Main Thread Breakdown

Script Evaluation 38% Style & Layout 27% Other 25% Script Parsing & Compilation 8%
ScriptTotalScriptingParse/CompileParty
https://yishi99.netlify.app/contact336ms7ms8ms1st
https://yishi99.netlify.app/_next/static/chunks/07lhk_q6pmm3r.js330ms295ms31ms1st
Unattributable256ms20ms0ms3rd
https://yishi99.netlify.app/_next/static/chunks/0dha171epf-bp.js68ms41ms18ms1st
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
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
Page Weight Inventory
Action
17 resources · 2.8 MB · 27 KB savings available
REVIEW
17 resources · 2.8 MB · 27 KB savings available
Warning::
Page weight 2.8 MB exceeds 1 MB target by 1.8 MB
Got: 2.8 MB Expected: ≤ 1 MB
Info::
2 resources over 200KB
17 resources · 2.8 MiB · 0 third-party 1.8 MiB over 1MB target
Image 94% · 2.7 MiB
JavaScript 5% · 141.5 KiB
Document 0% · 7.6 KiB
Other 0% · 6.1 KiB
CSS 0% · 4.4 KiB

~27.5 KiB of savings available

Remove unused JavaScript: 27.5 KiB
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

B
HTTP Caching
public,max-age=0,must-revalidate
REVIEW
public,max-age=0,must-revalidate
Info::
Cache-Control header is set
Got: public,max-age=0,must-revalidate
Info::
ETag present — enables conditional (304) responses
Cache-Control

public,max-age=0,must-revalidate

DirectiveValueMeaning
public—Any cache may store this response
max-age0Cache for 0 seconds
must-revalidate—Must recheck with server after expiry
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
Info::
All images are well-optimized
2 images 2.7 MB
0 oversized -0 KB
2 legacy format
0 missing dimensions CLS risk
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
7 scripts, 27 KB unused
PASS
7 scripts, 27 KB unused
Warning::
https://yishi99.netlify.app/_next/static/chunks/07...: 27 KB unused (41%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 27 KB
27 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://yishi99.netlify.app/_next/static/chunks/07lhk_q6pmm3r.js67 KB27 KB (41%)✓1st
https://yishi99.netlify.app/_next/static/chunks/0p8tu7idk~nwx.js9 KB—✓1st
https://yishi99.netlify.app/_next/static/chunks/0pqt~8bl3ukh4.js9 KB—✓1st
https://yishi99.netlify.app/_next/static/chunks/0dha171epf-bp.js36 KB—✓1st
https://yishi99.netlify.app/_next/static/chunks/turbopack-01cdivxh8p84x.js4 KB—✓1st
https://yishi99.netlify.app/_next/static/chunks/0m6ou.ufw-o4f.js4 KB—✓1st
https://yishi99.netlify.app/_next/static/chunks/0d3shmwh5_nmn.js12 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

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
1 hints, 0 missing preconnects
PASS
1 hints, 0 missing preconnects
Info::
Page uses 1 resource hint(s)

Current Resource Hints

preconnect
—
preload
1
dns-prefetch
—
prefetch
—

1 resource hints configured

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+
Main HTML Cache-Control
Main HTML max-age=0 (≤ 5min) is appropriate
PASS
Main HTML max-age=0 (≤ 5min) is appropriate
Info::
Main HTML max-age=0 (≤ 5min) is appropriate
Got: public,max-age=0,must-revalidate
A+
Server Response Intelligence
3 server-response signal(s) detected
PASS
3 server-response signal(s) detected
Info::
`Cache-Status` header present (RFC 9211): "Netlify Edge"; hit
The page returns a `Cache-Status` header -- the standardized way for CDNs and caches to communicate per-hop cache state to debugging tools. Format: `Cache-Status: cdn-name; hit; ttl=300` (or `; fwd=miss` / `; fwd=stale`). Standard alternative to vendor-specific `X-Cache` patterns each CDN had historically. Cloudflare, Fastly, and Akamai all support emitting it.
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::
`ETag` present -- conditional GET supported
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
1 JS blocking issue(s) detected
PASS
1 JS blocking issue(s) detected
Warning::
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
Info::
No CSS performance depth issues detected
Network Waterfall
17 requests over 714ms
INFO
0 ms 500 ms 1.0 s FCP 913 ms LCP 1.3 shttps://yishi99.netlify.app/contact/contact https://yishi99.netlify.app/contact — 200 — 4.2 KiB — 12 ms — h2https://yishi99.netlify.app/_next/static/chunks/184ais~emt2-j.css/_next/static/chunks/184ais~emt2-j.... https://yishi99.netlify.app/_next/static/chunks/184ais~emt2-j.css — 200 — 4.4 KiB — 7 ms — h2https://yishi99.netlify.app/_next/static/chunks/0p8tu7idk~nwx.js/_next/static/chunks/0p8tu7idk~nwx.... https://yishi99.netlify.app/_next/static/chunks/0p8tu7idk~nwx.js — 200 — 8.9 KiB — 13 ms — h2https://yishi99.netlify.app/_next/static/chunks/0pqt~8bl3ukh4.js/_next/static/chunks/0pqt~8bl3ukh4.... https://yishi99.netlify.app/_next/static/chunks/0pqt~8bl3ukh4.js — 200 — 8.7 KiB — 15 ms — h2https://yishi99.netlify.app/_next/static/chunks/07lhk_q6pmm3r.js/_next/static/chunks/07lhk_q6pmm3r.... https://yishi99.netlify.app/_next/static/chunks/07lhk_q6pmm3r.js — 200 — 66.9 KiB — 24 ms — h2https://yishi99.netlify.app/_next/static/chunks/0dha171epf-bp.js/_next/static/chunks/0dha171epf-bp.... https://yishi99.netlify.app/_next/static/chunks/0dha171epf-bp.js — 200 — 36.2 KiB — 20 ms — h2https://yishi99.netlify.app/_next/static/chunks/turbopack-01cdivxh8p84x.js/_next/static/chunks/turbopack-01cd... https://yishi99.netlify.app/_next/static/chunks/turbopack-01cdivxh8p84x.js — 200 — 4.0 KiB — 12 ms — h2https://yishi99.netlify.app/_next/static/chunks/0m6ou.ufw-o4f.js/_next/static/chunks/0m6ou.ufw-o4f.... https://yishi99.netlify.app/_next/static/chunks/0m6ou.ufw-o4f.js — 200 — 4.5 KiB — 11 ms — h2https://yishi99.netlify.app/_next/static/chunks/0d3shmwh5_nmn.js/_next/static/chunks/0d3shmwh5_nmn.... https://yishi99.netlify.app/_next/static/chunks/0d3shmwh5_nmn.js — 200 — 12.2 KiB — 28 ms — h2https://yishi99.netlify.app/favicon.ico/favicon.ico https://yishi99.netlify.app/favicon.ico — 404 — 3.3 KiB — 5 ms — h2https://yishi99.netlify.app// https://yishi99.netlify.app/ — 200 — 111 B — 9 ms — h2https://yishi99.netlify.app/__next._tree.txt?_rsc=h2vb-LAkAGynSY5z/__next._tree.txt?_rsc=h2vb-LAkAGyn... https://yishi99.netlify.app/__next._tree.txt?_rsc=h2vb-LAkAGynSY5z — 200 — 448 B — 221 ms — h2https://yishi99.netlify.app/images/stretch-film.png/images/stretch-film.png https://yishi99.netlify.app/images/stretch-film.png — 200 — 1.4 MiB — 242 ms — h2https://yishi99.netlify.app/images/flat-bag.png/images/flat-bag.png https://yishi99.netlify.app/images/flat-bag.png — 200 — 1.2 MiB — 193 ms — h2https://yishi99.netlify.app/__next._head.txt?_rsc=Edh1o4O2g_TGZBR9/__next._head.txt?_rsc=Edh1o4O2g_TG... https://yishi99.netlify.app/__next._head.txt?_rsc=Edh1o4O2g_TGZBR9 — 200 — 1.0 KiB — 18 ms — h2https://yishi99.netlify.app/__next._index.txt?_rsc=60m9ttaXtJHZmEpN/__next._index.txt?_rsc=60m9ttaXtJH... https://yishi99.netlify.app/__next._index.txt?_rsc=60m9ttaXtJHZmEpN — 200 — 1.5 KiB — 18 ms — h2https://yishi99.netlify.app/__next.__PAGE__.txt?_rsc=00jsNgvC9sZ9uZS6/__next.__PAGE__.txt?_rsc=00jsNgvC9... https://yishi99.netlify.app/__next.__PAGE__.txt?_rsc=00jsNgvC9sZ9uZS6 — 200 — 3.1 KiB — 27 ms — h2
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
26% of JavaScript execution is third-party
First-party Third-party 256ms · 0KB · $3/mo
Unattributable
Other
Costly
Execution 256ms
Transfer 0 KB
Monthly Cost $3/mo

These scripts may cost more than they're worth

  • Unattributable adds 256ms and costs ~$3/month

Unattributable takes 256ms 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.

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