Performance

· 26 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.

SCORE

GRADE

A+

FIX

REVIEW

PASS

INFO

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

Performance

100

Accessibility

100

Best Practices

SEO

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

3.51 s

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

3.51 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.

0.000

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

3.51 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.

3.51 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

20 PASS 4 REVIEW

JS Execution Cost

840ms total JS execution

REVIEW

840ms total JS execution

https://vision-ai-3am9.onrender.com/: 546ms CPU time

Unattributable: 294ms CPU time

Main Thread Breakdown

Other 34% Script Evaluation 26% Style & Layout 22% Parse HTML & CSS 7% Script Parsing & Compilation 6% Rendering 3%

Script	Total	Scripting	Parse/Compile	Party
https://vision-ai-3am9.onrender.com/	546ms	94ms	42ms	1st
Unattributable	294ms	83ms	0ms	1st

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

no-cache

REVIEW

no-cache

Cache-Control header is set

Got: no-cache

ETag present — enables conditional (304) responses

Last-Modified header present

Cache-Control

no-cache

Directive	Value	Meaning
no-cache	—	Cache but always revalidate first

A+

Page Weight Budget

287 KB transferred, 20 requests

PASS

287 KB transferred, 20 requests

Page weighs 609 KB (287 KB transferred)

20 HTTP requests

Estimated 0.06 g CO2 per page load

287 KB transferred

20 requests

0.06 g CO2 per page load

HTML 124.3 KiB 43%

Other 48.5 KiB 17%

Fonts 47.3 KiB 17%

JavaScript 35.7 KiB 12%

Images 22.7 KiB 8%

Other 4.2 KiB 1%

CSS 2.5 KiB 1%

Other 1.3 KiB 0%

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 (85.5 KiB of 286.5 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

1 images, 0 KB saveable

PASS

1 images, 0 KB saveable

All images are well-optimized

1 images 23 KB

0 oversized -0 KB

0 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)

UcC73FwrK3iLTeHuS_nVMrM... woff2 swap

Size 47 KB

Load time 67 ms

Start 532 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+

JS Bundles

8 scripts, 0 KB unused

PASS

8 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/marked@15.0.12/marked.min.js	13 KB	—	✓	3rd
https://cdnjs.cloudflare.com/ajax/libs/dompurify/3.1.5/purify.min.js	8 KB	—	✓	3rd
https://cdnjs.cloudflare.com/ajax/libs/prism/1.29.0/prism.min.js	6 KB	—	✓	3rd
https://cdnjs.cloudflare.com/ajax/libs/prism/1.29.0/components/prism-python.min.js	1 KB	—	✓	3rd
https://cdnjs.cloudflare.com/ajax/libs/prism/1.29.0/components/prism-javascript.min.js	2 KB	—	✓	3rd
https://cdnjs.cloudflare.com/ajax/libs/prism/1.29.0/components/prism-bash.min.js	3 KB	—	✓	3rd
https://cdnjs.cloudflare.com/ajax/libs/prism/1.29.0/components/prism-css.min.js	1 KB	—	✓	3rd
https://cdnjs.cloudflare.com/ajax/libs/prism/1.29.0/components/prism-markup.min.js	1 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

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+

Asset Compression

All 1 asset host use brotli

PASS

All 1 asset host use brotli

cdnjs.cloudflare.com serves assets with brotli (assets: 9)

Got: cdnjs.cloudflare.com (application/javascript)

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 uses no-cache -- safe revalidate-on-request policy

PASS

Main HTML uses no-cache -- safe revalidate-on-request policy

Got: no-cache

A+

Server Response Intelligence

2 server-response signal(s) detected

PASS

2 server-response signal(s) detected

`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).

Both `ETag` and `Last-Modified` present -- efficient revalidation supported

The page returns both `ETag` (content hash) and `Last-Modified` (timestamp) headers. Browsers can issue conditional GETs with `If-None-Match` or `If-Modified-Since`; the server returns 304 Not Modified for unchanged content, saving bandwidth. ETag is the more reliable of the two (timestamps fail in DST transitions and clock skew).

A+

Page Weight Inventory

20 resources · 287 KB · 0 KB savings available

PASS

20 resources · 287 KB · 0 KB savings available

Within 1MB page-weight target

Got: 287 KB

11 third-party resources (30% of weight)

20 resources · 286.5 KiB · 11 third-party Within 1MB page-weight target

Document 43% · 124.3 KiB

Image 25% · 71.2 KiB

Font 17% · 47.3 KiB

JavaScript 12% · 35.7 KiB

Other 2% · 5.6 KiB

CSS 1% · 2.5 KiB

#	Resource	Type	Size	Cache	Unused	3rd party	Issues

20 resources			286.5 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

2 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

Network Waterfall

20 requests over 2392ms

INFO

HTML JavaScript CSS Images Fonts XHR/Fetch Other

Image Optimization

3 images, 68 KB total, 22 KB wasted

INFO

Image Optimization Audit

Total Images

Total Size

68 KB

Oversized

Wasted

22 KB

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