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Performance

· 23 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
94
GRADE
A
FIX
0
REVIEW
3
PASS
16
INFO
4

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.
94
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
100
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.

647 ms

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

885 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.

692 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.

885 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
23
16 PASS 3 REVIEW
B
JS Bundles
4 scripts, 73 KB unused
REVIEW
4 scripts, 73 KB unused
Warning::
https://www.googletagmanager.com/gtag/js?id=G-FN9H...: 73 KB unused (41%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 73 KB
73 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.googletagmanager.com/gtag/js?id=G-FN9H4RKMSJ177 KB73 KB (41%)✓3rd
https://aicost.tools/_astro/SearchModal.astro_astro_type_script_index_0_lang.C3j1IxmM.js2 KB—✓1st
https://earlylaunch.co/widget/1e211b2b-5d2d-400f-898a-32c44314c7fb/script.js2 KB—✓3rd
https://aicost.tools/_astro/engine.B1YIArAN.js1 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

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.
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::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
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+
Page Weight Budget
548 KB transferred, 16 requests
PASS
548 KB transferred, 16 requests
Info::
Page weighs 1.0 MB (548 KB transferred)
Info::
Fonts are 326 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 326 KB
Info::
16 HTTP requests
Info::
Estimated 0.11 g CO2 per page load
548 KB / 2.4 MB budget
548 KB transferred
16 requests
0.11 g CO2 per page load
Fonts 325.9 KiB 60%
JavaScript 183.2 KiB 33%
HTML 17.6 KiB 3%
CSS 12.1 KiB 2%
Other 6.3 KiB 1%
Images 1.3 KiB 0%
Other 792 B 0%
Other 545 B 0%
0 2.4 MB 4.9 MB
Under budget

Subset fonts to include only used characters, or switch to system font stacks.

Why this matters

Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).

Source: web.dev font loading

A
Third-Party Impact
33% third-party, 0 ms blocking
PASS
33% third-party, 0 ms blocking
Info::
Third-party code accounts for 33% of page weight (181.4 KiB of 547.7 KiB)
Info::
Third-party blocking time is low (0 ms)
67%
33%
First-party Third-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::
is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
2 images 1 KB
0 oversized -0 KB
1 legacy format
1 missing dimensions CLS risk

Set explicit width and height to prevent CLS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

A+
JS Execution Cost
209ms total JS execution
PASS
209ms total JS execution
Info::
https://aicost.tools/: 149ms CPU time
Info::
https://www.googletagmanager.com/gtag/js?id=G-FN9H...: 60ms CPU time
Info::
Third-party scripts: 60ms (29% of total)

Main Thread Breakdown

Style & Layout 42% Other 25% Script Evaluation 20% Rendering 6% Script Parsing & Compilation 4%
ScriptTotalScriptingParse/CompileParty
https://aicost.tools/149ms3ms1ms1st
https://www.googletagmanager.com/gtag/js?id=G-FN9H4RKMSJ60ms50ms9ms3rd
A+
Font Loading
4 fonts (326 KB)
PASS
4 fonts (326 KB)
Info::
4 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

4

326 KB total

Render-blocking

0

of 4

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s FCP 647 ms LCP 885 mshttps://aicost.tools/fonts/fraunces-normal-latin.woff2fraunces-normal-latin.w... https://aicost.tools/fonts/fraunces-normal-latin.woff2 — 118.7 KiB — 98 ms — font-display: swaphttps://aicost.tools/fonts/fraunces-italic-latin.woff2fraunces-italic-latin.w... https://aicost.tools/fonts/fraunces-italic-latin.woff2 — 146.8 KiB — 114 ms — font-display: swaphttps://aicost.tools/fonts/jetbrainsmono-normal-latin.woff2jetbrainsmono-normal-la... https://aicost.tools/fonts/jetbrainsmono-normal-latin.woff2 — 31.2 KiB — 119 ms — font-display: swaphttps://aicost.tools/fonts/geist-normal-latin.woff2geist-normal-latin.woff2 https://aicost.tools/fonts/geist-normal-latin.woff2 — 29.2 KiB — 90 ms — font-display: swap
fraunces-normal-latin.w... woff2 swap
Size 119 KB
Load time 98 ms
Start 235 ms
Risk FOUT — text flashes from fallback to web font
  • Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
fraunces-italic-latin.w... woff2 swap
Size 147 KB
Load time 114 ms
Start 235 ms
Risk FOUT — text flashes from fallback to web font
  • Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
jetbrainsmono-normal-la... woff2 swap
Size 31 KB
Load time 119 ms
Start 236 ms
Risk FOUT — text flashes from fallback to web font
geist-normal-latin.woff2 woff2 swap
Size 29 KB
Load time 90 ms
Start 487 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)

Fixing the unchecked items could save ~133 KB and ~266 ms

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+
HTTP/3 (QUIC)
HTTP/3 advertised via Alt-Svc
PASS
HTTP/3 advertised via Alt-Svc
Info::
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
Info::
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
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
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
16 resources · 548 KB · 73 KB savings available
PASS
16 resources · 548 KB · 73 KB savings available
Info::
Within 1MB page-weight target
Got: 548 KB
Info::
~73 KB of savings available
Info::
4 third-party resources (33% of weight)
16 resources · 547.7 KiB · 4 third-party Within 1MB page-weight target
Font 60% · 325.9 KiB
JavaScript 33% · 183.2 KiB
Document 3% · 17.6 KiB
CSS 2% · 12.1 KiB
Image 1% · 7.6 KiB
Other 0% · 1.3 KiB

~73.0 KiB of savings available

Remove unused JavaScript: 73.0 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
Info::
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
16 requests over 791ms
INFO
0 ms 200 ms 400 ms 600 ms 800 ms FCP 647 ms LCP 885 mshttps://aicost.tools// https://aicost.tools/ — 200 — 17.6 KiB — 226 ms — h3https://www.googletagmanager.com/gtag/js?id=G-FN9H4RKMSJwww.googletagmanager.com/gtag/js?id... https://www.googletagmanager.com/gtag/js?id=G-FN9H4RKMSJ — 200 — 177.1 KiB — 398 ms — h2https://aicost.tools/fonts/fraunces-normal-latin.woff2/fonts/fraunces-normal-latin.woff2 https://aicost.tools/fonts/fraunces-normal-latin.woff2 — 200 — 118.7 KiB — 98 ms — h3https://aicost.tools/fonts/fraunces-italic-latin.woff2/fonts/fraunces-italic-latin.woff2 https://aicost.tools/fonts/fraunces-italic-latin.woff2 — 200 — 146.8 KiB — 114 ms — h3https://aicost.tools/fonts/jetbrainsmono-normal-latin.woff2/fonts/jetbrainsmono-normal-latin.w... https://aicost.tools/fonts/jetbrainsmono-normal-latin.woff2 — 200 — 31.2 KiB — 119 ms — h3https://aicost.tools/_astro/Base.xACOz3Uc.css/_astro/Base.xACOz3Uc.css https://aicost.tools/_astro/Base.xACOz3Uc.css — 200 — 7.5 KiB — 165 ms — h3https://aicost.tools/_astro/index.CDcIbIbF.css/_astro/index.CDcIbIbF.css https://aicost.tools/_astro/index.CDcIbIbF.css — 200 — 4.6 KiB — 104 ms — h3https://aicost.tools/_astro/SearchModal.astro_astro_type_script_index_0_lang.C3j1IxmM.js/_astro/SearchModal.astro_astro_typ... https://aicost.tools/_astro/SearchModal.astro_astro_type_script_index_0_lang.C3j1IxmM.js — 200 — 2.5 KiB — 132 ms — h3https://agentconcierge.io/badge-icon.svgagentconcierge.io/badge-icon.svg https://agentconcierge.io/badge-icon.svg — 200 — 1.3 KiB — 169 ms — h2https://earlylaunch.co/widget/1e211b2b-5d2d-400f-898a-32c44314c7fb/script.jsearlylaunch.co/widget/1e211b2b-5d2d... https://earlylaunch.co/widget/1e211b2b-5d2d-400f-898a-32c44314c7fb/script.js — 200 — 2.4 KiB — 81 ms — h3https://aicost.tools/site.webmanifest/site.webmanifest https://aicost.tools/site.webmanifest — 200 — 792 B — 156 ms — h3https://aicost.tools/_astro/engine.B1YIArAN.js/_astro/engine.B1YIArAN.js https://aicost.tools/_astro/engine.B1YIArAN.js — 200 — 1.2 KiB — 86 ms — h3https://aicost.tools/fonts/geist-normal-latin.woff2/fonts/geist-normal-latin.woff2 https://aicost.tools/fonts/geist-normal-latin.woff2 — 200 — 29.2 KiB — 90 ms — h3https://region1.google-analytics.com/g/collect?v=2&tid=G-FN9H4RKMSJ&gtm=45je6al1h1v9253372556za208zd9253372556xf1&_p=1793022527752&gcd=13l3l3l2l1l1&npa=1&dma_cps=a&dma=1&cid=1722356645.1793022528&frm=0&ngs=1&pscdl=noapi&rcb=19&sr=800x600&uaa=x86&uab=64&uafvl=Not%253AA-Brand%3B8.0.0.0%7CChromium%3B156.0.8078.47&uam=&uamb=0&uap=macOS&uapv=10.15.7&uaw=0&ul=en-us&_s=1&tag_exp=115616985~115938465~115938468~118897920~118897930~120213116~120385423~120469145~120469153~121246026~121246034&sid=1793022528&sct=1&seg=0&dl=https%3A%2F%2Faicost.tools%2F&dt=LLM%20API%20Pricing%20%E2%80%94%20Compare%20Cost%20Across%20AI%20Models%20%C2%B7%20AI%2F%2FCOST&en=page_view&_fv=1&_nsi=1&_ss=1&_ee=1&tfd=700region1.google-analytics.com/g/coll... https://region1.google-analytics.com/g/collect?v=2&tid=G-FN9H4RKMSJ&gtm=45je6al1h1v9253372556za208zd9253372556xf1&_p=1793022527752&gcd=13l3l3l2l1l1&npa=1&dma_cps=a&dma=1&cid=1722356645.1793022528&frm=0&ngs=1&pscdl=noapi&rcb=19&sr=800x600&uaa=x86&uab=64&uafvl=Not%253AA-Brand%3B8.0.0.0%7CChromium%3B156.0.8078.47&uam=&uamb=0&uap=macOS&uapv=10.15.7&uaw=0&ul=en-us&_s=1&tag_exp=115616985~115938465~115938468~118897920~118897930~120213116~120385423~120469145~120469153~121246026~121246034&sid=1793022528&sct=1&seg=0&dl=https%3A%2F%2Faicost.tools%2F&dt=LLM%20API%20Pricing%20%E2%80%94%20Compare%20Cost%20Across%20AI%20Models%20%C2%B7%20AI%2F%2FCOST&en=page_view&_fv=1&_nsi=1&_ss=1&_ee=1&tfd=700 — 204 — 545 B — 74 ms — h2https://aicost.tools/favicon.ico/favicon.ico https://aicost.tools/favicon.ico — 200 — 2.1 KiB — 85 ms — h3https://aicost.tools/icon-192.png/icon-192.png https://aicost.tools/icon-192.png — 200 — 4.2 KiB — 59 ms — h3
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
29% of JavaScript execution is third-party
First-party Third-party 60ms · 177KB · €1/mo
Google Tag Manager
Tag Manager
Optional
Execution 60ms
Transfer 177 KB
Unused 41%
Monthly Cost €1/mo

How third-party costs are calculated

Image Optimization
144 images, 0 KB total, 0 KB wasted
INFO

Image Optimization Audit

Total Images

144

Total Size

0 KB

34 missing dimensions 2 missing lazy loading
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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