Skip to content
https://www.convertkit.com

Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
84
GRADE
B
FIX
3
REVIEW
3
PASS
8
INFO
2

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

Mobile Desktop
55
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
99
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.

2.53 s

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

8.96 s

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

572 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.

4.08 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.

9.47 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
16
8 PASS 3 REVIEW 3 FIX
D
Third-Party Impact
Action
100% third-party, 0 ms blocking
FIX
100% third-party, 0 ms blocking
Warning::
Third-party code accounts for 100% of page weight (1.7 MiB of 1.7 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
F
JS Execution Cost
Action
3939ms total JS execution
FIX
3939ms total JS execution
Warning::
https://kit.com/: 1159ms CPU time
Warning::
https://kit.com/_next/static/chunks/framework-a071...: 1022ms CPU time
Warning::
https://kit.com/_next/static/chunks/68563-5ae8d773...: 642ms CPU time
Warning::
Unattributable: 604ms CPU time
Info::
https://kit.com/_next/static/chunks/pages/index-9a...: 221ms CPU time
Warning::
Third-party scripts: 3939ms (100% of total)

Main Thread Breakdown

Script Evaluation 34% Other 33% Style & Layout 16% Rendering 11% Script Parsing & Compilation 4%
ScriptTotalScriptingParse/CompileParty
https://kit.com/1159ms23ms0ms3rd
https://kit.com/_next/static/chunks/framework-a071c7e3156668e1.js1022ms718ms21ms3rd
https://kit.com/_next/static/chunks/68563-5ae8d773d8aebd21.js642ms99ms16ms3rd
Unattributable604ms26ms0ms3rd
https://kit.com/_next/static/chunks/pages/index-9a22a715266f8c88.js221ms219ms1ms3rd
https://kit.com/_next/static/chunks/webpack-b4f49bdf80a6e621.js117ms102ms3ms3rd
https://kit.com/_next/static/chunks/pages/_app-67844995a9b7e744.js91ms76ms14ms3rd
https://kit.com/_next/static/chunks/main-ff96fca99dd86bec.js84ms71ms12ms3rd
F
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

C
Page Weight Budget
Action
1.7 MB transferred, 112 requests
REVIEW
1.7 MB transferred, 112 requests
Info::
Page weighs 3.0 MB (1.7 MB transferred)
Warning::
Images are 1.1 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 1.1 MB
Warning::
112 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 0.36 g CO2 per page load
1.7 MB / 2.4 MB budget
1.7 MB transferred
112 requests
0.36 g CO2 per page load
Images 1.1 MiB 65%
JavaScript 439.8 KiB 25%
Fonts 96.5 KiB 6%
HTML 49.6 KiB 3%
CSS 25.6 KiB 1%
Other 3.1 KiB 0%
Other 1009 B 0%
Other 978 B 0%
Other 166 B 0%
0 2.4 MB 4.9 MB
Approaching limit

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

Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.

Why this matters

High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.

Source: web.dev

B
JS Bundles
60 scripts, 64 KB unused
REVIEW
60 scripts, 64 KB unused
Warning::
https://kit.com/_next/static/chunks/framework-a071...: 22 KB unused (37%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://kit.com/_next/static/chunks/68563-5ae8d773...: 22 KB unused (53%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://kit.com/_next/static/chunks/pages/_app-678...: 20 KB unused (44%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 64 KB
64 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://kit.com/_next/static/chunks/framework-a071c7e3156668e1.js60 KB22 KB (37%)✓3rd
https://kit.com/_next/static/chunks/68563-5ae8d773d8aebd21.js42 KB22 KB (53%)✓3rd
https://kit.com/_next/static/chunks/pages/_app-67844995a9b7e744.js46 KB20 KB (44%)✓3rd
https://kit.com/_next/static/chunks/83964.e52dd721083aaf06.js2 KB—✓3rd
https://kit.com/_next/static/chunks/39392.ed202e1761a6f17e.js9 KB—✓3rd
https://kit.com/_next/static/chunks/25708.0c148a6db1c836c3.js1 KB—✓3rd
https://kit.com/_next/static/chunks/86638.914eb303cd768327.js1 KB—✓3rd
https://kit.com/_next/static/chunks/90300.6a725e5caf348700.js1 KB—✓3rd
https://kit.com/_next/static/chunks/63128.ea309b49502e877f.js3 KB—✓3rd
https://kit.com/_next/static/chunks/37794.57ff31e17f884de2.js1 KB—✓3rd

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

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

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

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
37 images, 0 KB saveable
PASS
37 images, 0 KB saveable
Info::
All images are well-optimized
37 images 1.1 MB
0 oversized -0 KB
0 legacy format
0 missing dimensions CLS risk
A+
Font Loading
3 fonts (97 KB)
PASS
3 fonts (97 KB)
Info::
3 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

3

97 KB total

Render-blocking

0

of 3

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s 6.0 s 7.0 s 8.0 s 9.0 s FCP 2.5 s LCP 9.0 shttps://kit.com/_next/static/media/2a7abadac7ce6faa-s.p.woff22a7abadac7ce6faa-s.p.woff2 https://kit.com/_next/static/media/2a7abadac7ce6faa-s.p.woff2 — 32.4 KiB — 0 ms — font-display: swaphttps://kit.com/_next/static/media/92daa4d0098aa288-s.p.woff292daa4d0098aa288-s.p.woff2 https://kit.com/_next/static/media/92daa4d0098aa288-s.p.woff2 — 28.9 KiB — 0 ms — font-display: swaphttps://kit.com/_next/static/media/bf61ec490084b651-s.p.woff2bf61ec490084b651-s.p.woff2 https://kit.com/_next/static/media/bf61ec490084b651-s.p.woff2 — 35.2 KiB — 0 ms — font-display: swap
2a7abadac7ce6faa-s.p.woff2 woff2 swap
Size 32 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
92daa4d0098aa288-s.p.woff2 woff2 swap
Size 29 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
bf61ec490084b651-s.p.woff2 woff2 swap
Size 35 KB
Load time 0 ms
Start 0 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
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+
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
Network Waterfall
112 requests over 0ms
INFO

Performance analysis not available for this result.

Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
100% of JavaScript execution is third-party
First-party Third-party 3939ms · 250KB · $52/mo
kit.com
Other
Costly
Execution 1159ms
Transfer 50 KB
Monthly Cost $15/mo
kit.com
Other
Costly
Execution 1022ms
Transfer 60 KB
Unused 37%
Monthly Cost $14/mo
kit.com
Other
Costly
Execution 642ms
Transfer 42 KB
Unused 53%
Monthly Cost $9/mo
Unattributable
Other
Costly
Execution 604ms
Transfer 0 KB
Monthly Cost $8/mo
kit.com
Other
Costly
Execution 221ms
Transfer 5 KB
Monthly Cost $3/mo
kit.com
Other
Optional
Execution 117ms
Transfer 12 KB
Monthly Cost $2/mo
kit.com
Other
Optional
Execution 91ms
Transfer 46 KB
Unused 44%
Monthly Cost $1/mo
kit.com
Other
Optional
Execution 84ms
Transfer 37 KB
Monthly Cost $1/mo

These scripts may cost more than they're worth

  • kit.com adds 1159ms and costs ~$15/month
  • kit.com adds 1022ms and costs ~$14/month
  • kit.com adds 642ms and costs ~$9/month
  • Unattributable adds 604ms and costs ~$8/month
  • kit.com adds 221ms and costs ~$3/month

100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.

Why this matters

When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.

Learn more ▾

Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.

Source: web.dev

kit.com takes 1159ms 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

kit.com takes 1022ms 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

kit.com takes 642ms 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

53% of kit.com's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

Source: web.dev

Unattributable takes 604ms 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

kit.com takes 221ms 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.

Send Feedback