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https://www.clickhouse.com

Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
72
GRADE
C
FIX
5
REVIEW
1
PASS
8
INFO
2

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

Mobile Desktop
39
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
92
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
92
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.

2.66 s

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

16.47 s

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

1.31 s

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.005

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

7.49 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.

24.80 s

Page Load Progression

454 ms
907 ms
1.4 s
1.8 s
2.3 s
2.7 s
3.2 s
3.6 s
Checks
16
8 PASS 1 REVIEW 5 FIX
F
Page Weight Budget
Action
4.1 MB transferred, 173 requests
FIX
4.1 MB transferred, 173 requests
Critical::
Page weighs 19.3 MB (4.1 MB transferred)
Warning::
JavaScript is 2.4 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 2.4 MB
Warning::
173 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 0.85 g CO2 per page load
4.1 MB / 2.4 MB budget
4.1 MB transferred
173 requests
0.85 g CO2 per page load
JavaScript 2.4 MiB 59%
Images 599.0 KiB 14%
Other 410.3 KiB 10%
HTML 209.1 KiB 5%
Fonts 193.5 KiB 5%
CSS 153.9 KiB 4%
Other 127.6 KiB 3%
Other 20.1 KiB 0%
Other 4.5 KiB 0%
Other 482 B 0%
Other 164 B 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Over budget

Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.

Why this matters

JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.

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

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 (4.1 MiB of 4.1 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
F
JS Execution Cost
Action
8749ms total JS execution
FIX
8749ms total JS execution
Warning::
https://clickhouse.com/: 3225ms CPU time
Warning::
https://clickhouse.com/_next/static/chunks/framewo...: 1217ms CPU time
Warning::
Unattributable: 1192ms CPU time
Warning::
https://clickhouse.com/_next/static/chunks/3012-7c...: 513ms CPU time
Warning::
https://clickhouse.com/_next/static/chunks/pages/_...: 448ms CPU time
Warning::
Third-party scripts: 8749ms (100% of total)

Main Thread Breakdown

Script Evaluation 33% Other 32% Style & Layout 20% Rendering 8% Script Parsing & Compilation 7%
ScriptTotalScriptingParse/CompileParty
https://clickhouse.com/3225ms26ms1ms3rd
https://clickhouse.com/_next/static/chunks/framework-7b9e6922c3bd411b.js1217ms740ms63ms3rd
Unattributable1192ms87ms0ms3rd
https://clickhouse.com/_next/static/chunks/3012-7ca6a1b5ca3849ba.js513ms158ms9ms3rd
https://clickhouse.com/_next/static/chunks/pages/_app-a4eafd4565895685.js448ms294ms137ms3rd
https://clickhouse.com/_next/static/chunks/main-640004828a30dcfe.js402ms363ms10ms3rd
https://clickhouse.com/gtmwksrxs8s/?id=G-KF1LLRTQ5Q&cx=c&gtm=4e6460400ms250ms46ms3rd
https://clickhouse.com/gtmwksrxs8s/?id=GTM-WKSRXS8S316ms245ms59ms3rd
https://clickhouse.com/_next/static/chunks/pages/index-328dbbf6dc8f0762.js230ms210ms20ms3rd
https://clickhouse.com/_next/static/chunks/5440-6e13b0ad92d9502b.js151ms3ms8ms3rd

Showing top 10 of 17 scripts

F
JS Bundles
Action
59 scripts, 1.1 MB unused
FIX
59 scripts, 1.1 MB unused
Warning::
https://clickhouse.com/_next/static/chunks/pages/_...: 297 KB unused (75%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://clickhouse.com/_next/static/chunks/937-b0e...: 141 KB unused (78%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://clickhouse.com/_next/static/chunks/937-b0e...: 141 KB unused (78%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://clickhouse.com/_next/static/chunks/7799-f0...: 136 KB unused (54%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://cdn-prod.securiti.ai/consent/cookie-consen...: 84 KB unused (76%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 1.1 MB
1148 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://clickhouse.com/_next/static/chunks/pages/_app-a4eafd4565895685.js397 KB297 KB (75%)✓3rd
https://clickhouse.com/_next/static/chunks/937-b0e6597368c6d53f.js0 KB141 KB (78%)✓3rd
https://clickhouse.com/_next/static/chunks/937-b0e6597368c6d53f.js52 KB141 KB (78%)✓3rd
https://clickhouse.com/_next/static/chunks/7799-f0a67ac3c7525c39.js257 KB136 KB (54%)✓3rd
https://cdn-prod.securiti.ai/consent/cookie-consent-sdk-strict-csp-latest.js112 KB84 KB (76%)✓3rd
https://clickhouse.com/gtmwksrxs8s/?id=GTM-WKSRXS8S168 KB73 KB (43%)✓3rd
https://clickhouse.com/_next/static/chunks/fec483df-91a51f18f1588b11.js103 KB70 KB (71%)✓3rd
https://clickhouse.com/_next/static/chunks/pages/index-328dbbf6dc8f0762.js96 KB65 KB (71%)✓3rd
https://clickhouse.com/gtmwksrxs8s/?id=G-KF1LLRTQ5Q&cx=c&gtm=4e6460184 KB65 KB (35%)✓3rd
https://clickhouse.com/_next/static/chunks/framework-7b9e6922c3bd411b.js69 KB30 KB (46%)✓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

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

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.

B
Image Optimization
51 images, 0 KB saveable
REVIEW
51 images, 0 KB saveable
Info::
All images are well-optimized
51 images 599 KB
0 oversized -0 KB
47 legacy format
0 missing dimensions CLS risk
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+
Font Loading
8 fonts (194 KB)
PASS
8 fonts (194 KB)
Info::
8 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

8

194 KB total

Render-blocking

0

of 8

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 2.0 s 4.0 s 6.0 s 8.0 s 10.0 s 12.0 s 14.0 s 16.0 s FCP 2.7 s LCP 16.5 shttps://clickhouse.com/_next/static/media/27388ed889759f5f-s.p.woff27388ed889759f5f-s.p.woff https://clickhouse.com/_next/static/media/27388ed889759f5f-s.p.woff — 25.5 KiB — 0 ms — font-display: swaphttps://clickhouse.com/_next/static/media/6e8200c122e80191-s.p.woff6e8200c122e80191-s.p.woff https://clickhouse.com/_next/static/media/6e8200c122e80191-s.p.woff — 25.4 KiB — 0 ms — font-display: swaphttps://clickhouse.com/_next/static/media/f500045cc492a7fa-s.p.wofff500045cc492a7fa-s.p.woff https://clickhouse.com/_next/static/media/f500045cc492a7fa-s.p.woff — 25.0 KiB — 0 ms — font-display: swaphttps://clickhouse.com/_next/static/media/e4af272ccee01ff0.woff2e4af272ccee01ff0.woff2 https://clickhouse.com/_next/static/media/e4af272ccee01ff0.woff2 — 51.4 KiB — 0 ms — font-display: swaphttps://clickhouse.com/_next/static/media/d8c14dc5fcaf3a63.woff2d8c14dc5fcaf3a63.woff2 https://clickhouse.com/_next/static/media/d8c14dc5fcaf3a63.woff2 — 32.4 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2KFO7CnqEu92Fr1ME7kSn66a... https://fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2 — 33.9 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2KFO7CnqEu92Fr1ME7kSn66a... https://fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2 — 0 B — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2KFO7CnqEu92Fr1ME7kSn66a... https://fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2 — 0 B — 0 ms — font-display: swap
27388ed889759f5f-s.p.woff woff swap
Size 26 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
6e8200c122e80191-s.p.woff woff swap
Size 25 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
f500045cc492a7fa-s.p.woff woff swap
Size 25 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
e4af272ccee01ff0.woff2 woff2 swap
Size 51 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
d8c14dc5fcaf3a63.woff2 woff2 swap
Size 32 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
KFO7CnqEu92Fr1ME7kSn66a... woff2 swap
Size 34 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
KFO7CnqEu92Fr1ME7kSn66a... woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
KFO7CnqEu92Fr1ME7kSn66a... woff2 swap
Size 0 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)

Fixing the unchecked items could save ~23 KB and ~46 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
6 hints, 0 missing preconnects
PASS
6 hints, 0 missing preconnects
Info::
Page uses 6 resource hint(s)

Current Resource Hints

preconnect
—
preload
6
dns-prefetch
—
prefetch
—

6 resource hints configured

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+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Cloudflare

Network Waterfall
173 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 8749ms · 1529KB · €95/mo
clickhouse.com
Other
Costly
Execution 3225ms
Transfer 49 KB
Monthly Cost €35/mo
clickhouse.com
Other
Costly
Execution 1217ms
Transfer 69 KB
Unused 46%
Monthly Cost €13/mo
Unattributable
Other
Costly
Execution 1192ms
Transfer 0 KB
Monthly Cost €13/mo
clickhouse.com
Other
Costly
Execution 513ms
Transfer 34 KB
Monthly Cost €6/mo
clickhouse.com
Other
Costly
Execution 448ms
Transfer 397 KB
Unused 75%
Monthly Cost €5/mo
clickhouse.com
Other
Costly
Execution 402ms
Transfer 42 KB
Monthly Cost €4/mo
clickhouse.com
Other
Costly
Execution 400ms
Transfer 184 KB
Unused 35%
Monthly Cost €4/mo
clickhouse.com
Other
Costly
Execution 316ms
Transfer 168 KB
Unused 43%
Monthly Cost €3/mo
clickhouse.com
Other
Costly
Execution 230ms
Transfer 96 KB
Unused 71%
Monthly Cost €2/mo
clickhouse.com
Other
Optional
Execution 151ms
Transfer 24 KB
Monthly Cost €2/mo
cdn-prod.securiti.ai
Other
Optional
Execution 142ms
Transfer 6 KB
Monthly Cost €2/mo
www.youtube.com
Other
Optional
Execution 126ms
Transfer 11 KB
Monthly Cost €1/mo
x.clearbitjs.com
Other
Optional
Execution 96ms
Transfer 45 KB
Monthly Cost €1/mo
clickhouse.com
Other
Optional
Execution 95ms
Transfer 257 KB
Unused 54%
Monthly Cost €1/mo
cdn-prod.securiti.ai
Other
Optional
Execution 91ms
Transfer 112 KB
Unused 76%
Monthly Cost €1/mo
clickhouse.com
Other
Optional
Execution 52ms
Transfer 6 KB
Monthly Cost €1/mo
tag.unifyintent.com
Other
Optional
Execution 51ms
Transfer 30 KB
Monthly Cost €1/mo

These scripts may cost more than they're worth

  • clickhouse.com adds 3225ms and costs ~€35/month
  • clickhouse.com adds 1217ms and costs ~€13/month
  • Unattributable adds 1192ms and costs ~€13/month
  • clickhouse.com adds 513ms and costs ~€6/month
  • clickhouse.com adds 448ms and costs ~€5/month
  • clickhouse.com adds 402ms and costs ~€4/month
  • clickhouse.com adds 400ms and costs ~€4/month
  • clickhouse.com adds 316ms and costs ~€3/month
  • clickhouse.com adds 230ms and costs ~€2/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

clickhouse.com takes 3225ms 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

clickhouse.com takes 1217ms 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

Unattributable takes 1192ms 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

clickhouse.com takes 513ms 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

clickhouse.com takes 448ms 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

75% of clickhouse.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

clickhouse.com takes 402ms 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

clickhouse.com takes 400ms 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

clickhouse.com takes 316ms 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

clickhouse.com takes 230ms 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

71% of clickhouse.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

54% of clickhouse.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

76% of cdn-prod.securiti.ai'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

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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