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https://puretechleman.ch

Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
89
GRADE
B
FIX
1
REVIEW
4
PASS
10
INFO
2

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

Mobile Desktop
67
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
97
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.

3.12 s

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

5.25 s

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

216 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.

5.35 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.

5.26 s

Page Load Progression

582 ms
1.2 s
1.7 s
2.3 s
2.9 s
3.5 s
4.1 s
4.7 s
Checks
17
10 PASS 4 REVIEW 1 FIX
D
JS Execution Cost
Action
2102ms total JS execution
FIX
2102ms total JS execution
Warning::
https://puretechleman.ch/: 1017ms CPU time
Warning::
https://www.googletagmanager.com/gtag/js?id=G-0TSC...: 533ms CPU time
Warning::
https://puretechleman.ch/assets/main-CFQN0IbE.js: 346ms CPU time
Info::
Unattributable: 151ms CPU time
Info::
https://puretechleman.ch/~flock.js: 54ms CPU time
Info::
Third-party scripts: 684ms (33% of total)

Main Thread Breakdown

Other 32% Style & Layout 30% Script Evaluation 23% Rendering 11%
ScriptTotalScriptingParse/CompileParty
https://puretechleman.ch/1017ms6ms2ms1st
https://www.googletagmanager.com/gtag/js?id=G-0TSC8HDBTF533ms219ms38ms3rd
https://puretechleman.ch/assets/main-CFQN0IbE.js346ms212ms2ms1st
Unattributable151ms7ms0ms3rd
https://puretechleman.ch/~flock.js54ms39ms2ms1st
B
Third-Party Impact
53% third-party, 0 ms blocking
REVIEW
53% third-party, 0 ms blocking
Warning::
Third-party code accounts for 53% of page weight (213.9 KiB of 401.4 KiB)
Info::
Third-party blocking time is low (0 ms)
47%
53%
First-party Third-party
B
JS Bundles
3 scripts, 123 KB unused
REVIEW
3 scripts, 123 KB unused
Warning::
https://www.googletagmanager.com/gtag/js?id=G-0TSC...: 65 KB unused (42%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://puretechleman.ch/assets/main-CFQN0IbE.js: 57 KB unused (40%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 123 KB
123 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.googletagmanager.com/gtag/js?id=G-0TSC8HDBTF157 KB65 KB (42%)✓3rd
https://puretechleman.ch/assets/main-CFQN0IbE.js145 KB57 KB (40%)✓1st
https://puretechleman.ch/~flock.js8 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

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

B
HTTP Caching
no-cache, must-revalidate, max-age=0
REVIEW
no-cache, must-revalidate, max-age=0
Info::
Cache-Control header is set
Got: no-cache, must-revalidate, max-age=0
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

no-cache, must-revalidate, max-age=0

DirectiveValueMeaning
no-cache—Cache but always revalidate first
must-revalidate—Must recheck with server after expiry
max-age0Cache for 0 seconds
A+
Page Weight Budget
401 KB transferred, 12 requests
PASS
401 KB transferred, 12 requests
Info::
Page weighs 1.2 MB (401 KB transferred)
Info::
12 HTTP requests
Info::
Estimated 0.08 g CO2 per page load
401 KB / 2.4 MB budget
401 KB transferred
12 requests
0.08 g CO2 per page load
JavaScript 310.5 KiB 77%
Fonts 54.7 KiB 14%
CSS 18.8 KiB 5%
HTML 15.9 KiB 4%
Images 584 B 0%
Other 549 B 0%
Other 306 B 0%
Other 102 B 0%
0 2.4 MB 4.9 MB
Under budget
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
1 images, 0 KB saveable
PASS
1 images, 0 KB saveable
Warning::
https://puretechleman.ch/ptl-mark-white.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
1 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

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

A+
Font Loading
2 fonts (55 KB)
PASS
2 fonts (55 KB)
Info::
2 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

2

55 KB total

Render-blocking

0

of 2

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 FCP 3.1 s LCP 5.2 shttps://fonts.gstatic.com/s/jetbrainsmono/v24/tDbv2o-flEEny0FZhsfKu5WU4zr3E_BX0PnT8RD8yKwBNntkaToggR7BYRbKPxDcwgknk-4.woff2tDbv2o-flEEny0FZhsfKu5W... https://fonts.gstatic.com/s/jetbrainsmono/v24/tDbv2o-flEEny0FZhsfKu5WU4zr3E_BX0PnT8RD8yKwBNntkaToggR7BYRbKPxDcwgknk-4.woff2 — 30.6 KiB — 31 ms — font-display: swaphttps://fonts.gstatic.com/s/manrope/v20/xn7gYHE41ni1AdIRggexSvfedN4.woff2xn7gYHE41ni1AdIRggexSvf... https://fonts.gstatic.com/s/manrope/v20/xn7gYHE41ni1AdIRggexSvfedN4.woff2 — 24.0 KiB — 33 ms — font-display: swap
tDbv2o-flEEny0FZhsfKu5W... woff2 swap
Size 31 KB
Load time 31 ms
Start 454 ms
Risk FOUT — text flashes from fallback to web font
xn7gYHE41ni1AdIRggexSvf... woff2 swap
Size 24 KB
Load time 33 ms
Start 456 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
5 hints, 0 missing preconnects
PASS
5 hints, 0 missing preconnects
Info::
Page uses 5 resource hint(s)

Current Resource Hints

preconnect
2
preload
3
dns-prefetch
—
prefetch
—

5 resource hints configured

A
Page Weight Inventory
12 resources · 401 KB · 123 KB savings available
PASS
12 resources · 401 KB · 123 KB savings available
Info::
Within 1MB page-weight target
Got: 401 KB
Info::
~123 KB of savings available
Warning::
5 third-party resources (53% of weight)
12 resources · 401.4 KiB · 5 third-party Within 1MB page-weight target
JavaScript 77% · 310.5 KiB
Font 14% · 54.7 KiB
CSS 5% · 18.8 KiB
Document 4% · 15.9 KiB
Image 0% · 890 B
Other 0% · 651 B

~122.6 KiB of savings available

Remove unused JavaScript: 122.6 KiB
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
12 requests over 1629ms
INFO
0 ms 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s FCP 3.1 s LCP 5.2 shttps://puretechleman.ch// https://puretechleman.ch/ — 200 — 15.9 KiB — 165 ms — h2https://puretechleman.ch/ptl-mark-white.svg/ptl-mark-white.svg https://puretechleman.ch/ptl-mark-white.svg — 200 — 584 B — 124 ms — h2https://www.googletagmanager.com/gtag/js?id=G-0TSC8HDBTFwww.googletagmanager.com/gtag/js?id... https://www.googletagmanager.com/gtag/js?id=G-0TSC8HDBTF — 200 — 157.3 KiB — 152 ms — h2https://puretechleman.ch/assets/main-CFQN0IbE.js/assets/main-CFQN0IbE.js https://puretechleman.ch/assets/main-CFQN0IbE.js — 200 — 145.1 KiB — 196 ms — h2https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@400;500;700&family=Manrope:wght@300;400;500;600;700;800&display=swapfonts.googleapis.com/css2?family=Je... https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@400;500;700&family=Manrope:wght@300;400;500;600;700;800&display=swap — 200 — 1.4 KiB — 95 ms — h2https://puretechleman.ch/assets/styles-COf--v6T.css/assets/styles-COf--v6T.css https://puretechleman.ch/assets/styles-COf--v6T.css — 200 — 17.3 KiB — 130 ms — h2https://puretechleman.ch/~flock.js/~flock.js https://puretechleman.ch/~flock.js — 200 — 8.2 KiB — 112 ms — h2https://fonts.gstatic.com/s/jetbrainsmono/v24/tDbv2o-flEEny0FZhsfKu5WU4zr3E_BX0PnT8RD8yKwBNntkaToggR7BYRbKPxDcwgknk-4.woff2fonts.gstatic.com/s/jetbrainsmono/v... https://fonts.gstatic.com/s/jetbrainsmono/v24/tDbv2o-flEEny0FZhsfKu5WU4zr3E_BX0PnT8RD8yKwBNntkaToggR7BYRbKPxDcwgknk-4.woff2 — 200 — 30.6 KiB — 31 ms — h3https://fonts.gstatic.com/s/manrope/v20/xn7gYHE41ni1AdIRggexSvfedN4.woff2fonts.gstatic.com/s/manrope/v20/xn7... https://fonts.gstatic.com/s/manrope/v20/xn7gYHE41ni1AdIRggexSvfedN4.woff2 — 200 — 24.0 KiB — 33 ms — h3https://puretechleman.ch/favicon.svg/favicon.svg https://puretechleman.ch/favicon.svg — 200 — 306 B — 148 ms — h2https://puretechleman.ch/~api/analytics/~api/analytics https://puretechleman.ch/~api/analytics — 200 — 102 B — 863 ms — h2https://region1.google-analytics.com/g/collect?v=2&tid=G-0TSC8HDBTF&gtm=45je6511v9251214526za200zd9251214526&_p=1777992774182&gcs=G100&gcd=13p3p3p2p5l1&npa=1&dma_cps=-&dma=1&are=1&cid=2020941361.1777992775&frm=0&pscdl=denied&rcb=13&sr=412x823&uaa=&uab=64&uafvl=Chromium%3B147.0.7727.137%7CNot.A%252FBrand%3B8.0.0.0&uam=moto%20g%20power%20(2022)&uamb=1&uap=Android&uapv=11.0&uaw=0&ul=en-us&_s=1&tag_exp=0~115938466~115938468&sid=1777992774&sct=1&seg=0&dl=https%3A%2F%2Fpuretechleman.ch%2F&dt=Pure%20Tech%20Leman%20%E2%80%94%20Digital%20Studio%20Geneva%20%7C%20Web%2C%20Automation%2C%20Strategy&en=page_view&_fv=1&_nsi=1&_ss=1&_ee=1&tfd=881region1.google-analytics.com/g/coll... https://region1.google-analytics.com/g/collect?v=2&tid=G-0TSC8HDBTF&gtm=45je6511v9251214526za200zd9251214526&_p=1777992774182&gcs=G100&gcd=13p3p3p2p5l1&npa=1&dma_cps=-&dma=1&are=1&cid=2020941361.1777992775&frm=0&pscdl=denied&rcb=13&sr=412x823&uaa=&uab=64&uafvl=Chromium%3B147.0.7727.137%7CNot.A%252FBrand%3B8.0.0.0&uam=moto%20g%20power%20(2022)&uamb=1&uap=Android&uapv=11.0&uaw=0&ul=en-us&_s=1&tag_exp=0~115938466~115938468&sid=1777992774&sct=1&seg=0&dl=https%3A%2F%2Fpuretechleman.ch%2F&dt=Pure%20Tech%20Leman%20%E2%80%94%20Digital%20Studio%20Geneva%20%7C%20Web%2C%20Automation%2C%20Strategy&en=page_view&_fv=1&_nsi=1&_ss=1&_ee=1&tfd=881 — 204 — 549 B — 89 ms — h2
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
33% of JavaScript execution is third-party
First-party Third-party 684ms · 157KB · CHF3/mo
Google Tag Manager
Tag Manager
Costly
Execution 533ms
Transfer 157 KB
Unused 42%
Monthly Cost CHF3/mo
Unattributable
Other
Optional
Execution 151ms
Transfer 0 KB
Monthly Cost CHF1/mo

These scripts may cost more than they're worth

  • Google Tag Manager adds 533ms and costs ~CHF3/month

Google Tag Manager takes 533ms 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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