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https://nmap.org

Performance

· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
90
GRADE
A
FIX
2
REVIEW
2
PASS
9
INFO
2

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.
90
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.
92
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.

803 ms

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

803 ms

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

1 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.

803 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.

1.21 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
15
9 PASS 2 REVIEW 2 FIX
D
Third-Party Impact
Action
76% third-party, 0 ms blocking
FIX
76% third-party, 0 ms blocking
Warning::
Third-party code accounts for 76% of page weight (169.7 KiB of 223.4 KiB)
Info::
Third-party blocking time is low (0 ms)
24%
76%
First-party Third-party
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
JS Bundles
3 scripts, 64 KB unused
REVIEW
3 scripts, 64 KB unused
Warning::
https://www.googletagmanager.com/gtag/js?id=G-ZLCV...: 64 KB unused (43%)
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://www.googletagmanager.com/gtag/js?id=G-ZLCVHN7NXS&cx=c&_slc=1148 KB64 KB (43%)✓3rd
https://www.google-analytics.com/analytics.js21 KB—✓3rd
https://nmap.org/shared/js/nst.js?v=23 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

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

Green Hosting

No green hosting detected

A+
Page Weight Budget
223 KB transferred, 12 requests
PASS
223 KB transferred, 12 requests
Info::
Page weighs 523 KB (223 KB transferred)
Info::
12 HTTP requests
Info::
Estimated 0.05 g CO2 per page load
223 KB / 2.4 MB budget
223 KB transferred
12 requests
0.05 g CO2 per page load
JavaScript 171.8 KiB 77%
Images 23.6 KiB 11%
HTML 19.6 KiB 9%
CSS 7.1 KiB 3%
Other 919 B 0%
Other 460 B 0%
Other 20 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
2 images, 0 KB saveable
PASS
2 images, 0 KB saveable
Info::
All images are well-optimized
2 images 24 KB
0 oversized -0 KB
2 legacy format
0 missing dimensions CLS risk
A+
JS Execution Cost
55ms total JS execution
PASS
55ms total JS execution
Info::
https://www.googletagmanager.com/gtag/js?id=G-ZLCV...: 55ms CPU time
Warning::
Third-party scripts: 55ms (100% of total)

Main Thread Breakdown

Script Evaluation 43% Other 22% Style & Layout 17% Script Parsing & Compilation 9% Rendering 5%
ScriptTotalScriptingParse/CompileParty
https://www.googletagmanager.com/gtag/js?id=G-ZLCVHN7NXS&cx=c&_slc=155ms41ms14ms3rd
A+
Font Loading
No web fonts (system fonts)
PASS
No web fonts (system fonts)
Info::
No web fonts loaded — system fonts are fastest
No web fonts loaded — system fonts are optimal.
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
Page Weight Inventory
12 resources · 223 KB · 64 KB savings available
PASS
12 resources · 223 KB · 64 KB savings available
Info::
Within 1MB page-weight target
Got: 223 KB
Info::
~64 KB of savings available
Warning::
4 third-party resources (76% of weight)
12 resources · 223.4 KiB · 4 third-party Within 1MB page-weight target
JavaScript 77% · 171.8 KiB
Image 11% · 24.5 KiB
Document 9% · 19.6 KiB
CSS 3% · 7.1 KiB
Other 0% · 480 B

~64.4 KiB of savings available

Remove unused JavaScript: 64.4 KiB
Network Waterfall
12 requests over 736ms
INFO
0 ms 200 ms 400 ms 600 ms 800 ms FCP 803 ms LCP 803 mshttps://nmap.org// https://nmap.org/ — 200 — 19.6 KiB — 330 ms — http/1.1https://nmap.org/images/sitelogo.png/images/sitelogo.png https://nmap.org/images/sitelogo.png — 200 — 18.5 KiB — 133 ms — http/1.1https://nmap.org/shared/images/nst-icons.svg/shared/images/nst-icons.svg https://nmap.org/shared/images/nst-icons.svg — 200 — 5.1 KiB — 199 ms — http/1.1https://nmap.org/shared/css/nst.css?v=2/shared/css/nst.css?v=2 https://nmap.org/shared/css/nst.css?v=2 — 200 — 4.9 KiB — 118 ms — http/1.1https://nmap.org/site.css/site.css https://nmap.org/site.css — 200 — 1.2 KiB — 184 ms — http/1.1https://www.google-analytics.com/analytics.jswww.google-analytics.com/analytics.... https://www.google-analytics.com/analytics.js — 200 — 20.9 KiB — 27 ms — h2https://nmap.org/shared/js/nst.js?v=2/shared/js/nst.js?v=2 https://nmap.org/shared/js/nst.js?v=2 — 200 — 2.6 KiB — 66 ms — http/1.1https://www.google-analytics.com/j/collect?v=1&_v=j102&a=1167804932&t=pageview&_s=1&dl=https%3A%2F%2Fnmap.org%2F&ul=en-us&dt=Nmap%3A%20the%20Network%20Mapper%20-%20Free%20Security%20Scanner&sr=800x600&vp=1350x940&_u=IEBAAEABAAAAACAAI~&jid=475617033&gjid=958004164&cid=1377493272.1776897114&tid=UA-11009417-1&_gid=363353968.1776897114&_r=1&_slc=1&z=1244368497www.google-analytics.com/j/collect?... https://www.google-analytics.com/j/collect?v=1&_v=j102&a=1167804932&t=pageview&_s=1&dl=https%3A%2F%2Fnmap.org%2F&ul=en-us&dt=Nmap%3A%20the%20Network%20Mapper%20-%20Free%20Security%20Scanner&sr=800x600&vp=1350x940&_u=IEBAAEABAAAAACAAI~&jid=475617033&gjid=958004164&cid=1377493272.1776897114&tid=UA-11009417-1&_gid=363353968.1776897114&_r=1&_slc=1&z=1244368497 — 200 — 460 B — 77 ms — h2https://nmap.org/shared/css/nst-foot.css?v=2/shared/css/nst-foot.css?v=2 https://nmap.org/shared/css/nst-foot.css?v=2 — 200 — 968 B — 67 ms — http/1.1https://www.googletagmanager.com/gtag/js?id=G-ZLCVHN7NXS&cx=c&_slc=1www.googletagmanager.com/gtag/js?id... https://www.googletagmanager.com/gtag/js?id=G-ZLCVHN7NXS&cx=c&_slc=1 — 200 — 148.3 KiB — 71 ms — h2https://nmap.org/shared/images/tiny-eyeicon.png/shared/images/tiny-eyeicon.png https://nmap.org/shared/images/tiny-eyeicon.png — 200 — 919 B — 67 ms — http/1.1https://www.google-analytics.com/g/collect?v=2&tid=G-ZLCVHN7NXS&gtm=45je64k0v9134945724za20g&_p=1776897114480&gcd=13l3l3l3l2l1&npa=0&dma=0&_eu=ABAI&are=1&cid=1377493272.1776897114&frm=0&pscdl=noapi&rcb=1&sr=800x600&uaa=x86&uab=64&uafvl=Not-A.Brand%3B24.0.0.0%7CChromium%3B146.0.7680.164&uam=&uamb=0&uap=macOS&uapv=10.15.7&uaw=0&ul=en-us&_s=1&tag_exp=0~115616986~115938466~115938469~117266401~117512542&dl=https%3A%2F%2Fnmap.org%2F&dt=Nmap%3A%20the%20Network%20Mapper%20-%20Free%20Security%20Scanner&sid=1776897114&sct=1&seg=0&_tu=wAQ&en=page_view&_fv=1&_ss=1&_ee=1&tfd=716www.google-analytics.com/g/collect?... https://www.google-analytics.com/g/collect?v=2&tid=G-ZLCVHN7NXS&gtm=45je64k0v9134945724za20g&_p=1776897114480&gcd=13l3l3l3l2l1&npa=0&dma=0&_eu=ABAI&are=1&cid=1377493272.1776897114&frm=0&pscdl=noapi&rcb=1&sr=800x600&uaa=x86&uab=64&uafvl=Not-A.Brand%3B24.0.0.0%7CChromium%3B146.0.7680.164&uam=&uamb=0&uap=macOS&uapv=10.15.7&uaw=0&ul=en-us&_s=1&tag_exp=0~115616986~115938466~115938469~117266401~117512542&dl=https%3A%2F%2Fnmap.org%2F&dt=Nmap%3A%20the%20Network%20Mapper%20-%20Free%20Security%20Scanner&sid=1776897114&sct=1&seg=0&_tu=wAQ&en=page_view&_fv=1&_ss=1&_ee=1&tfd=716 — 204 — 20 B — 19 ms — h3
HTML JavaScript CSS Images Fonts XHR/Fetch Other
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 55ms · 148KB · €1/mo
Google Tag Manager
Tag Manager
Optional
Execution 55ms
Transfer 148 KB
Unused 43%
Monthly Cost €1/mo

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

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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