🌐 w3c.io 200 🔒 SSL Valid
Checked: just now 🔗 Visit site
HTTP Status ?A three-digit code showing if the site loaded successfully (200), redirects (301/302), or has errors (4xx/5xx).Read more →
200
SSL Expires ?When the SSL certificate expires. An expired certificate causes browser security warnings.Read more →
in 82d
Domain Expires ?When the domain registration expires. If not renewed, the domain becomes available to others.Read more →
N/A
Hosting ?The company and location where this website's server is physically located.Read more →
Unknown
Security ?Score based on key HTTP security headers: HSTS, Content-Security-Policy, and X-Frame-Options.Read more →
2/3
IP Address ?The numerical address of the server hosting this website. Reveals location, provider, and network.Read more →
104.21.47.180
Performance ?Lighthouse performance score from Google PageSpeed Insights (0–100). Measures real-world loading speed, interactivity and visual stability.
N/A
Uptime
N/A
⚡ Performance ?Lighthouse performance score from Google PageSpeed Insights (0–100). Measures real-world loading speed, interactivity and visual stability.
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Performance data not available yet.

🛠️ Tech Stack ?Technologies detected on this website: CMS, frameworks, libraries, CDN, and analytics tools. 1
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🌐 CDN
Cloudflare
📸 Screenshot Processing...
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⏳

Screenshot is being captured...

🌐 DNS Records ?DNS translates domain names to IP addresses. Records control where the site, email, and services are directed.Read more →
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A (IPv4)172.67.171.202104.21.47.180
AAAA (IPv6)2606:4700:3033::6815:2fb42606:4700:3033::ac43:abca
NSaddyson.ns.cloudflare.comalbert.ns.cloudflare.com
MX2 route1.mx.cloudflare.net52 route3.mx.cloudflare.net10 route2.mx.cloudflare.net
TXT (2)
Services configured via TXT:
Google
Show all TXT records
google-site-verification=zhPpKl7tMsApZZNF3JqHeArQBk0STFBomDjSQdXGSXM
v=spf1 include:_spf.mx.cloudflare.net ~all
📋 WHOIS / RDAP ?Public registration data: who registered the domain, when, and when it expires.Read more →
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RegistrarN/A
RegisteredN/A
ExpiresN/A
Last UpdatedN/A
🔒 SSL Certificate ?Encrypts the connection between browsers and this website. Valid SSL = HTTPS works.Read more → Valid
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Subject (CN)w3c.io
IssuerLet's Encrypt
Valid From2026-10-15
Valid Until2027-01-13 (82 days left)
SANs (2)*.w3c.iow3c.io
📡 HTTP Headers ?Metadata sent by the server: reveals software, caching rules, and security configuration.Read more →
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Status200
Servercloudflare
Content-Typetext/html; charset=utf-8
Final URLhttps://w3c.io/
strict-transport-securitymax-age=31536000
x-frame-optionsSAMEORIGIN
x-content-type-optionsnosniff
referrer-policystrict-origin-when-cross-origin
cache-controlno-cache
cf-raya4ee9c78f978b227-IAD
Security headers ?HTTP headers that protect visitors from attacks. HSTS forces HTTPS, CSP controls resource loading, X-Frame-Options prevents clickjacking.Read more →
HSTS
Content-Security-Policy
X-Frame-Options
🏠 Hosting ?Physical infrastructure: where the server is, who operates it, and what network it belongs to.Read more →
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IP Address104.21.47.180
ProviderUnknown
OrganizationN/A
ASNN/A
LocationN/A
🛡️ Security Score B (5/7)
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Valid SSL
HSTS
CSP
X-Frame-Options
X-Content-Type
Referrer-Policy
Permissions-Policy
🗺️ Sitemap & Robots
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Open to search engines
This site's robots.txt lets crawlers access its main content. Search engines can index it normally.
🤖
AI crawlers restricted — OAI-SearchBot, ChatGPT-User, PerplexityBot
No paths are disallowed — everything is crawlable.
Sitemap Found 150 pages
Last modified 2026-10-23
🔗 Social & Meta Tags Complete
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TitleW3C.io — 웹 표준부터 AI 시대의 개발까지
DescriptionHTML·CSS·JavaScript·TypeScript부터 백엔드, 접근성, AI·LLM 개발까지 웹 표준 기반 실무 지식을 정리합니다.
OG TitleW3C.io — 웹 표준부터 AI 시대의 개발까지
OG DescriptionHTML·CSS·JavaScript·TypeScript부터 백엔드, 접근성, AI·LLM 개발까지 웹 표준 기반 실무 지식을 정리합니다.
OG Imagehttps://w3c.io/og/home.jpg
OG preview
OG Typewebsite
OG Site NameW3C.io
Twitter Cardsummary_large_image
Canonical URLhttps://w3c.io/
Languageko
📧 Mail Security ?Email authentication records (SPF & DMARC) that prevent spoofing and phishing from this domain.Read more →
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SPF✓ Present
v=spf1 include:_spf.mx.cloudflare.net ~all
DMARCNot set
MX Records
2 → route1.mx.cloudflare.net
52 → route3.mx.cloudflare.net
10 → route2.mx.cloudflare.net
🌍 Other TLDs ?Other top-level domain variants of this domain name and their availability. 16 active 5 for sale 2 available
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.com ●
.net ●
.org ●
.info taken
.io current
.co ●
.dev Available
.app ●
.me taken
.biz ●
.eu ●
.xyz taken
.fi ●
.se ●
.de taken
.uk ●
.fr ●
.nl taken
.es ●
.it ●
.us ●
.ca ●
.com.au Available
.co.uk ●
📡 Uptime Monitor
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Not checked yet — data will appear after the first monitoring run.