substack.com 200
🔒 SSL Valid
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 61d
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 →
Cloudflare
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 →
104.18.37.200
Tech Stack Technologies detected on this website: CMS, frameworks, libraries, CDN, and analytics tools. 4
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📊 Analytics
Google Analytics
🌐 CDN
Cloudflare
🔤 Font/Icon
Google Fonts
⚙️ Framework
Express
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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) | 104.18.37.200172.64.150.56 |
| AAAA (IPv6) | 2606:4700:4401::ac40:96382606:4700:4404::6812:25c8 |
| NS | ali.ns.cloudflare.comlee.ns.cloudflare.com |
| MX | 10 mxb.mailgun.org10 mxa.mailgun.org |
| TXT | tiktok-developers-site-verification=A9XRSo8lWy5CPFJ0bqI04KCpUZGAAq7p v=spf1 include:_spf.google.com include:mailgun.org include:mail.zendesk.com ~all facebook-domain-verification=8vbxp2ntmkudc6is3h5r840c9fwo7f google-site-verification=4V_X38Yf0J4VJcWFwtG38bOS1nkOWeIWJhticlMgNQE google-site-verification=DAkdykID6WqQM6tT7IfSu9_uB7-qIdB039MA_C3T3eA google-site-verification=FfNIQIxsRHpj3Y7E_d3N6GFqGgWDZ-sfYojqCilwtqE google-site-verification=SXEl7_p4SBszcanSWwVc_3-RFky80c0-94janbeeWI4 google-site-verification=vQEKLOUDfKNOQAv9W3EUMiRD6e5ibAEPhc2yCzP7big tiktok-developers-site-verification=7PgqCAJ52ILLOqf2KELd8uaRfJpuzaLQ |
WHOIS / RDAP Public registration data: who registered the domain, when, and when it expires.Read more →
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| Registrar | N/A |
| Registered | N/A |
| Expires | N/A |
| Last Updated | N/A |
SSL Certificate Encrypts the connection between browsers and this website. Valid SSL = HTTPS works.Read more → Valid
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| Subject (CN) | substack.com |
| Issuer | Google Trust Services |
| Valid From | 2026-07-22 |
| Valid Until | 2026-10-20 (61 days left) |
| SANs (2) | substack.com*.substack.com |
HTTP Headers Metadata sent by the server: reveals software, caching rules, and security configuration.Read more →
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| Status | 200 |
| Server | cloudflare |
| Content-Type | text/html; charset=utf-8 |
| x-powered-by | Express |
| strict-transport-security | max-age=31536000; includeSubDomains; preload |
| content-security-policy | frame-ancestors 'self' https://*.substack.com https://substack.com |
| cache-control | no-cache |
| cf-ray | a2de1c786e5da727-IAD |
Security headers HTTP headers that protect visitors from attacks. HSTS forces HTTPS, CSP controls resource loading, X-Frame-Options prevents clickjacking.Read more →
Hosting Physical infrastructure: where the server is, who operates it, and what network it belongs to.Read more →
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| IP Address | 104.18.37.200 |
| Provider | Cloudflare |
| Organization | Cloudflare, Inc. |
| ASN | AS13335 |
| Country | US |
| City | San Francisco |
Security Score
D (3/7)
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Sitemap & Robots
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| robots.txt | Found Blocked |
| Sitemap | Found 11 sitemaps (index) pages |
| Disallowed paths |
/
/action/
/publish
/sign-in
/channel-frame
/session-attribution-frame
/visited-surface-frame
/feed/private
/feed/podcast/*/private/*.rss
/subscribe
... +5 more |
Social & Meta Tags
Complete
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| Title | Substack |
| Description | The app for independent voices |
| OG Title | Substack |
| OG Description | The app for independent voices |
| OG Image | https://substackcdn.com/image/fetch/$s_!Xim-!,w_400,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack.com%2Ficons%2Fsubstack%2Ficon.svg |
| OG Type | article |
| Twitter Card | summary |
| Canonical URL | https://substack.com/ |
| Language | en |
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.google.com include:mailgun.org include:mail.zendesk.com ~all |
| DMARC | ✓ Present v=DMARC1; p=reject; pct=100; rua=mailto:[email protected]; sp=reject; aspf=r; |
| MX Records | 10 → mxb.mailgun.org 10 → mxa.mailgun.org |