🌐
substack.dev 404
🔒 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 →
404
SSL Expires When the SSL certificate expires. An expired certificate causes browser security warnings.Read more →
in 59d
Domain Expires When the domain registration expires. If not renewed, the domain becomes available to others.Read more →
in 1986d
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 →
0/3
IP Address The numerical address of the server hosting this website. Reveals location, provider, and network.Read more →
104.21.9.156
Performance Lighthouse performance score from Google PageSpeed Insights (0–100). Measures real-world loading speed, interactivity and visual stability.
N/A
Uptime
100%
Performance Lighthouse performance score from Google PageSpeed Insights (0–100). Measures real-world loading speed, interactivity and visual stability.
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Mobile
Score
Accessibility
Best Practices
SEO
CLS
0.000
TTFB
0.00s
Desktop
Score
Accessibility
Best Practices
SEO
CLS
0.000
TTFB
0.00s
Checked: 2026-09-05 21:58:00.740246 · View on PageSpeed
Tech Stack Technologies detected on this website: CMS, frameworks, libraries, CDN, and analytics tools. 2
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🌐 CDN
Cloudflare
☁️ Hosting
AWS
Screenshot
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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) | 104.21.9.156172.67.160.67 |
| AAAA (IPv6) | 2606:4700:3030::ac43:a0432606:4700:3031::6815:99c |
| NS | ali.ns.cloudflare.comlee.ns.cloudflare.com |
WHOIS / RDAP Public registration data: who registered the domain, when, and when it expires.Read more →
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| Registrar | Squarespace Domains II LLC. |
| Registered | 2022-03-24 |
| Expires | 2032-03-24 (in 1986 days) |
| Last Updated | 2025-10-10 |
| Status | client delete prohibitedclient transfer prohibited |
SSL Certificate Encrypts the connection between browsers and this website. Valid SSL = HTTPS works.Read more → Valid
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| Subject (CN) | substack.dev |
| Issuer | Google Trust Services |
| Valid From | 2026-09-15 |
| Valid Until | 2026-12-14 (59 days left) |
| SANs (2) | substack.dev*.substack.dev |
HTTP Headers Metadata sent by the server: reveals software, caching rules, and security configuration.Read more →
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| Status | 404 |
| Server | cloudflare |
| Content-Type | text/html; charset=utf-8 |
| Final URL | https://substack.dev/ |
| cache-control | no-cache, no-store |
| cf-ray | a4b469140d680606-IAD |
| x-cache | Error from cloudfront |
| via | 1.1 heroku-router, 1.1 7d1db1c7d462961e6d2df897111dc088.cloudfront.net (CloudFront) |
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 | 104.21.9.156 |
| Provider | Unknown |
| Organization | N/A |
| ASN | N/A |
| Location | N/A |
Security Score
F (1/7)
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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.
No paths are disallowed — everything is crawlable.
| Sitemap | Not found |
Social & Meta Tags
Missing
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| Title | No such app |
Mail Security Email authentication records (SPF & DMARC) that prevent spoofing and phishing from this domain.Read more →
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| SPF | Not set |
| DMARC | Not set |
Other TLDs Other top-level domain variants of this domain name and their availability. 20 active 3 for sale
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Uptime Monitor
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| Current Status | 🟢 Client Error |
| HTTP Status | 404 |
| Response Time | 537ms |
| Last Checked | 2026-10-16 01:46:33.516365 |
| Uptime (30d) | 100% |
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