Domain Security Checker
Get a one-page security overview of any domain. The checker combines DNS and email authentication (SPF, DMARC, DNSSEC, CAA, MX), HTTPS (certificate, TLS versions, redirect, HSTS) and the security headers grade into a single score with the most important fixes first.
Enter a domain and we run the DNS checks through DNS-over-HTTPS, a TLS handshake, and a headers scan in parallel, then combine them into a domain security score. Each check links to what it means and how to fix it; use the dedicated SPF, DMARC, SSL and headers tools for detail.
Instant Results
Live checks in seconds
Nothing Stored
No logs of what you check
No Sign-Up
Free, no credits or email
Suggest a Feature or Improvement for Domain Security Checker
Need custom options, higher limits, or extra format support? Let our engineering team know!
How to use Domain Security Checker
- 1Enter the domain.
- 2Review the score and failed checks.
- 3Fix email authentication (SPF, DMARC) and HTTPS issues first.
- 4Re-scan to confirm improvements.
What the scan covers
Email spoofing protection (SPF records and a DMARC policy), DNS integrity (DNSSEC) and certificate-issuance control (CAA), plus the HTTPS basics: a trusted, unexpired certificate, no deprecated TLS versions, HTTP-to-HTTPS redirect, HSTS and security headers.
Domains that don't send email should still publish “v=spf1 -all” and a p=reject DMARC record, otherwise they're easy to spoof.
Dig deeper
See each area in detail with the SPF Record Checker, DMARC Record Checker, DNSSEC Checker, SSL Checker and Security Headers Checker.
Frequently Asked Questions
Is this a vulnerability scan?
No. It checks publicly visible configuration. It doesn't probe for software vulnerabilities or attack the site.
What do you do with the domains and URLs I check?
Our server performs the lookup once and returns the result to your browser. We don't store the addresses you check or build a history. Private and internal addresses are blocked.
Is it free? Do I need an account?
It's completely free with no sign-up and no daily credits.
Guides & Tutorials
Related Tools
SPF Record Checker
Validate a domain's SPF record, count DNS lookups against the limit of 10, and see the include tree.
DMARC Record Checker
Check a domain's DMARC policy, reporting and alignment — and get a starter record if it's missing.
SSL Checker
Check a site's SSL/TLS certificate, chain, expiry, TLS versions, HTTPS redirect and HSTS.