Free Security Tools
Instant, no-signup security checks for any domain. Built by the team behind Xentinel's continuous attack surface monitoring platform.
SSL Certificate Checker
Check SSL validity, expiration, issuer, TLS version, and SANs for any domain.
PopularSecurity Headers Checker
Get an A–F grade on CSP, HSTS, X-Frame-Options, and 5 more security headers.
DNS Lookup
Query A, AAAA, MX, TXT, NS, and CNAME records for any domain instantly.
Subdomain Finder
Discover all subdomains using Certificate Transparency logs. Find shadow IT.
WHOIS Lookup
Check domain registration, expiration date, registrar, and nameservers via RDAP.
SPF, DMARC & DKIM Checker
Validate email security records. Find misconfigurations that allow spoofing.
HTTP Headers Inspector
View all response headers, follow redirect chains, and detect stack exposure.
Want continuous monitoring?
These tools run on-demand. Xentinel runs them automatically 24/7 across all your assets and alerts you the moment something changes.
See Plans — from $149/mo