Free domain checkers

Instant SPF / SPF checker, DKIM / DKIM checker, DMARC / DMARC checker, MX / MX checker, DNS A / DNS A checker, CAA vs live cert issuer, MTA-STS / MTA STS checker (decoded policy), TLS-RPT / TLS reporting, BIMI / BIMI checker, SSL, HTTP status monitoring / website HTTPS / HTTP status checker, HTTPS redirect / HSTS / X-Frame-Options / X-Content-Type-Options / security headers checker, open port scanner / open ports checker, and TTFB / TTFB checker / performance checks — no login. On fail/warn you get copy-paste DNS examples for that domain. Add it free and the same fix hints stay on domain details.

Full check / domain monitoring Domain monitoring pulse — SPF + DKIM + DMARC + MX + SSL + CAA vs live issuer (email auth flock) SPF / SPF checker SPF checker — v=spf1 include tree + 10 DNS-lookup limit, missing/+all warn DKIM / DKIM checker DKIM checker — common selectors, missing/empty public key warn DMARC / DMARC checker DMARC checker — _dmarc v=DMARC1 policy present, p=none warn, spoofing posture MX / MX checker MX checker — inbound exchangers present, priorities + hosts DNS A / DNS A checker DNS A checker — does the hostname still have an IPv4 A record Apex / monitoring Apex monitoring — A/AAAA at the bare domain + CNAME-at-apex warning CAA record / tester CAA record checker / CAA tester — allow-list present + does it permit the live TLS issuer MTA-STS / MTA STS checker MTA-STS checker / MTA STS checker — DNS id + HTTPS policy (mode, mx, max_age) still live TLS-RPT / TLS reporting TLS-RPT checker / TLS reporting — _smtp._tls v=TLSRPTv1 rua still published BIMI / BIMI checker BIMI checker — default._bimi v=BIMI1 inbox brand-mark DNS still published SSL / expired / monitoring SSL days left or expired + live issuer (pair with CAA) HTTP status monitoring / website HTTPS HTTP status monitoring checker — HTTPS status code + title Expiry / WHOIS monitoring Domain expiry monitoring — registration runway via public RDAP/WHOIS path HTTPS redirect / HSTS / X-Frame-Options / X-Content-Type-Options / security headers HTTPS redirect / HSTS / X-Frame-Options / X-Content-Type-Options / security headers checker — force HTTPS, Strict-Transport-Security, clickjacking, nosniff still live Open port scanner / open ports checker Open port scanner — risky FTP, Telnet, MySQL, Postgres, Redis, MongoDB still answering on the public hostname TTFB / TTFB checker / performance TTFB checker — Time to First Byte / website performance monitoring pulse still sane

Guides

Plain English on what each record means.

Pair a free check with a short guide: domain monitoring, email authentication monitoring, email authentication, SPF / SPF checker, SPF monitoring, DKIM / DKIM checker, DKIM monitoring, DMARC / DMARC checker, DMARC monitoring, MX / MX checker, MX monitoring, DNS A / DNS A checker, DNS monitoring, apex monitoring, apex / zone apex, CNAME at apex, CAA record, CAA monitoring, MTA-STS / MTA STS checker, MTA-STS monitoring, BIMI / BIMI checker, BIMI monitoring, SSL certificate monitoring, SSL certificate expired, domain expiry / WHOIS monitoring, domain expiry (RDAP), HSTS / HSTS checker, security headers monitoring, X-Frame-Options / X-Frame-Options checker, X-Content-Type-Options / nosniff, HTTPS redirect / HTTPS redirect checker, open ports / open port scanner / open ports checker, security headers & open ports, TLS-RPT / TLS reporting, TLS-RPT monitoring, website monitoring / website monitoring checker, uptime monitoring / uptime monitoring checker, HTTP status monitoring / HTTP status monitoring checker, TTFB / TTFB checker, website performance monitoring, performance.

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