Free DNS and email tools
Check a domain or URL instantly. All tools use the same checks as DomainWarn monitoring and query DNS directly at the authoritative name server.
Domain Check
Check website, email, DNS and domain in one run: 20 checks, a score from 0 to 100 per area and overall, with recommendations. Free, no sign-up required.
Open tool →Email header analyzer
Paste email headers and read them in plain words: did SPF, DKIM and DMARC pass, does the sender domain align, which servers relayed it, how long it took?
Open tool →Privacy check
Check for free which third parties your home page loads before any consent: Google Fonts, Analytics, pixels, maps – with a note on what is legally risky.
Open tool →security.txt Checker
Check your security.txt for free: Contact, Expires, expiry date, HTTPS and content type per RFC 9116. See whether security researchers can reach you.
Open tool →Website Check
Check a website for free: robots.txt, XML sitemap, broken pages, dead links, accidental noindex and canonical tags – up to 20 URLs in one run.
Open tool →Email Check
Check SPF, DKIM, DMARC and MX of a domain in one run, free and without sign-up. Shows whether your mail meets the Google and Yahoo sender requirements.
Open tool →SPF Checker
Free SPF record check and lookup: syntax, includes, the 10 DNS lookup limit and the closing qualifier. Shows whether your domain blocks forged senders.
Open tool →DMARC Checker
Free DMARC record check: policy (none, quarantine, reject), pct, reporting addresses and syntax errors. With recommendations for moving to p=reject.
Open tool →DNS Checker
Free DNS lookup straight from the authoritative name server: A, AAAA, CNAME, MX, TXT, NS and CAA records at a glance. No sign-up, every record explained.
Open tool →MX Checker
Free MX lookup: which mail servers receive for a domain, do they resolve, is the priority right? Detects missing and unreachable mail servers.
Open tool →SSL Checker
Free SSL certificate check: expiry date, issuer, chain, host name and TLS version, mail servers too. Detects expired, self-signed and mismatched certificates.
Open tool →HTTP Header Checker
Free HTTP header check: HSTS, Content-Security-Policy, X-Content-Type-Options, X-Frame-Options, Referrer-Policy and Permissions-Policy, with fixes.
Open tool →Is the website down?
Website not loading? Check for free whether a site is down for everyone or just for you: response, status code, load time, redirects and IP addresses.
Open tool →DNS Propagation Checker
Check DNS propagation for free: which resolvers worldwide (Google, Cloudflare, Quad9 …) already return the new A, MX or TXT record, which still the old one?
Open tool →Redirect Checker
Free 301 redirect check: every hop with status code and response time, from http to https, from www to non-www. Detects redirect chains, loops and 302s.
Open tool →DKIM Checker
Free DKIM record check and lookup: selector, key type, key length, syntax and revoked keys. Leave the selector empty to try common selectors automatically.
Open tool →DNSSEC Checker
Free DNSSEC test: DS record, resolver validation and broken signature chains. Shows whether validating resolvers like Google and Cloudflare still reach you.
Open tool →Name Server Check
Free name server check: does every NS answer authoritatively, do all serve the same zone data, are they in different networks? Finds lame delegation.
Open tool →CAA Record Checker
Free CAA record check: issue, issuewild and iodef, matched against the CA of your current certificate. Shows whether the next renewal is going to fail.
Open tool →IPv6 Check
Free check of the AAAA records for the domain and www and, where the checking location has IPv6, a fetch over every IPv6 address. Finds dead records.
Open tool →HTTP/3 Check
Check for free whether your website advertises HTTP/3 via Alt-Svc and actually answers over QUIC (UDP 443). Finds blocked UDP ports and stale headers.
Open tool →MTA-STS Checker
Free MTA-STS check: DNS record, policy file, mode, max_age and whether your MX servers are covered. Shows whether inbound mail enforces TLS.
Open tool →TLS-RPT Checker
Free TLS-RPT record check: syntax, reporting addresses (rua) and common errors such as a missing record. Shows whether you get reports on TLS failures.
Open tool →BIMI Checker
Free BIMI record check: syntax, logo URL, SVG Tiny PS, VMC certificate and the DMARC prerequisite. Shows why your logo does not appear in Gmail.
Open tool →Blacklist Check
Free IP and domain blacklist check: mail server IPs, website IP and domain against Spamhaus, Spamcop, Barracuda, PSBL and SURBL. With delisting links.
Open tool →Domain Checker
Free domain check: WHOIS data via RDAP straight from the registry, expiry date, registrar, EPP status, transfer lock and name servers. Warns before expiry.
Open tool →Guides
For every tool the matching guides from daily agency work with client domains. Each one ends with a concrete record or a checklist.