Is your email actually protected?
Is your site actually up?
MXDoctor runs the checks mail servers and browsers run — SPF, DKIM, DMARC, DNS, SSL, blacklists and uptime — live, free, and explained in plain English.
No signup. No cached data. Every check runs against live DNS, exactly as a mail server sees it.
The free diagnostic toolkit
SPF Checker
Validate an SPF record, count its DNS lookups and catch the mistakes that break email delivery.
Open tool →DMARC Checker
Check a domain's DMARC policy and grade how protected it really is against spoofing.
Open tool →DMARC Generator
Build a correct DMARC record in seconds — start at monitoring, end at reject.
Open tool →DKIM Checker
Look up a DKIM selector, verify the public key and estimate its strength.
Open tool →DNS Checker
A complete snapshot of a domain's DNS records: A, AAAA, MX, NS, TXT, SOA and CAA.
Open tool →Blacklist Checker
Check an IP address or domain against the major DNS blacklists in one go.
Open tool →SSL Checker
Check a certificate's expiry, issuer and coverage before it takes your site down.
Open tool →Website Uptime Checker
Is it down for everyone or just you? Check any website's status and response time.
Open tool →Why these checks, together?
Most email and website failures are not mysteries — they are configuration facts that nobody looked at. An SPF record that quietly grew past its 10-lookup limit when a new marketing tool was added. A DMARC record published in 2023 and left at monitoring-only ever since. A certificate whose renewal broke the day the DNS moved. A mail-server IP listed on Spamhaus because a neighbour on the same shared server got hacked. Every one of those is visible in public data, in seconds, if something bothers to look.
MXDoctor looks. Each tool here runs the same queries a receiving mail server or a browser runs, shows you the raw record next to a plain-English verdict, and tells you the concrete fix — the same standard of diagnosis we would want on our own domains. If you run a business on your domain, start with the Full Site Health Check: one scan, one score, every finding in one place.
Checking is a snapshot. Monitoring is the habit.
A clean result today says nothing about next month — records get edited, certificates tick down, IPs get listed at 3 a.m. That is why MXDoctor's tools are the free front door of UptimeVitals, our monitoring service: the same checks, every few minutes, with alerts the moment anything changes and DMARC reports translated from XML into English. The tools stay free forever. The watching is what the $5 is for.
UptimeVitals watches SPF, DKIM, DMARC, DNS, SSL and uptime around the clock and alerts you before your customers notice. From $5/mo.