Email Domain Health Checker
Test every record that decides whether your email lands in the inbox: MX, SPF, DKIM, DMARC, BIMI and reverse DNS. Get an A-F grade and a list of exact fixes.
How it works
Gmail, Yahoo and Microsoft now require authenticated mail. A domain missing SPF, DKIM or DMARC sees more spam-folder placement and outright rejections, especially above 5,000 messages a day.
This report runs every check in parallel: it confirms your mail servers resolve, counts SPF lookups against the limit of 10, probes over 40 common DKIM selectors and checks key strength, reads your DMARC policy, validates BIMI, and confirms reverse DNS on your primary mail server.
Share the result: the URL of this page includes the domain, so you can send the report to a client or teammate.
Automate it with the API
Run this check for every address in your product, from any language.
curl -X POST "https://www.mailrambo.com/v1/verify?detail=full" \
-H "Authorization: Bearer $MAILRAMBO_KEY" \
-H "Content-Type: application/json" \
-d '{"email": "jane@acme.com"}'
# -> detail.dns: { spf, dmarc_policy, dkim_selectors, bimi, ptr, mx_hosts }API reference · Get a free API key
Frequently asked questions
What is a good email domain health score?
A or B means SPF, DKIM and DMARC are in place and enforced. C or lower usually means DMARC is only monitoring (p=none) or DKIM is missing - both are fixable in DNS in a few minutes.
Why is DKIM not found for my domain?
DKIM keys live under a selector name that only your sending provider knows. We probe over 40 common selectors; if yours is custom (ZeptoMail, Zoho and Postmark often use numbers or dates), enter it in the optional selector field. Find it in your provider's DNS settings, or in the s= tag of the DKIM-Signature header of an email you sent.
Does this send any email?
No. Every check is a public DNS lookup. Nothing is sent and nothing is stored.
Is it free?
Yes, with no signup. To run these checks automatically for every address in your product, use the MailRambo API with ?detail=full.
Related tools
SPF Record Checker
Validate SPF and count DNS lookups against the 10-lookup limit.
DKIM Record Checker
Find and validate DKIM keys, including key length and revoked selectors.
DMARC Record Checker
Read your DMARC policy, reporting and enforcement level.
MX Record Lookup
See a domain's mail servers, priorities and email provider.
Run these checks from your code
Verify addresses at signup, clean lists and read SPF/DKIM/DMARC with one API call. 100 free verifications a month, test keys that cost nothing, and the API on every plan.