● Free tool · Email security
Email Security Checker
Is your domain protected against spoofing? This checks your SPF, DKIM, and DMARC records and explains, in plain English, what's set up and what to fix. No account, nothing installed — it runs entirely in your browser.
Just the domain — e.g. acme.com (no https://, no @).
DKIM can't be auto-found — pick or type your selector.
🔒 Private by design. Your domain is sent straight from your browser to a public DNS resolver (Cloudflare 1.1.1.1, with Google 8.8.8.8 as backup). ByTE X Bit never sees what you check — there's no server in the middle.
SPF
Who's allowed to send
DKIM
Cryptographic signature
DMARC
What to do with failures
What these three do
- SPF
- Lists which mail servers are allowed to send email for your domain. Stops outsiders from sending as you.
- DKIM
- Adds a cryptographic signature to your outgoing mail so receivers can confirm it wasn't forged or altered.
- DMARC
- Ties SPF and DKIM together and tells receiving servers what to do with mail that fails — and sends you reports.