Free domain email-security checker

Spamless offers a free, no-signup tool to check any domain's inbound email-security posture: spamless.dev/check.

What it checks

You enter a domain (e.g. example.com) and we look up its public DNS records and grade them:

• MX — is mail configured?
• SPF — is sender authentication present and restrictive (does it end in -all / ~all)?
• DMARC — is anti-spoofing enforced (p=quarantine / p=reject) or only monitoring (p=none)?
• MTA-STS — is inbound mail forced over TLS?

What you get

• An overall letter grade (A–F) and score (0–100) — A from 90, B from 75, C from 55, D from 35, F below that.
• A per-check breakdown (pass / warning / fail) with plain-language recommendations on what to fix.

Privacy & limits

• It reads public DNS records only — no mail is sent, received or stored, and the tool needs no account.
• Results are cached for about an hour, so re-running a check right after a DNS change may still show the previous result.
• It's rate-limited (a handful of checks a minute per visitor) to keep it fair for everyone.

Why it matters

Most domains have gaps (commonly a missing or unenforced DMARC), which is exactly what attackers exploit for phishing. The checker shows you the gaps; Spamless helps you close them and filters threats before they reach your inbox.

For the background, see SPF, DKIM & DMARC explained.