Free email tools
Check SPF, DKIM, DMARC and MX records, read email headers, test for spam and verify addresses. No sign-up, no limits.
Check your domain
The DNS records that decide whether your email is trusted.
Check a message
Before you send it, or after it went somewhere it should not have.
When the records check out, send with Plunk.
Plunk sets up SPF and DKIM with you and tracks your sending reputation from the first email.