Free email tools

The checks we run for our own relay fleet, opened up. No account, no signup.

SMTP testerConnect to any SMTP server from our network: greeting, EHLO capabilities, STARTTLS certificate, and whether your login works — with the exact server replies. SPF, DKIM & DMARC checkerLook up a domain's MX, SPF (with the 10-lookup count), DKIM selectors and DMARC policy, and see what to add.

Need the settings for a specific provider? See SMTP settings for every provider. Got an error code? See SMTP errors explained.