Email

Check the records that authorize your mail, read message headers, and work out why a message failed.

SPF/DKIM/DMARC

SPF Checker Mechanism breakdown, full resolution tree, and the 10-lookup limit.

DKIM Checker Look up a key by selector name: resolution path, tags, and revoked-vs-broken status.

DMARC Checker Full tag table, policy findings, and reporting guidance.

DMARC Report Viewer Turn raw DMARC XML reports into something readable. runs locally

Deliverability

Email Deliverability Test Find out whether your mail will land in the inbox — and why.

Email Header Analyzer Paste raw headers and trace a message's full delivery path. beta

SMTP Test Connect to a mail server and watch the live SMTP/STARTTLS handshake as it happens.

Why Did This Email Fail? Translate a bounce message into plain English and next steps. ai-assisted

Blacklist Check See if your domain or IP is listed on major spam blocklists.

Other

SafeLinks Decoder Turn a rewritten email link back into the URL it points at. beta runs locally