Tools

Each of these runs the same engine. They differ in what they explain.

Reads your DMARC record, resolves the policy that actually applies, and reports what conforming receivers will do with it.

Parses your SPF record, resolves the full include chain, and shows exactly how many of the ten permitted DNS lookups you use and where they go.

Fetches your published policy over HTTPS exactly as a sending server would, then cross-checks it against your live MX records.

Validates the record that asks sending servers to tell you when TLS negotiation to your mail servers fails.

One scan covering every check, with the record we read and the standard the rule comes from attached to each result.