Check why your email lands in spam

Most spam-folder problems that come from configuration — as opposed to content or sending reputation — are visible in DNS. This checks the authentication records that receivers use to decide, and tells you which are missing.

What this means

What does this check, and what does it not?

It checks the authentication setup a receiver evaluates: SPF, DKIM, DMARC, and transport security. It cannot see your sending reputation, complaint rate, list hygiene, or message content — all of which also matter. Configuration is simply the part that is fixable in an afternoon.

I pass SPF and DKIM but still land in spam.

Then the cause is usually reputation or content, not configuration. Common culprits: sending to addresses that bounce (which is what the verification API prevents), a sudden volume increase on a cold domain, or spam complaints.

Do bulk senders require this now?

Google and Yahoo both require SPF, DKIM and DMARC for bulk senders. Without them mail is rejected or filtered regardless of content.