Question 1

What are email headers?

Accepted Answer

Email headers are metadata attached to every email that describe how the message was routed, who sent it, authentication results, and more. They're like a postal stamp trail — each server that handles the email adds its own header.

Question 2

How do I find raw email headers?

Accepted Answer

In Gmail: Open the email → click the three dots → 'Show original'. In Outlook: Open the email → File → Properties → 'Internet headers'. In Apple Mail: View → Message → All Headers. Copy the entire header block and paste it into this tool.

Question 3

What do SPF, DKIM, and DMARC mean?

Accepted Answer

SPF (Sender Policy Framework) verifies that the sending server is authorized to send on behalf of the domain. DKIM (DomainKeys Identified Mail) verifies the email wasn't tampered with using a cryptographic signature. DMARC (Domain-based Message Authentication, Reporting, and Conformance) ties SPF and DKIM together with a policy for handling failures.

Question 4

Why does authentication matter for cold email?

Accepted Answer

Email providers like Gmail and Outlook use SPF, DKIM, and DMARC results to decide whether to deliver your email to the inbox, spam, or reject it entirely. Failing any of these checks dramatically reduces your deliverability. For cold email, passing all three is non-negotiable.

Question 5

What are Received headers?

Accepted Answer

Each mail server that handles your email adds a 'Received' header. Reading them in order shows you the exact route your email took from sender to recipient. This is useful for diagnosing delivery delays and identifying suspicious relays.

Email Header Analyzer

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