How to View Email Headers in Gmail
how to view email headers is the fastest way to see whether SPF, DKIM, and DMARC passed on a real message, not what your DNS panel claims.
Gmail (Web and Mobile)
Open the message in Gmail (inbox or Spam). Click the three-dot menu → Show original. A new tab opens with the full MIME source.
Use Find (Ctrl+F / Cmd+F) and search for Authentication-Results. On mail received at Gmail you usually see a block from google.com.
Read the three legs on one line or nearby lines:
spf=pass (or fail)
dkim=pass (or fail)
dmarc=pass (or fail)
Note the domains. SPF often shows which domain was authorized. DKIM shows d=yourdomain.com on a aligned signature. DMARC fails when neither leg aligns with the visible From: address.
On the Gmail app: open the message → tap the three dots → Show original (wording may vary by app version). Same search for Authentication-Results.
Outlook on the Web and Microsoft 365
Open the message in Outlook on the web. Click the three dots on the message toolbar → View → View message details (or View message source, depending on build).
Search for Authentication-Results or Received-SPF. Microsoft may list spf= and dkim= in separate header blocks.
For a message you sent from M365, you want spf=pass and dkim=pass with domains that match your From: address. Forwarded mail often breaks SPF while DKIM may survive.
Apple Mail (macOS)
Open the message. Menu View → Message → Raw Source (or All Headers).
Search Authentication-Results or dkim=pass. Apple Mail does not rewrite headers; you see what the receiving server added.
What good looks like on a test you sent yourself
Send from your work address to a personal Gmail. Show original should show spf=pass, dkim=pass, and dmarc=pass for the same brand domain in From:. One leg passing while dmarc=fail usually means alignment, not a missing DNS record.
Spam folder vs inbox
Headers tell you why a message landed in Spam, not whether your marketing tool dashboard is optimistic. Compare one inbox message and one spam message side by side. The diff in Authentication-Results beats any green check in an ESP UI.
Do not paste secrets
Headers include routing IPs, Message-IDs, and sometimes internal hostnames. Redact before you post in a ticket or public thread.
Pro tip
Frequently Asked Questions
Key takeaways
Gmail Show original is the default path for how to view email headers when you troubleshoot deliverability.
Search Authentication-Results first; read spf=, dkim=, and dmarc= together.
Compare inbox vs spam copies of the same campaign template.
Headers reflect one message path; DNS tools reflect published records. Use both.
Redact raw headers before sharing outside your team.
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