Learn what an email header is, why it matters, and how to retrieve it from different email providers for troubleshooting deliverability issues.
Why email headers are important
Email headers contain detailed technical information about a message, including:
The path the email took to reach the inbox
Authentication results (SPF, DKIM, DMARC)
Sending server details
Timestamp and routing data
This information is essential when diagnosing issues like:
Emails going to spam
Delivery failures
Authentication misconfigurations
For deeper troubleshooting, see:
What is an email header?
An email header is the behind-the-scenes data attached to every email.
While inboxes show a simplified version (sender name, subject, etc.), the full header includes:
From and reply-to address
Recipient details
Sending domain and server
Authentication status (SPF, DKIM, DMARC)
Routing history across mail servers
This helps identify exactly how an email was processed and evaluated by inbox providers.
When you may need an email header
You may be asked to provide an email header when:
Investigating spam placement
Debugging authentication issues
Reviewing delivery failures
Working with support or compliance teams
How to get your email header
Below are step-by-step instructions based on your email provider.
Gmail (Google Workspace / Gmail)
Open the email you want to inspect.
Click the three-dot menu next to the reply button and select Show original.
A new tab will open with the full header. Copy or download the header and share it.
AOL
Open the email
Click More
Select View Message Source
A new window will display the full header
Copy and share the content
Outlook / Hotmail / Outlook 365 (Web)
Open the email
Click the options menu next to the sender name
Select View message source
The full header will appear in a pop-up
Copy and share the header
Yahoo Mail
Open the email
Click More
Select View Raw Message
A new tab will open with the full header
Copy and share the details
Apple Mail (Mac)
Open the email
Click View in the top menu
Select Message → Raw Source
A new window will display the header
Copy and share the content
Pro tip
When sharing an email header:
Send the full, unedited header
Avoid screenshots — use copy/paste for accuracy
Include the original email context if possible
How this helps with deliverability
Analyzing email headers allows you to:
Verify authentication setup (SPF, DKIM, DMARC)
Identify sending domain mismatches
Detect spam filtering triggers
Trace delivery routes and failures
Pair this with:
Key takeaway
Email headers are one of the most powerful tools for diagnosing deliverability issues.
If something goes wrong, the header tells the full story:
Where the email came from
How it was processed
Why it may have failed