Free email header analyzer
Trace your email's delivery path and check SPF, DKIM, and DMARC authentication.
Paste raw email headers below, or drop an EML file. Or, see a sample.
Got a bounce message? Paste the whole thing – we’ll explain any error codes it contains.
No registration or email required. This tool runs locally in your browser — your data is never uploaded anywhere.
What are email headers?
Every email contains hidden metadata known as headers that record its journey from sender to recipient. Headers include authentication results (SPF, DKIM, DMARC), the routing path through mail servers, timestamps, and metadata about the sending software. Analyzing headers is useful for tracing spam, diagnosing delivery failures, and verifying that your email authentication is configured correctly.
How to get raw email headers:
- Gmail: Open the email, click the three-dot menu (⋮) and select Show original. Copy all the text from the new tab.
- Outlook on the web: Open the email, click the three-dot menu and select View → View message source.
- Outlook desktop: Open the email, click File → Properties and look for the Internet headers box.
- Apple Mail: Open the email and select View → Message → All Headers, or press ⇧⌘H.
- Thunderbird: Open the email and select View → Message Source, or press Ctrl+U.
Want to check your domain's DNS records directly? Use our SPF, DKIM, and DMARC checker.
A free tool provided by Auth-Email
Auth-Email makes your Gmail, Outlook, or other OAuth 2.0 email account available to any IMAP, POP3, or SMTP email client — no app passwords or special configuration needed.
Frequently asked questions
How do I find my email’s headers?
In Gmail, open the message, click the three-dot menu and choose Show original. In Outlook on the web, choose View → View message source. In Outlook desktop, open File → Properties. In Apple Mail, choose View → Message → All Headers.
Why did my email fail SPF, DKIM or DMARC?
SPF fails when the sending server isn’t listed in your domain’s SPF record. DKIM fails when a message has no signature or was changed after signing. DMARC fails when neither SPF nor DKIM passes for the domain in the From address. Use our DNS record checker to check your domain’s configuration.