Email Header Analyzer
Extract authentication results, analyze hop delays, detect domain alignment issues, and run live DNS checks.
Upload or Paste Headers
Drag and drop your .eml file here, or simply paste the raw header text below.
Understanding Email Headers & Diagnostics
Email headers contain the hidden metadata of an email's journey. Analyzing them is crucial for diagnosing deliverability issues, identifying spoofing, and resolving inbox placement failures.
What are Email Headers?
Email headers are the technical routing instructions and metadata attached to every email. While most email clients (like Gmail or Outlook) hide them, they contain vital information including the sender's IP address, the route the email took across the internet, spam filter scores, and authentication results. To view them, look for options like "Show original" or "View source" in your email client.
Authentication Results Explained
The Authentication-Results header is injected by the final receiving server (e.g., Google Workspace) after it evaluates the email. It tells you exactly whether the email passed or failed SPF, DKIM, and DMARC checks. If an email goes to spam, this is the first place you should check to see if your DNS infrastructure is correctly configured and aligned.
Analyzing Hop Delays
Every time an email passes through a Mail Transfer Agent (MTA) or security gateway, a new Received header is added to the top of the chain. By analyzing the timestamps on these headers from bottom (origin) to top (destination), you can calculate "hop delays." If an email takes hours to arrive, hop analysis will reveal exactly which server in the chain held onto the message and caused the bottleneck.
Domain Alignment Failures
One of the most common causes of DMARC failure is domain misalignment. This occurs when the visible "From" domain does not match the hidden "Return-Path" (Envelope From) domain. Our analyzer automatically checks for this discrepancy, which frequently happens when using third-party marketing tools (like Mailchimp or Hubspot) without properly configuring custom bounce domains.