Free Email Header Analyzer
Analyze raw email headers to audit SPF, DKIM, and DMARC authentication. Trace server delivery hops, diagnose SMTP latency bottlenecks, verify in-transit TLS encryption, and audit RFC 8058 one-click unsubscribe headers.
How to View and Interpret Raw Email Headers
Behind every email lies a technical audit trail known as Internet Message Headers (RFC 5322). While email clients hide these headers by default, extracting and reading them is the single most effective way to verify if an email is authentic, identify spam traps, trace sender IP addresses, and measure relay delays across the internet.
How to Get Headers from Popular Email Apps
Gmail / Google Workspace
- Open the email message.
- Click the 3 dots (More) next to Reply.
- Select Show original.
- Click Copy to clipboard.
Microsoft Outlook
- In Outlook Web, click the 3 dots (...) on the email.
- Select View > View message details.
- In Outlook Desktop: File > Properties.
- Copy the Internet headers box.
Apple Mail (macOS)
- Select the email in Apple Mail.
- In the menu, choose View > Message.
- Click All Headers (or Shift + Cmd + H).
- Select all header lines and copy.
Yahoo Mail
- Open the email in Yahoo Mail.
- Click the 3 dots (More) icon above the email.
- Select View raw message.
- Copy all headers above the message body.
The 4 Pillars of Email Header Authentication
When analyzing headers, the Authentication-Resultsline is the definitive record of how the recipient's server evaluated the message:
1. SPF (Sender Policy Framework)spf=pass
Verifies whether the sending server's IP address is listed in the DNS TXT record of the domain found in the Return-Path or smtp.mailfrom.
2. DKIM (DomainKeys Identified Mail)dkim=pass
Validates the cryptographic digital signature attached to the message. Proves that the email body and key headers were not modified or tampered with by any intermediary relay in transit.
3. DMARC Alignmentdmarc=pass
Ensures the human-visible “From:” header domain matches either the SPF authenticated domain or the DKIM signing domain. Without DMARC alignment, a message is vulnerable to spoofing.
4. ARC (Authenticated Received Chain)arc=pass
Preserves email authentication results across forwarding services and mailing lists so legitimate forwarded messages do not fail DMARC when delivered to downstream inboxes.
Frequently Asked Questions
What causes high delivery latency in email hops?▾
Delivery latency typically occurs when an intermediate mail server encounters rate limits (greylisting), large outbound queues, antivirus/antispam inspection delays, or temporary DNS resolution slowdowns. Our waterfall chart displays the exact number of seconds elapsed at each relay hop so you can spot the bottleck.
Is my email private when I paste headers into this tool?▾
Yes! All email header parsing in EmailSendy's Header Analyzer runs locally inside your browser. No header data or message contents are ever sent to, stored on, or logged by our servers.
What does Return-Path mean?▾
The Return-Path(also known as the envelope sender or bounce address) is where receiving servers send Delivery Status Notifications (DSNs) and bounce notifications if the email cannot be delivered. In authentic emails, this domain usually aligns with the sender's primary domain.
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