Email Header Analyzer
When a specific email lands in spam and you need to know exactly why, the headers are the evidence. Paste your raw email headers to trace the message route, check authentication, and see where delivery failed.
From
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To
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Subject
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Date
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Authentication Results
Additional Details
Message Route
All Headers
Understanding Email Headers
What are email headers?
Email headers are metadata attached to every email containing routing information, authentication results, timestamps, and server details. They're like a postal tracking slip showing every server that handled your email.
What do the authentication results mean?
SPF verifies the sending server is authorized. DKIM verifies the message wasn't altered in transit. DMARC aligns SPF and DKIM with the visible From address. All three passing means maximum trust.
Why are there delays between hops?
Each Received header represents a server that processed the email. Delays can indicate spam filtering, greylisting, server load, or network issues. Large delays (>30 seconds) may affect time-sensitive emails.
What is the Return-Path?
The Return-Path (also called envelope sender or bounce address) is where bounce notifications are sent. It's different from the visible From address and is used in SPF evaluation.
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Why We Built This Tool
When a specific email fails, the headers hold the evidence — but raw headers are cryptic. Sent/received timestamps are jumbled, SPF results are buried in authentication headers, and server delays are invisible. This tool normalizes headers so you can trace the route and see exactly where delivery failed: SPF, DKIM, greylisting, or reputation blocking.
What Goes Wrong Without This
Header debugging is manual and slow. Teams copy-paste raw headers into notepad, squint at timestamps, and guess which hop failed. A 2-hour delay between hop 3 and hop 4 might indicate greylisting or ISP filtering, but without the tool, teams don't see it. Parsing headers manually wastes time; visual analysis prevents diagnostic dead ends.
Who This Tool Is For
E-commerce & DTC Brands
Marketing and technical teams debugging why specific campaigns landed in spam — tracing headers to pinpoint authentication, reputation, or server-side failures.
Email Marketing Agencies
Technical support teams auditing client header data to diagnose delivery failures and train clients on reading authentication results for self-service troubleshooting.
B2B SaaS & Outbound Teams
Developers and DevOps engineers investigating transactional mail failures, SPF/DKIM alignment issues, and message routing problems for notification systems.
Frequently Asked Questions
What are email headers?
What do SPF, DKIM, and DMARC mean in headers?
What do delays between hops mean?
Do I need an InboxEagle account to use this tool?
Manual Analysis Shows One Email. InboxEagle Shows Every Email.
Stop running manual checks. InboxEagle monitors your sender reputation, authentication, and blacklist status 24/7 — and alerts you the moment something breaks.
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