Email Header Analyzer
Unfold email headers, decode MIME encoded words and inspect a chronological Received chain with UTC timestamps and per-hop delays.
Read headers without opening a message
Paste raw headers, not an HTML email body. Folded continuation lines are unfolded; original field order and duplicates remain in the report. From, To, Cc, Reply-To, Sender and Return-Path are also parsed as mailbox lists when possible. The first blank line ends the header block; anything after it is ignored.
MIME encoded words using B/Base64 or Q encoding can be decoded with the browser’s supported character sets. Unsupported or malformed encoded words remain visible with a diagnostic. Decoding a display name does not make an address or sender trustworthy.
Understand the Received timeline
Mail servers normally prepend Received fields, so the report reverses their header order to show earlier hops first. Supported numeric time-zone offsets are converted to UTC, and adjacent parseable timestamps produce a delay in seconds. Negative delays remain visible: clock skew, forged fields or unusual routing can produce them.
Numeric offsets, UT and GMT are supported. Unknown zone abbreviations and invalid dates return null, rather than relying on your machine’s local time zone. This does not verify SPF, DKIM, DMARC, IP reputation or certificate trust. A sender can forge header fields outside a trusted receiving system. Limits are 200,000 characters, 1,000 fields and a cancellable 10-second task.
Reference
Questions & answers
Can this prove who sent an email?
No. It helps inspect the text and timing. Authentication requires the original message, signatures, DNS records and a trusted receiving context.
Why are some Received timestamps null?
The field may lack a supported timestamp, use an ambiguous time-zone abbreviation or contain an impossible date. The raw field is preserved for manual review.
Is my input uploaded?
No. Parsing and generation run in your browser. Engines and datasets load from this site; the tool does not store input or send it to a processing API.