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Email Header Parser

Parse raw email headers into structured key-value pairs. Handles RFC 2822 folded headers, RFC 2047 encoded words, multi-value headers, and DKIM/SPF authentication headers. Filter by header name, decode encoded subjects, and export as JSON. Runs entirely in your browser — your data never leaves your machine.

email headers parser smtp rfc2822 dkim spf mime

Published May 31, 2026

All interactive tools run entirely in your browser. Your data never leaves your device.

How It Works

Paste raw email headers and see them parsed into structured name-value pairs. The parser handles RFC 2822 folded (continuation) lines, RFC 2047 encoded words in subjects and other fields, and multiple headers with the same name (like Received chains).

Features

  • RFC 2822 compliant: correctly unfolds continuation lines (tab/space indented)
  • RFC 2047 decoding: decodes Base64 and Quoted-Printable encoded words in headers
  • Filter by name: narrow results to a specific header type (Received, From, etc.)
  • Multi-value support: handles multiple headers with the same name (common for Received)
  • Copy individual values: click to copy any header value
  • Export as JSON: copy all parsed headers as a JSON array
  • 5 preset examples: basic email, multi-value, DKIM/SPF, encoded subject, mailing list
  • Private: all processing runs in your browser — no data transmitted

Use Cases

  • Debugging email delivery issues by examining Received chains
  • Verifying DKIM signatures and SPF authentication results
  • Inspecting MIME structure and Content-Type parameters
  • Decoding encoded email subjects for readability
  • Analyzing mailing list headers (List-Id, List-Unsubscribe)