Novus Convert
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Data format

EML converter

An .eml file is a single saved email message: RFC 5322 headers, a blank line, then the body — which for anything modern is a MIME tree of alternative representations and attachments. It is what a mail client writes when you save or drag out a message.

Private for supported formats — processed in your browser

Convert supported files

Runs on your device

Drop EML files here

Batch files can each use a different output. Nothing uploads for local conversions.

Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.

Where EML comes from

The format is simply the on-the-wire message format of internet mail, first specified as RFC 822 in 1982 and revised as RFC 2822 and then RFC 5322. Outlook Express popularised saving individual messages with the .eml extension in the 1990s and the convention stuck. Because it is the wire format, an .eml file is exactly what traversed the internet, headers and all.

How EML works

  • Headers are name: value lines, folded across continuations with leading whitespace, terminated by one blank line.
  • MIME multipart bodies nest, with boundary strings declared in the Content-Type header of each part.
  • Non-ASCII header text is encoded per RFC 2047 as =?charset?encoding?text?= words.
  • Bodies are commonly base64 or quoted-printable encoded, so the raw file is not the readable message.
  • Received headers record the delivery path, which is why .eml is the format used for header analysis.

When to use EML

  • Archiving individual messages outside a mail account
  • Submitting a message for phishing or deliverability analysis, headers intact
  • Moving a message between mail clients
  • Extracting message text and metadata for review or disclosure

Strengths and limitations

Strengths

  • Byte-for-byte what was actually transmitted, including full headers
  • Universally readable by mail clients
  • Self-contained: attachments travel inside the file

Limitations

  • Not readable as-is — bodies are usually encoded
  • MIME nesting makes correct parsing considerably harder than it looks
  • Attachments make files far larger than the message they carry

Compatibility

Opened by Outlook, Thunderbird, Apple Mail and most desktop clients, and parsed by every mail library. Webmail generally will not import one directly. Novus Convert parses the message locally — decoding transfer encodings and walking the MIME tree — and converts to HTML, plain text and JSON.

Headers including sender, recipients, subject, date and message id are preserved, along with the text body. Attachments are not extracted into the text targets.

Convert EML to another format