Message body
Everything in an email after the header and the blank line that ends it: the text, HTML and attachments, structured by MIME when there is more than plain text.
What it means
In RFC 5322 the body is simply the lines of text after the header section. MIME gives it structure: a Content-Type header says what the body is, and a multipart body holds several parts separated by boundary lines, each with its own small header, for example a plain-text version, an HTML version and attachments.
Content filters read the body: its links and the domains they point to, hidden text (which Google warns against), and attachments and their types. DKIM covers it through a body hash in the signature's bh= tag, so any change after signing, such as a footer added by a relay or a re-encoding, makes DKIM fail. Size matters too: Gmail clips long HTML bodies.
Related terms
Sources
What this definition rests on. The wording is ours; the facts are theirs.
- RFC 5322, section 2.3: Bodyrfc-editor.org
- RFC 2045: Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodiesrfc-editor.org
- RFC 6376, section 3.5: The DKIM-Signature Header Fieldrfc-editor.org
- Google, Gmail Help: Email sender guidelinessupport.google.com
All 432 terms in the glossaryThe wiki: blocklists and bounce codes