Content-Transfer-Encoding: base64 - Base64 Encoded Content

Email Tutorials - Herong's Tutorial Examples

∟Content-Transfer-Encoding: base64 - Base64 Encoded Content

This section provides an email message example with 'Content-Transfer-Encoding: base64' header to indicate that the content is Base64 encoded, commonly used for protecting non-ASCII characters.

What Is "Content-Transfer-Encoding: base64" Email Header? "Content-Transfer-Encoding: base64" specifies that the email message content is Base64 encoded. The email client tool needs to decode it to obtain the original content.

Here is a simple example of email message with the same content as the one in the previous tutorial. But it is delivered as a Base64 encoded content.

Message-Id: <20231113111946.5EABD266002B@mail.herongyang.com>
Date: 15 Nov 2023 06:19:34 -0500 (EST)
From: joe@herongyang.com
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: base64

5L2g5aW977yBIC0gSGVsbG8h

The main advantage of using "Content-Transfer-Encoding: base64" is that the encoded content contains 7-bit characters only, and it is much safer to be transmitted between SMTP servers.