MIME

MIME stands for "Multipurpose Internet Mail Extensions," which is an Internet standard that extends the format of email messages. It is primarily utilized by web browsers and email clients to send and receive messages with audio, images, video, and text in character sets other than ASCII.

Why was the MIME standard created?

The standard was defined by the Internet Engineering Task Force (IETF) in June 1992 as a way for messages sent over the Internet to support data beyond just ASCII text. This includes the ability to attach files, such as spreadsheets, videos, images, audio, and documents to email messages. Email messages that utilize MIME formatting are normally transmitted with the Simple Mail Transfer Protocol (SMTP), Internet Message Access Protocol (IMAP), and Post Office Protocol (POP) protocols.

The MIME standard is used in contexts other than email transmission. Web servers insert the MIME header at the start of web transmissions, and clients and applications utilize MIME types to identify the media type of files to handle them better.

What is a MIME type?

The MIME type is a standard that indicates the type of data stored in a file or some collection of bytes. Regarding messages, a MIME header is inserted into a message that identifies the MIME version and media type of the message content.

A simple MIME type consists of type/subtype. The type is the general category of data, whereas the subtype is the specific kind of data. For example, a message with a video saved in the Ogg container format would have the video/ogg MIME type.

Also, there are two possible variations of type:

• Discrete - Represents a single file, such as a spreadsheet file or image file. Examples of discrete types include application, audio, image, and video.
• Multipart - Represents a composite document comprised of multiple parts, with each part possibly having their own MIME type. This typically occurs when a user attaches multiple files to an email. There are two multipart types: message and multipart.

Over the years, various specifications have been released to extend MIME capabilities. Some extensions include data that outlines the message content's structure and specifies when the content should be displayed in the message (automatically or require the user to open it manually).

MIME data types are registered with the Internet Assigned Numbers Authority (IANA), an organization under the Internet Architecture Board (IAB). Some common MIME types