What is Markdown? The .md Plain-Text Format Explained

Markdown is a lightweight plain-text markup language created by John Gruber in 2004 that converts to HTML. Learn how Markdown works, its syntax, and uses.

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What is Markdown? The .md Plain-Text Format Explained

A lightweight plain-text markup language that converts easily to HTML.

Last updated:

Year Created2004
CompressionLightweight markup
Primary UseDocs, READMEs, notes

What is MARKDOWN?

Markdown is a lightweight markup language created by John Gruber in 2004, with input from Aaron Swartz, designed to be easy to read and write as plain text. Its goal is to let people format text using simple, unobtrusive punctuation that can be converted to structurally valid HTML.

A Markdown document is just plain text with conventions: hash marks for headings, asterisks or underscores for emphasis, hyphens for lists, and brackets for links. A processor converts these cues into HTML (or other formats). The IETF registered the text/markdown media type in RFC 7763 (2016), and the CommonMark project provides a precise, widely adopted specification.

How Markdown Works

Markdown is processed by a parser that scans the plain text for formatting cues and emits structured HTML; Gruber's original design explicitly allowed raw HTML to be interspersed for anything the syntax does not cover.[4] The emphasis on readability means a Markdown source remains legible even before conversion.[4]

History and Standardization

John Gruber released Markdown in 2004 with input from Aaron Swartz, accompanied by a reference Perl implementation rather than a formal grammar.[2] The IETF later registered the text/markdown media type in RFC 7763, and the CommonMark project produced a precise specification to resolve ambiguities between implementations.[1]

Variants and Limitations

Because the original specification left edge cases undefined, numerous incompatible dialects emerged, and popular extensions such as GitHub Flavored Markdown add tables, task lists, and fenced code blocks beyond the base syntax.[2] CommonMark addresses interoperability by defining exact parsing rules.[3]

MKV Technical Specifications

DeveloperJohn Gruber (with Aaron Swartz)[1]
File Extension.md, .markdown[1]
MIME Typetext/markdown[1]
Released2004 (media type registered 2016)[1]
TypeLightweight plain-text markup language[1]

MARKDOWN vs Other Document Formats

FeatureMarkdownHTMLTXTRTF
Structure/typePlain-text markup[2]Tag markupPlain textTagged text
Human-readable sourceYes[4]PartlyYesNo
FormattingLightweightRichNoneRich
Standardized byIETF / CommonMark[3]WHATWGNoneMicrosoft
Media typetext/markdown[1]text/htmltext/plainapplication/rtf
Best forReadable formatted textWeb pagesRaw notesPortable rich text

Markdown keeps source human-readable with light formatting, while HTML offers richer structure at the cost of verbosity.

Advantages & Disadvantages

Advantages

Human-readable | FileFormer

Markdown source is easy to read and write even before conversion, unlike HTML or XML markup.

Portable plain text | FileFormer

Files are plain text, so they work in any editor and play well with version control systems like Git.

Converts to many formats | FileFormer

Markdown can be rendered to HTML and, via tools like Pandoc, to PDF, DOCX, and more.

Widely adopted | FileFormer

It is the default for READMEs, documentation, and many writing and note-taking platforms.

Disadvantages

Syntax fragmentation | FileFormer

Many flavors (CommonMark, GitHub Flavored Markdown, and others) differ in features, causing inconsistencies.

Limited native features | FileFormer

Core Markdown lacks tables, footnotes, and complex layout, which require extensions or raw HTML.

Not a layout language | FileFormer

Markdown describes structure, not precise visual layout, so it is unsuitable for pixel-level design.

Common Use Cases

Markdown is used wherever lightweight, readable text formatting is valuable.

Software documentation | FileFormer

READMEs, wikis, and docs on platforms like GitHub and GitLab are typically written in Markdown.

Notes and writing | FileFormer

Note-taking and writing apps use Markdown so authors can format text quickly with plain keystrokes.

Static site content | FileFormer

Static site generators convert Markdown source files into HTML pages for blogs and websites.

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Frequently Asked Questions

Who created Markdown?

Markdown was created in 2004 by John Gruber, with feedback from Aaron Swartz. Gruber wrote the original specification and reference implementation.

What is the difference between .md and .markdown?

They are the same format; .md is the common short extension and .markdown is the longer alternative, both registered for the text/markdown media type.

What is CommonMark?

CommonMark is a standardized, unambiguous specification and test suite for Markdown, created to resolve inconsistencies between different Markdown implementations.

Can Markdown be converted to HTML?

Yes. Markdown was designed to convert into valid HTML, and processors can also export it to formats such as PDF and DOCX.

Is Markdown an official standard?

The text/markdown media type was registered by the IETF in RFC 7763 (2016), and CommonMark provides a precise community specification, though no single 'official' syntax governs all flavors.

References

  1. RFC 7763: The text/markdown Media Type - IETF
  2. Markdown - Wikipedia
  3. CommonMark Specification
  4. Daring Fireball: Markdown - John Gruber