Markdown was inspired by pre-existing conventions for marking up plain text in email and usenet posts, such as the earlier markup languages setext ({{Circa|1992}}), Textile (c. 2002), and reStructuredText (c. 2002).

In 2002 Aaron Swartz created atx and referred to it as "the true structured text format". Gruber created the Markdown language in 2004 with Swartz as his "sounding board".{{Cite tweet |user=gruber |number=741989829173510145 |title=I should write about it, but it's painful. More or less: Aaron was my sounding board, my muse.}} The goal of the language was to enable people "to write using an easy-to-read and easy-to-write plain text format, optionally convert it to structurally valid XHTML (or HTML)".Markdown 1.0.1 readme source code {{cite web|url=http://daringfireball.net/projects/markdown/ |title=Daring Fireball – Markdown |date=2004-12-17 |url-status=dead |archive-url=https://web.archive.org/web/20040402182332/http://daringfireball.net/projects/markdown/ |archive-date=2004-04-02 }}

Another key design goal was readability, that the language be readable as-is, without looking like it has been marked up with tags or formatting instructions,{{r|name="philosophy"|reference=Markdown Syntax {{cite web|url=http://daringfireball.net/projects/markdown/syntax#philosophy|title=Daring Fireball – Markdown – Syntax|date=2013-06-13 }} "Readability, however, is emphasized above all else. A Markdown-formatted document should be publishable as-is, as plain text, without looking like it's been marked up with tags or formatting instructions. While Markdown's syntax has been influenced by several existing text-to-HTML filters — including Setext, atx, Textile, reStructuredText, Grutatext{{r |name="grutatext" |reference={{Cite web |title=Un naufragio personal: The Grutatxt markup |url=https://triptico.com/docs/grutatxt_markup.html |access-date=2022-06-30 |website=triptico.com }} }}, and EtText{{r |name="ettext" |reference={{Cite web |title=EtText: Documentation: Using EtText |url=http://ettext.taint.org/doc/ettext.html |access-date=2022-06-30 |website=ettext.taint.org}} }} — the single biggest source of inspiration for Markdown's syntax is the format of plain text email." }} unlike text formatted with "heavier" markup languages, such as Rich Text Format (RTF), HTML, or even wikitext (each of which have obvious in-line tags and formatting instructions which can make the text more difficult for humans to read).

Gruber wrote a Perl script, {{code|Markdown.pl}}, which converts marked-up text input to valid, well-formed XHTML or HTML, encoding angle brackets ({{code|<}}, {{code|>}}) and ampersands ({{code|&}}), which would be misinterpreted as special characters in those languages. It can take the role of a standalone script, a plugin for Blosxom or a Movable Type, or of a text filter for BBEdit.

As Markdown's popularity grew rapidly, many Markdown implementations appeared, driven mostly by the need for additional features such as tables, footnotes, definition lists,Technically HTML description lists and Markdown inside HTML blocks.

The behavior of some of these diverged from the reference implementation, as Markdown was only characterised by an informal specification{{cite web|url=https://daringfireball.net/projects/markdown/syntax|title=Markdown Syntax Documentation|publisher=Daring Fireball|access-date=2018-03-09|archive-date=2019-09-09|archive-url=https://web.archive.org/web/20190909051956/https://daringfireball.net/projects/markdown/syntax|url-status=live}} and a Perl implementation for conversion to HTML.

At the same time, a number of ambiguities in the informal specification had attracted attention.{{cite web|url=https://github.github.com/gfm/#why-is-a-spec-needed-|title=GitHub Flavored Markdown Spec – Why is a spec needed?|website=github.github.com|access-date=2018-05-17|archive-date=2020-02-03|archive-url=https://web.archive.org/web/20200203204734/https://github.github.com/gfm/#why-is-a-spec-needed-|url-status=live}} These issues spurred the creation of tools such as Babelmark{{cite web |url=http://johnmacfarlane.net/babelmark2/ |title=Babelmark 2 – Compare markdown implementations |publisher=Johnmacfarlane.net |access-date=2014-04-25 |archive-date=2017-07-18 |archive-url=https://web.archive.org/web/20170718113552/http://johnmacfarlane.net/babelmark2/ |url-status=live }}{{cite web |url=https://babelmark.github.io/ |title=Babelmark 3 – Compare Markdown Implementations |publisher=github.io |access-date=2017-12-10 |archive-date=2020-11-12 |archive-url=https://web.archive.org/web/20201112043521/https://babelmark.github.io/ |url-status=live }} to compare the output of various implementations,{{cite web |url=http://johnmacfarlane.net/babelmark2/faq.html |title=Babelmark 2 – FAQ |publisher=Johnmacfarlane.net |access-date=2014-04-25 |archive-date=2017-07-28 |archive-url=https://web.archive.org/web/20170728115918/http://johnmacfarlane.net/babelmark2/faq.html |url-status=live }} and an effort by some developers of Markdown parsers for standardisation. However, Gruber has argued that complete standardization would be a mistake: "Different sites (and people) have different needs. No one syntax would make all happy."{{cite tweet|user=gruber|author-link=John Gruber|first=John|last=Gruber|number=507670720886091776|date=4 September 2014|title=@tobie @espadrine @comex @wycats Because different sites (and people) have different needs. No one syntax would make all happy.}}

Gruber avoided using curly braces in Markdown to unofficially reserve them for implementation-specific extensions.{{cite web |url=https://daringfireball.net/linked/2022/05/19/markdoc |title=Markdoc |last=Gruber |first=John |date=19 May 2022 |website=Daring Fireball |access-date=May 19, 2022 |quote=I love their syntax extensions — very true to the spirit of Markdown. They use curly braces for their extensions; I'm not sure I ever made this clear, publicly, but I avoided using curly braces in Markdown itself — even though they are very tempting characters — to unofficially reserve them for implementation-specific extensions. Markdoc's extensive use of curly braces for its syntax is exactly the sort of thing I was thinking about. |archive-date=19 May 2022 |archive-url=https://web.archive.org/web/20220519202920/https://daringfireball.net/linked/2022/05/19/markdoc |url-status=live }}

{{Infobox file format

| name = CommonMark

| logo = Markdown-mark.svg{{!}}class=skin-invert

| icon_size = 175px

| _noextcode = on

| extensions = .md, .markdown

| _nomimecode = on

| mime = text/markdown; variant=CommonMark

| uniform type = uncertain{{cite web|url= https://talk.commonmark.org/t/uti-of-a-commonmark-document/2406|title= UTI of a CommonMark document|date= 12 April 2017|access-date= 29 September 2017|archive-date= 22 November 2018|archive-url= https://web.archive.org/web/20181122140119/https://talk.commonmark.org/t/uti-of-a-commonmark-document/2406|url-status= live}}

| conforms to = public.plain-text

| owner = John MacFarlane, open source

| released = {{start date and age|2014|10|25|paren=yes}}

| latest release version = 0.31.2

| latest release date = {{start date and age|2024|01|28|paren=yes}}{{cite web |url= http://spec.commonmark.org/ |title= CommonMark specification |access-date= 2017-07-26 |archive-date= 2017-08-07 |archive-url= https://web.archive.org/web/20170807052756/http://spec.commonmark.org/ |url-status= live }}

| genre = Markup language

| extended from = Markdown

| extended to = GitHub Flavored Markdown

| type = Open file format

| url = {{URL|https://commonmark.org/}}

{{URL|http://spec.commonmark.org/}}

}}

From 2012, a group of people, including Jeff Atwood and John MacFarlane, launched what Atwood characterised as a standardisation effort.{{cite web |last=Atwood |first=Jeff |url=http://www.codinghorror.com/blog/2012/10/the-future-of-markdown.html |title=The Future of Markdown |publisher=CodingHorror.com |date=2012-10-25 |access-date=2014-04-25 |archive-date=2014-02-11 |archive-url=https://web.archive.org/web/20140211233513/http://www.codinghorror.com/blog/2012/10/the-future-of-markdown.html |url-status=dead }}

A community website now aims to "document various tools and resources available to document authors and developers, as well as implementors of the various Markdown implementations".{{cite web |url=https://markdown.github.io/ |title=Markdown Community Page |publisher=GitHub |access-date=2014-04-25 |archive-date=2020-10-26 |archive-url=https://web.archive.org/web/20201026161924/http://markdown.github.io/ |url-status=live }}

In September 2014, Gruber objected to the usage of "Markdown" in the name of this effort and it was rebranded as CommonMark.{{cite web |url=http://blog.codinghorror.com/standard-markdown-is-now-common-markdown/ |title=Standard Markdown is now Common Markdown |date=4 September 2014 |publisher=Jeff Atwood |access-date=2014-10-07 |archive-date=2014-10-09 |archive-url=https://web.archive.org/web/20141009181014/http://blog.codinghorror.com/standard-markdown-is-now-common-markdown/ |url-status=live }}{{cite web |url=http://www.infoq.com/news/2014/09/markdown-commonmark |title=Standard Markdown Becomes Common Markdown then CommonMark |work=InfoQ |access-date=2014-10-07 |archive-date=2020-09-30 |archive-url=https://web.archive.org/web/20200930150521/https://www.infoq.com/news/2014/09/markdown-commonmark/ |url-status=live }} CommonMark.org published several versions of a specification, reference implementation, test suite, and "[plans] to announce a finalized 1.0 spec and test suite in 2019".{{cite web |url=http://commonmark.org/ |title=CommonMark |language=en |access-date=20 Jun 2018 |quote=The current version of the CommonMark spec is complete, and quite robust after a year of public feedback … but not quite final. With your help, we plan to announce a finalized 1.0 spec and test suite in 2019. |archive-date=12 April 2016 |archive-url=https://web.archive.org/web/20160412211434/http://commonmark.org/ |url-status=live}}

No 1.0 spec has since been released, as major issues still remain unsolved.{{Cite web |date=2015-07-26 |title=Issues we MUST resolve before 1.0 release [6 remaining] |url=https://talk.commonmark.org/t/issues-we-must-resolve-before-1-0-release-6-remaining/1287 |access-date=2020-10-02 |website=CommonMark Discussion |language=en-US |archive-date=2021-04-14 |archive-url=https://web.archive.org/web/20210414032229/https://talk.commonmark.org/t/issues-we-must-resolve-before-1-0-release-6-remaining/1287 |url-status=live}}

Nonetheless, the following websites and projects have adopted CommonMark: Discourse, GitHub, GitLab, Reddit, Qt, Stack Exchange (Stack Overflow), and Swift.

In March 2016, two relevant informational Internet RFCs were published:

• {{IETF RFC|7763|link=no}} introduced MIME type {{code|text/markdown}}.
• {{IETF RFC|7764|link=no}} discussed and registered the variants MultiMarkdown, GitHub Flavored Markdown (GFM), Pandoc, and Markdown Extra among others.{{cite web |url=https://www.iana.org/assignments/markdown-variants/markdown-variants.xhtml |title=Markdown Variants |publisher=IANA |date=2016-03-28 |access-date=2016-07-06 |archive-date=2020-10-27 |archive-url=https://web.archive.org/web/20201027005128/https://www.iana.org/assignments/markdown-variants/markdown-variants.xhtml |url-status=live}}

Websites like Bitbucket, Diaspora, Discord,{{Cite web |date=2024-10-03 |title=Markdown Text 101 (Chat Formatting: Bold, Italic, Underline) |url=https://support.discord.com/hc/en-us/articles/210298617-Markdown-Text-101-Chat-Formatting-Bold-Italic-Underline |access-date=2025-02-07 |website=Discord |language=en-US}} GitHub,{{cite web|title=GitHub Flavored Markdown Spec|url=https://github.github.com/gfm/|access-date=2020-06-11|publisher=GitHub|archive-date=2020-02-03|archive-url=https://web.archive.org/web/20200203204734/https://github.github.com/gfm/|url-status=live}} OpenStreetMap, Reddit,{{cite web|title=Reddit markdown primer. Or, how do you do all that fancy formatting in your comments, anyway?|url=https://www.reddit.com/r/reddit.com/comments/6ewgt/reddit_markdown_primer_or_how_do_you_do_all_that/|access-date=2013-03-29|publisher=Reddit|archive-date=2019-06-11|archive-url=https://web.archive.org/web/20190611185827/https://www.reddit.com/r/reddit.com/comments/6ewgt/reddit_markdown_primer_or_how_do_you_do_all_that/|url-status=live}} SourceForge{{cite web|title=SourceForge: Markdown Syntax Guide|url=http://sourceforge.net/p/forge/documentation/markdown_syntax/|access-date=2013-05-10|publisher=SourceForge|archive-date=2019-06-13|archive-url=https://web.archive.org/web/20190613130356/https://sourceforge.net/p/forge/documentation/markdown_syntax/|url-status=live}} and Stack Exchange{{cite web|title=Markdown Editing Help|url=https://stackoverflow.com/editing-help|access-date=2014-04-11|publisher=StackOverflow.com|archive-date=2014-03-28|archive-url=https://web.archive.org/web/20140328061854/http://stackoverflow.com/editing-help|url-status=live}} use variants of Markdown to make discussions between users easier.

Depending on implementation, basic inline HTML tags may be supported.{{cite web |title=Markdown Syntax Documentation |url=https://daringfireball.net/projects/markdown/syntax#html |website=daringfireball.net |access-date=2021-03-01 |archive-date=2019-09-09 |archive-url=https://web.archive.org/web/20190909051956/https://daringfireball.net/projects/markdown/syntax#html |url-status=live }}

Italic text may be implemented by _underscores_ or *single-asterisks*.{{cite web | url=https://www.markdownguide.org/basic-syntax/#italic | title=Basic Syntax: Italic | publisher=Matt Cone | work=The Markdown Guide | accessdate=27 March 2022 | quote=To italicize text, add one asterisk or underscore before and after a word or phrase. To italicize the middle of a word for emphasis, add one asterisk without spaces around the letters. | archive-date=26 March 2022 | archive-url=https://web.archive.org/web/20220326234942/https://www.markdownguide.org/basic-syntax/#italic | url-status=live }}

GitHub had been using its own variant of Markdown since as early as 2009,{{cite web |title = GitHub Flavored Markdown Examples |author = Tom Preston-Werner |url = https://github.com/mojombo/github-flavored-markdown/issues/1 |website = GitHub |accessdate = 2021-04-02 |archive-date = 2021-05-13 |archive-url = https://web.archive.org/web/20210513154115/https://github.com/mojombo/github-flavored-markdown/issues/1 |url-status = live }} which added support for additional formatting such as tables and nesting block content inside list elements, as well as GitHub-specific features such as auto-linking references to commits, issues, usernames, etc.

In 2017, GitHub released a formal specification of its GitHub Flavored Markdown (GFM) that is based on CommonMark. It is a strict superset of CommonMark, following its specification exactly except for tables, strikethrough, autolinks and task lists, which GFM adds as extensions.{{Cite web |url = https://githubengineering.com/a-formal-spec-for-github-markdown/ |title = A formal spec for GitHub Flavored Markdown |website = GitHub Engineering |date = 14 March 2017 |access-date = 16 Mar 2017 |archive-date = 3 February 2020 |archive-url = https://web.archive.org/web/20200203205138/https://githubengineering.com/a-formal-spec-for-github-markdown/ |url-status = live }}

Accordingly, GitHub also changed the parser used on their sites, which required that some documents be changed. For instance, GFM now requires that the hash symbol that creates a heading be separated from the heading text by a space character.

Markdown Extra is a lightweight markup language based on Markdown implemented in PHP (originally), Python and Ruby.{{cite web

| last1 = Fortin

| first1 = Michel

| title = PHP Markdown Extra

| date = 2018

| work = Michel Fortin website

| url = https://michelf.ca/projects/php-markdown/extra

| access-date = 2018-12-26

| archive-date = 2021-01-17

| archive-url = https://web.archive.org/web/20210117015819/https://michelf.ca/projects/php-markdown/extra/

| url-status = live

}} It adds the following features that are not available with regular Markdown:

• Markdown markup inside HTML blocks
• Elements with id/class attribute
• "Fenced code blocks" that span multiple lines of code
• Tables{{cite web|url=https://michelf.ca/projects/php-markdown/extra|title=PHP Markdown Extra|website=Michel Fortin|access-date=2018-12-26|archive-date=2021-01-17|archive-url=https://web.archive.org/web/20210117015819/https://michelf.ca/projects/php-markdown/extra/|url-status=live}}
• Definition lists
• Footnotes
• Abbreviations

Markdown Extra is supported in some content management systems such as Drupal,{{cite web|url=https://drupal.org/project/markdowneditor|title=Markdown editor for BUEditor|date=4 December 2008|access-date=15 January 2017|archive-date=17 September 2020|archive-url=https://web.archive.org/web/20200917172201/https://www.drupal.org/project/markdowneditor|url-status=live}} Grav (CMS) and TYPO3.{{cite web|url=https://extensions.typo3.org/extension/markdown_content/|title=Markdown for TYPO3 (markdown_content)|website=extensions.typo3.org|access-date=2019-02-06|archive-date=2021-02-01|archive-url=https://web.archive.org/web/20210201205749/https://extensions.typo3.org/extension/markdown_content/|url-status=live}}

{|class="wikitable"

! width="33%" | Text using Markdown syntax

! width="34%" | Corresponding HTML produced by a Markdown processor

! width="33%" | Text viewed in a browser

|-valign="top"

|

Heading

Sub-heading

-----------

1. Alternative heading

1. Alternative sub-heading

Paragraphs are separated

by a blank line.

Two spaces at the end of a line

produce a line break.

|

Heading

Sub-heading

Alternative heading

Alternative sub-heading

Paragraphs are separated

by a blank line.

Two spaces at the end of a line

produce a line break.

|

Paragraphs are separated

by a blank line.

Two spaces at the end of a line

produce a line break.

|-

|Text attributes _italic_, **bold**, `monospace`.

Horizontal rule:

---

|

Text attributes italic, bold, monospace.

Horizontal rule:

|Text attributes italic, bold, monospace.

Horizontal rule:

|-

|

Bullet lists nested within numbered list:

1. fruits

* apple

* banana

2. vegetables

- carrot

- broccoli

|

Bullet lists nested within numbered list:

1. fruits

   • apple
   • banana

2. vegetables

   • carrot
   • broccoli

|Bullet lists nested within numbered list:

1. fruits
2. * apple
3. * banana
4. vegetables
5. * carrot
6. * broccoli

|-

|A [link](http://example.com).


> Markdown uses email-style

characters for blockquoting.

>

> Multiple paragraphs need to be prepended individually.

Most inline HTML tags are supported.

|

A link.

{{blockquote|

Markdown uses email-style characters for blockquoting.

Multiple paragraphs need to be prepended individually.

}}

Most inline HTML tags are supported.

|A [http://example.com/ link].

File:Icon-pictures.png

{{blockquote|

Markdown uses email-style characters for blockquoting.

Multiple paragraphs need to be prepended individually.

}}

Most inline HTML tags are supported.

|}

Implementations of Markdown are available for over a dozen programming languages; in addition, many applications, platforms and frameworks support Markdown.{{cite web|title=W3C Community Page of Markdown Implementations|url=https://www.w3.org/community/markdown/wiki/MarkdownImplementations|website=W3C Markdown Wiki|access-date=24 March 2016|archive-date=17 September 2020|archive-url=https://web.archive.org/web/20200917231621/https://www.w3.org/community/markdown/wiki/MarkdownImplementations|url-status=live}} For example, Markdown plugins exist for every major blogging platform.

While Markdown is a minimal markup language and is read and edited with a normal text editor, there are specially designed editors that preview the files with styles, which are available for all major platforms. Many general-purpose text and code editors have syntax highlighting plugins for Markdown built into them or available as optional download. Editors may feature a side-by-side preview window or render the code directly in a WYSIWYG fashion.

• Comparison of document markup languages
• Comparison of documentation generators
• Lightweight markup language
• Wiki markup

{{Reflist|group=note}}

{{Reflist|30em|refs=

{{cite news |last=Gilbertson |date=October 5, 2014 |first=Scott |title=Markdown throwdown: What happens when FOSS software gets corporate backing? |url=https://arstechnica.com/information-technology/2014/10/markdown-throwdown-what-happens-when-foss-software-gets-corporate-backing/ |work=Ars Technica |access-date=June 14, 2017 |archive-date=November 14, 2020 |archive-url=https://web.archive.org/web/20201114231130/https://arstechnica.com/information-technology/2014/10/markdown-throwdown-what-happens-when-foss-software-gets-corporate-backing/ |url-status=live |quote=CommonMark fork could end up better for users... but original creators seem to disagree.}}

}}

• {{Official website|https://daringfireball.net/projects/markdown/}} for original John Gruber markup

{{Document markup languages}}

{{Authority control|state=autocollapse}}

Category:Computer-related introductions in 2004

Category:Lightweight markup languages

Category:Open formats