EPUB

AsciiDoc is a lightweight text-based markup language designed for authoring technical documentation, books, articles, and presentations in plain text files. It provides a richer feature set than Markdown, including built-in support for tables, cross-references, document includes, and complex layouts. AsciiDoc is widely used by technical publishers and open-source projects, and can be converted to HTML, PDF, EPUB, and DocBook.

DOCX is the default file format for Microsoft Word documents since Office 2007, built on the Open XML standard developed by Microsoft and standardized by ISO. It stores document content, formatting, images, tables, and metadata in a compressed ZIP archive containing XML files. DOCX is the dominant word processing format worldwide, supported by Microsoft Word, Google Docs, LibreOffice, and virtually all modern office software.

HTML (HyperText Markup Language) is the standard markup language for creating web pages and web applications, maintained by the W3C. It defines the structure and content of documents using elements and tags, working alongside CSS for visual styling and JavaScript for interactivity. HTML is rendered by web browsers into the visual pages users see, and is the universal output format for documents published on the internet.

Jupyter Notebook (IPYNB) is an interactive document format used by the Jupyter project for combining executable code, narrative text, visualizations, equations, and rich media in a single document. It is the standard tool in data science, machine learning research, and scientific computing for creating reproducible analyses and communicating results. IPYNB files store cells of code and Markdown in a JSON structure that can be run cell-by-cell in a live kernel.

Markdown is a lightweight plain-text markup language created by John Gruber in 2004 to make writing formatted content for the web as easy as possible. It uses minimal punctuation-based syntax to define headings, emphasis, links, images, lists, and code blocks that convert cleanly to HTML. Markdown is the dominant format for README files, software documentation, technical blogs, and static site generators across the entire software industry.

Emacs Muse is a markup language and authoring system built into the GNU Emacs text editor for creating structured documents, journals, and websites from plain text. It supports hierarchical outlines, internal and external links, tables, and multiple export formats including HTML and PDF. Muse is primarily used by Emacs power users who prefer to write all content, notes, and documents within their editing environment.

ODT (OpenDocument Text) is an open standard document format developed by OASIS for word processing, used as the native format by LibreOffice Writer and Apache OpenOffice Writer. It stores document content, styles, images, and metadata as XML in a ZIP archive, ensuring full transparency and long-term accessibility without vendor lock-in. ODT is also supported for import and export by Microsoft Word and Google Docs.

OPML (Outline Processor Markup Language) is an XML-based format designed for exchanging hierarchical outline and list structures between applications. It is most commonly used to export and import RSS/Atom feed subscription lists between news readers and podcast apps. OPML also serves as a portable format for structured notes, project outlines, and hierarchically organized content in productivity tools.

Org-mode is a plain-text format used within GNU Emacs for organizing notes, managing tasks and projects, writing documents, and creating structured content. It supports rich headings, nested lists, tables, source code blocks, links, and a complete task-management system with priorities, deadlines, and agenda views. Org files can be exported directly to HTML, PDF, LaTeX, ODT, and other formats from within Emacs.

PDF (Portable Document Format) was created by Adobe in 1992 and has become the worldwide standard for sharing documents with precisely fixed layouts. It preserves fonts, images, vector graphics, and formatting identically across every operating system, device, and printer. PDF supports digital signatures, encryption, interactive forms, and embedded multimedia, making it essential for official documents, contracts, reports, and professional publications.

reStructuredText (RST) is a plain-text markup language widely used for technical documentation in the Python programming ecosystem. It is the default documentation format for Python projects and the native input format for the Sphinx documentation generator, which produces HTML, PDF, ePub, and man pages. RST supports complex cross-references, footnotes, directives, and extensions, making it well-suited for large, structured documentation projects.

RTF (Rich Text Format) is a document interchange format developed by Microsoft in 1987 to allow formatted text to be shared across different word processors and operating systems. It encodes text formatting such as fonts, colors, bold, italic, and paragraph alignment using ASCII escape sequences, making it readable by virtually any word processor. RTF remains widely used as a compatibility format when the recipient's software is unknown.

TeX is a sophisticated typesetting system created by Donald Knuth for producing publication-quality documents, especially those containing complex mathematical notation. LaTeX, built as a macro layer on top of TeX, provides high-level document structuring commands and is the standard authoring format for academic papers in mathematics, physics, computer science, and engineering. TeX/LaTeX documents produce typographically precise output that surpasses word processors.

Textile is a lightweight markup language originally developed for the Textile CMS and later adopted by the Ruby on Rails community and various blogging platforms. It offers a simple, readable syntax for headings, emphasis, links, lists, tables, and code blocks that converts to clean HTML. While less widespread than Markdown today, Textile is still used in content management systems and project management tools like Redmine.

TXT (Plain Text) is the simplest possible file format, containing only unformatted characters encoded in ASCII or Unicode with no styling, images, or structural metadata. It is universally compatible with every operating system, programming language, text editor, and application that handles text. Plain text is used for source code, configuration files, README documents, log files, and any situation where maximum simplicity and portability are required.

AsciiDoc is a lightweight text-based markup language designed for authoring technical documentation, books, articles, and presentations in plain text files. It provides a richer feature set than Markdown, including built-in support for tables, cross-references, document includes, and complex layouts. AsciiDoc is widely used by technical publishers and open-source projects, and can be converted to HTML, PDF, EPUB, and DocBook.

DOC is the legacy binary file format used by Microsoft Word for the Office 97-2003 era. It stores document content, formatting, images, and metadata in a proprietary binary structure. Although superseded by the modern XML-based DOCX format, DOC remains common in older archives and is supported for import by virtually all modern word processors and office suites.

DOCX is the default file format for Microsoft Word documents since Office 2007, built on the Open XML standard developed by Microsoft and standardized by ISO. It stores document content, formatting, images, tables, and metadata in a compressed ZIP archive containing XML files. DOCX is the dominant word processing format worldwide, supported by Microsoft Word, Google Docs, LibreOffice, and virtually all modern office software.

HTML (HyperText Markup Language) is the standard markup language for creating web pages and web applications, maintained by the W3C. It defines the structure and content of documents using elements and tags, working alongside CSS for visual styling and JavaScript for interactivity. HTML is rendered by web browsers into the visual pages users see, and is the universal output format for documents published on the internet.

Jupyter Notebook (IPYNB) is an interactive document format used by the Jupyter project for combining executable code, narrative text, visualizations, equations, and rich media in a single document. It is the standard tool in data science, machine learning research, and scientific computing for creating reproducible analyses and communicating results. IPYNB files store cells of code and Markdown in a JSON structure that can be run cell-by-cell in a live kernel.

Markdown is a lightweight plain-text markup language created by John Gruber in 2004 to make writing formatted content for the web as easy as possible. It uses minimal punctuation-based syntax to define headings, emphasis, links, images, lists, and code blocks that convert cleanly to HTML. Markdown is the dominant format for README files, software documentation, technical blogs, and static site generators across the entire software industry.

Emacs Muse is a markup language and authoring system built into the GNU Emacs text editor for creating structured documents, journals, and websites from plain text. It supports hierarchical outlines, internal and external links, tables, and multiple export formats including HTML and PDF. Muse is primarily used by Emacs power users who prefer to write all content, notes, and documents within their editing environment.

ODT (OpenDocument Text) is an open standard document format developed by OASIS for word processing, used as the native format by LibreOffice Writer and Apache OpenOffice Writer. It stores document content, styles, images, and metadata as XML in a ZIP archive, ensuring full transparency and long-term accessibility without vendor lock-in. ODT is also supported for import and export by Microsoft Word and Google Docs.

OPML (Outline Processor Markup Language) is an XML-based format designed for exchanging hierarchical outline and list structures between applications. It is most commonly used to export and import RSS/Atom feed subscription lists between news readers and podcast apps. OPML also serves as a portable format for structured notes, project outlines, and hierarchically organized content in productivity tools.

Org-mode is a plain-text format used within GNU Emacs for organizing notes, managing tasks and projects, writing documents, and creating structured content. It supports rich headings, nested lists, tables, source code blocks, links, and a complete task-management system with priorities, deadlines, and agenda views. Org files can be exported directly to HTML, PDF, LaTeX, ODT, and other formats from within Emacs.

PDF (Portable Document Format) was created by Adobe in 1992 and has become the worldwide standard for sharing documents with precisely fixed layouts. It preserves fonts, images, vector graphics, and formatting identically across every operating system, device, and printer. PDF supports digital signatures, encryption, interactive forms, and embedded multimedia, making it essential for official documents, contracts, reports, and professional publications.

reStructuredText (RST) is a plain-text markup language widely used for technical documentation in the Python programming ecosystem. It is the default documentation format for Python projects and the native input format for the Sphinx documentation generator, which produces HTML, PDF, ePub, and man pages. RST supports complex cross-references, footnotes, directives, and extensions, making it well-suited for large, structured documentation projects.

RTF (Rich Text Format) is a document interchange format developed by Microsoft in 1987 to allow formatted text to be shared across different word processors and operating systems. It encodes text formatting such as fonts, colors, bold, italic, and paragraph alignment using ASCII escape sequences, making it readable by virtually any word processor. RTF remains widely used as a compatibility format when the recipient's software is unknown.

TeX is a sophisticated typesetting system created by Donald Knuth for producing publication-quality documents, especially those containing complex mathematical notation. LaTeX, built as a macro layer on top of TeX, provides high-level document structuring commands and is the standard authoring format for academic papers in mathematics, physics, computer science, and engineering. TeX/LaTeX documents produce typographically precise output that surpasses word processors.

Textile is a lightweight markup language originally developed for the Textile CMS and later adopted by the Ruby on Rails community and various blogging platforms. It offers a simple, readable syntax for headings, emphasis, links, lists, tables, and code blocks that converts to clean HTML. While less widespread than Markdown today, Textile is still used in content management systems and project management tools like Redmine.

TXT (Plain Text) is the simplest possible file format, containing only unformatted characters encoded in ASCII or Unicode with no styling, images, or structural metadata. It is universally compatible with every operating system, programming language, text editor, and application that handles text. Plain text is used for source code, configuration files, README documents, log files, and any situation where maximum simplicity and portability are required.

EML is a standardized file format for storing individual email messages, defined by the MIME standard (RFC 5322) and used by most email clients. It preserves the complete email including headers, plain-text body, HTML body, and file attachments exactly as they were transmitted. EML files are supported by Outlook, Thunderbird, Apple Mail, and are commonly used for email archiving, migration, and forensic analysis.

MSG is Microsoft Outlook's proprietary format for saving individual email messages, meeting requests, contacts, and tasks as standalone files. Unlike the standard EML format, MSG files use Microsoft's Compound Document File Format and require Outlook or a compatibility library to fully decode. MSG files preserve all rich formatting, embedded images, attachments, and complete email metadata, and are widely used in enterprise email archiving and legal discovery.