ooxml.dev is an interactive reference for ECMA-376 (Office Open XML) — the standard behind .docx, .xlsx, and .pptx files. Built by the SuperDoc team, who implemented a native OOXML renderer from scratch. Features: live previews (edit XML, see it render in real-time using SuperDoc's native OOXML engine), implementation notes (documents real-world behavior where Microsoft Word diverges from the spec), semantic spec search (18,000+ spec chunks searchable by meaning via MCP server at api.ooxml.dev/mcp), and practical guides for paragraphs, tables, borders, bidirectional text, and document creation. The OOXML spec is 5,000+ pages of PDFs with no rendering guidance — this site bridges that gap with knowledge from people who actually implemented the spec. Covers WordprocessingML (the .docx subset). SuperDoc is open source at superdoc.dev. Built by Caio Pizzol (caiopizzol.com), Head of DX at SuperDoc.
w:p

Paragraphs

Text structure and formatting in OOXML - paragraphs, runs, and text elements.

Paragraphs (w:p) are the fundamental building block of WordprocessingML. They contain runs (w:r), which contain text (w:t).

Structure

w:p (paragraph)
├── w:pPr (paragraph properties)
│   ├── w:pStyle (style reference)
│   ├── w:jc (justification)
│   └── w:spacing (line spacing)
└── w:r (run)
    ├── w:rPr (run properties)
    │   ├── w:b (bold)
    │   ├── w:i (italic)
    │   └── w:sz (font size)
    └── w:t (text)

Example

<w:p>
  <w:pPr>
    <w:jc w:val="center"/>
  </w:pPr>
  <w:r>
    <w:t xml:space="preserve">Normal text, </w:t>
  </w:r>
  <w:r>
    <w:rPr><w:b/></w:rPr>
    <w:t>bold text</w:t>
  </w:r>
  <w:r>
    <w:t xml:space="preserve">, and </w:t>
  </w:r>
  <w:r>
    <w:rPr><w:i/></w:rPr>
    <w:t>italic text</w:t>
  </w:r>
</w:p>

Implementation Notes

Whitespace handling (All)

By default, leading/trailing whitespace in w:t is trimmed. Use xml:space="preserve" to keep spaces.

Empty paragraphs

Empty paragraphs are valid and commonly used for spacing. They render as a blank line with the paragraph's line height.