DOCX file format
Microsoft Word Document (Office Open XML)
DOCX is Microsoft Word's default format since 2007: a ZIP archive of XML files describing text, styles, tables and images. It's editable but can look different on other devices — PDF is better for final copies.
| Property | DOCX |
|---|---|
| File extensions | .docx |
| MIME type | application/vnd.openxmlformats-officedocument.wordprocessingml.document |
| Introduced | 2007 by Microsoft (ISO/IEC 29500) |
| Type | Editable word-processing document |
| How it's stored | ZIP of XML files |
| Keeps formatting | Yes — styles, tables, images |
| Compatibility | Word, Google Docs, LibreOffice, Pages |
| Best for | Writing and editing documents |
What is a DOCX file?
DOCX is the Office Open XML word-processing format introduced with Word 2007 and standardised as ISO/IEC 29500 in 2008. Rename a .docx to .zip and you'll find folders of XML files for the text, styles and settings, plus a media folder for images.
Strengths and weaknesses
DOCX is the most widely used editable document format and opens in Word, Google Docs, LibreOffice and Apple Pages. But layout depends on the fonts and software used to open it, so pages can reflow — which is why forms and applications usually ask for PDF.
Converting DOCX in the browser
Fylo reads DOCX with the open-source mammoth library, which extracts text, headings, lists, tables and images reliably. Complex layouts — text boxes, columns, headers and footers — can't be reproduced exactly without Word itself, so check the result for important documents.