An In-Browser Viewer for Office Open XML Documents

OOXML Viewer is a high-performance, open-source JavaScript library designed to render Office files directly within the browser using a powerful combination of Rust, WebAssembly (WASM), and the Canvas 2D API.

@silurus/ooxml provides a comprehensive solution for displaying .docx, .xlsx, and .pptx files without relying on external dependencies.

🛠️ Technical Architecture

Unlike traditional viewers, this library eliminates the need for ~~server-side document conversion~~, native software installations, or the use of iframes. Everything happens on the client side.

The rendering process can be conceptually represented as: $\text{Document} \xrightarrow{\text{Rust/WASM}} \text{Canvas Instructions} \rightarrow \text{Visual Output}$

Core Pillars:

Rust/WASM Parsers: The heavy lifting of parsing .docx, .xlsx, and .pptx is handled by Rust and compiled to WASM for near-native speed.
Canvas Rendering: Visuals are drawn using the Canvas 2D interface for optimal browser performance.
Standard-Compliant: The engine is built based on the $\text{ECMA-376}$ and $\text{ISO 29500}$ specifications, alongside official Microsoft documentation.
Flexible Integration: Developers can use the pre-built viewers or leverage the Document APIs to create custom thumbnails, navigation systems, or previews.

🚀 Getting Started

To integrate the library into your project, use the following command:

npm install @silurus/ooxml

Quick Capabilities Checklist:

Switch between different file formats
Navigate through pages or slides
Scroll through expansive spreadsheets
Zoom and search within documents

📊 Format Support Matrix

While complex documents may still exhibit slight differences compared to the native Microsoft Office suite, the library supports a vast array of features.

Feature	`.docx` (Word)	`.xlsx` (Excel)	`.pptx` (PowerPoint)
Layout	Paginated, headers, footers, sections	Multi-sheet, frozen panes, outlines	Slide masters & layout inheritance
Tables/Data	Complex borders, fills, merged cells	Cached formulas, dates, number formats	Table text selection
Visuals	Inline/anchored images, DrawingML	Classic charts, sparklines, conditional formatting	Preset/custom shapes, SmartArt, 3D shading
Advanced	CJK typography (ruby, vertical writing)	Pivot metadata, CJK cell text	WordArt, embedded fonts, audio/video
Specialty	Math equations, tracked changes	TSV copy, internal links	Classic combo & stock charts
Rendering	Progressive virtualized scroll	Range/element context	Progressive virtualized scroll
Images	Optional TIFF decoding	Optional TIFF decoding	Optional TIFF decoding

📢 Latest Announcements

Stay updated with the most recent release and migration notes.

Version History

v0.84.1 (Sep 1, 2026):
- Word Layout Improvements: Refined spacing for legacy text-boxes.
- Stability: Page-break behavior is now more strictly aligned with original Word document designs.
v0.84.0 (Sep 1, 2026):
- TIFF Support: Introduced an opt-in feature to display TIFF images across all three supported formats.
- Note: This is enabled by default in the VS Code extension.
v0.83.0 (Aug 28, 2026):
- Performance: Large .docx and .pptx files now load initial pages/slides faster.
- Optimization: Increased speed for large Word tables.
- Fonts: Now utilizes embedded PowerPoint fonts when available.

For more details, visit the GitHub Repository or check the full support matrix in the README.