File Format Encyclopedia

Your resource for file format specifications.

Wotsup.org is a community-driven archive providing hundreds of file format specifications, hardware notes, and implementation guides. Browse and contribute to help keep legacy data accessible.

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• 723+ file formats
• 21+ categories
• Community maintained

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What's inside

A comprehensive format reference library.

Formats documented

723

Detailed specifications, diagrams, and implementation tips.

Categories covered

21

From graphics and audio to printers, CAD, and communications.

Specs archived

1042+

Reference files, whitepapers, and utility documentation.

Explore the collection

Browse by format and category to find specs and decoding notes. For keyword searches, try a search engine with site:wotsup.org.

Explore the information architecture →

Engineering ready

Entries focus on structures, fields, and practical tips for building parsers.

Developer guidance →

Community powered

Submit corrections or new specs via GitHub. Every contribution is reviewed.

Contributing guide →

Get involved

Help expand the documentation.

Contribute format specifications, add implementation notes, or improve existing documentation. All contributions are welcome via GitHub.

• Submit specs via GitHub
• Add decoding tips
• Improve metadata + tagging

New to the archive?

Start with the quick guides.

Learn how to navigate the archive and find the format information you need.

How to use Wotsup.org Frequently asked questions Contact + support

Recent additions

Latest updates to the catalog.

1. Jul 17, 2026

   .nef updated Nikon NEF file format

   .ras updated Sun Rasterfile Format

   .ppm updated Portable Pixelmap format

   .xpm updated X PIxMap Format definition (Acrobat)

2. Jul 15, 2026

   .xbm updated X BitMap Format

   .psd updated Adobe Photoshop 2.5 File Format

3. Jul 14, 2026

   .ico updated Icon resources in ICO, DLL and EXE files (Also CUR files)

   .pcx updated PCX File Format Technical Reference

   .tga updated Targa image file format

   .djvu updated Complete DjVu specification (in DJVU so you need the plugin)

   .tex updated TeX, LaTeX, makeindx, Metafont formats

   .sgml updated Standard Generalized Markup Language (SGML)

   .xls updated Microsoft Excel File Format

   .ppt updated Microsoft Powerpoint 97 Format

   .doc updated Palm Pilot DOC files

4. Jul 13, 2026

   .rss updated Syndication file format

   .css updated Cascading Style Sheets 1

5. Jul 12, 2026

   .xml updated Extensible Markup Language (XML) 1.0

   .html updated HTML 2.0 (RFC 1866 approved by IETF)

   .csv updated Comma Separated Value Files

   .rtf updated Rich Text File Format v1.5 (MS Word)

Ready to contribute?

Every contribution helps keep file format knowledge accessible. Fork the repo, add your notes, and submit a pull request.

View the repository Contribution guide

Built on the foundation of Wotsit.org, originally created by Paul Oliver and contributors worldwide. Thanks to their pioneering work in documenting file formats. Read more about Wotsup.org →