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.

Start contributing How to use

• 722+ file formats
• 20+ categories
• Community maintained

Quick links

• How to use
• FAQ
• About

What's inside

A comprehensive format reference library.

Formats documented

722

Detailed specifications, diagrams, and implementation tips.

Categories covered

20

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

Specs archived

1036+

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. Nov 21, 2025

   Surveying file format added – view

   Roller Coaster Tycoon save ame (*.SV4), track (*.TD4), track picture (*.TP4), and scenario (*.SC4) file formats added – view

   Tracker Packer v1/v2/v3 formats added – view

   TWAIN 1.8 Specification (Acrobat) added – view

   Eudora Table of Contents added – view

   TeX, LaTeX, makeindx, Metafont formats added – view

   TMX - Translation Memory Exchange added – view

   Targa image file format added – view

   TTF free source project added – view

   Microsoft Windows NT 3.5/3.51/4.0 TCP/IP Implementation Details, TCP/IP Protocol Stack and Services, Version 2.0 added – view

   +712 more

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 →