kaitai-io/kaitai_struct

Kaitai Struct: declarative language to generate binary data parsers in C++ / C# / Go / Java / JavaScript / Lua / Nim / Perl / PHP / Python / Ruby / Rust

Shell

4,700

1,049 commits

updated Oct 11, 2026

See the code

README

Kaitai Struct

Join the chat at https://gitter.im/kaitai_struct/Lobby

[!NOTE] If you want to make changes to the project, do not fork this kaitai_struct repository. Instead, choose the component you want to modify in the file tree above and fork that individual component instead.

This is an umbrella repository, containing the components only as submodules to make it easier to check out the entire project. Unless you want to modify this README, it is not the repo where you can make edits.

What is Kaitai Struct?

Kaitai Struct (KS) is a declarative language used to describe various binary data structures, laid out in files or in memory: i.e. binary file formats, network stream packet formats, etc.

The main idea is that a particular format is described in Kaitai Struct language (.ksy file) only once and then can be compiled with kaitai-struct-compiler (or ksc for short) into source files in one of the supported programming languages. These modules will include generated code for a parser that can read the described data structure from a file or stream and provide access to it in a nice, easy-to-comprehend API.

What is it used for?

Have you ever found yourself writing repetitive, error-prone and hard-to-debug code that reads binary data structures from file / network stream and somehow represents them in memory for easier access?

Kaitai Struct tries to make this job easier — you only have to describe the binary format once and then everybody can use it from their programming languages — cross-language, cross-platform.

Kaitai Struct includes a growing collection of format descriptions, available in formats submodule repository.

Using KS in your project

Typically, using formats described in KS in your project involves the following steps:

  • Describe the format — i.e. create a .ksy file
  • Use a visualizer to debug the format and ensure that it parses data properly (official visualizers are Web IDE and the console visualizer ksv)
  • Compile the .ksy file into a target language source file and include that file in your project
  • Add the KS runtime library for your particular language to your project (don't worry, it's small and it's there mostly to ensure readability of generated code)
  • Use the generated class(es) to parse your binary file or stream and access its components

To see an example, a list of supported languages, download instructions and licensing information, visit https://kaitai.io/.

c-plus-plus
cpp
csharp
declarative-language
file-format
go
golang
graphviz
java
javascript
lua
nim
perl
php
protocol-analyser
python
reverse-engineering
ruby
rust

kaitai-io/kaitai_struct

Kaitai Struct: declarative language to generate binary data parsers in C++ / C# / Go / Java / JavaScript / Lua / Nim / Perl / PHP / Python / Ruby / Rust

Shell

4,700

1,049 commits

updated Oct 11, 2026

See the code

README

Kaitai Struct

Join the chat at https://gitter.im/kaitai_struct/Lobby

[!NOTE] If you want to make changes to the project, do not fork this kaitai_struct repository. Instead, choose the component you want to modify in the file tree above and fork that individual component instead.

This is an umbrella repository, containing the components only as submodules to make it easier to check out the entire project. Unless you want to modify this README, it is not the repo where you can make edits.

What is Kaitai Struct?

Kaitai Struct (KS) is a declarative language used to describe various binary data structures, laid out in files or in memory: i.e. binary file formats, network stream packet formats, etc.

The main idea is that a particular format is described in Kaitai Struct language (.ksy file) only once and then can be compiled with kaitai-struct-compiler (or ksc for short) into source files in one of the supported programming languages. These modules will include generated code for a parser that can read the described data structure from a file or stream and provide access to it in a nice, easy-to-comprehend API.

What is it used for?

Have you ever found yourself writing repetitive, error-prone and hard-to-debug code that reads binary data structures from file / network stream and somehow represents them in memory for easier access?

Kaitai Struct tries to make this job easier — you only have to describe the binary format once and then everybody can use it from their programming languages — cross-language, cross-platform.

Kaitai Struct includes a growing collection of format descriptions, available in formats submodule repository.

Using KS in your project

Typically, using formats described in KS in your project involves the following steps:

  • Describe the format — i.e. create a .ksy file
  • Use a visualizer to debug the format and ensure that it parses data properly (official visualizers are Web IDE and the console visualizer ksv)
  • Compile the .ksy file into a target language source file and include that file in your project
  • Add the KS runtime library for your particular language to your project (don't worry, it's small and it's there mostly to ensure readability of generated code)
  • Use the generated class(es) to parse your binary file or stream and access its components

To see an example, a list of supported languages, download instructions and licensing information, visit https://kaitai.io/.

c-plus-plus
cpp
csharp
declarative-language
file-format
go
golang
graphviz
java
javascript
lua
nim
perl
php
protocol-analyser
python
reverse-engineering
ruby
rust

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