# Jansson Documentation

This is the documentation for Jansson 2.15.1, last updated July 02, 2026.

## Introduction

Jansson is a C library for encoding, decoding and manipulating JSON data. Its main features and design principles are:

- Simple and intuitive API and data model

- Comprehensive documentation

- No dependencies on other libraries

- Full Unicode support (UTF-8)

- Extensive test suite

Jansson is licensed under the MIT license; see LICENSE in the source distribution for details.

Jansson is used in production and its API is stable. It works on numerous platforms, including numerous Unix like systems and Windows. It’s suitable for use on any system, including desktop, server, and small embedded systems.

## Contents

- Getting Started
  - Compiling and Installing Jansson
  - Compiling Programs that Use Jansson
- Upgrading from 1.x
  - Compatibility
  - List of Incompatible Changes
- Tutorial
  - The GitHub Repo Commits API
  - The Program
  - Conclusion
- RFC Conformance
  - Character Encoding
  - Strings
  - Numbers
  - Depth of nested values
- Thread safety
  - Hash function seed
  - Memory allocation functions
  - Locale
- API Reference
  - Preliminaries
  - Library Version
  - Value Representation
  - True, False and Null
  - String
  - Number
  - Array
  - Object
  - Error reporting
  - Encoding
  - Decoding
  - Building Values
  - Parsing and Validating Values
  - Equality
  - Copying
  - Custom Memory Allocation
  - Fixed-Length keys
- Changes in Jansson
  - Version 2.15.1
  - Version 2.15.0
  - Version 2.14.1
  - Version 2.14
  - Version 2.13.1
  - Version 2.13
  - Version 2.12
  - Version 2.11
  - Version 2.10
  - Version 2.9
  - Version 2.8
  - Version 2.7
  - Version 2.6
  - Version 2.5
  - Version 2.4
  - Version 2.3.1
  - Version 2.3
  - Version 2.2.1
  - Version 2.2
  - Version 2.1
  - Version 2.0.1
  - Version 2.0
  - Version 1.3
  - Version 1.2.1
  - Version 1.2
  - Version 1.1.3
  - Version 1.1.2
  - Version 1.1.1
  - Version 1.1
  - Version 1.0.4
  - Version 1.0.3
  - Version 1.0.2
  - Version 1.0.1
  - Version 1.0

# Indices and Tables

- Index

- Search Page