Protocol Buffers - Google's data interchange format

FASTJSON 2.0.x has been released, faster and more secure, recommend you upgrade.

FlatBuffers: Memory Efficient Serialization Library

Cross-browser storage for all use cases, used across the web.

A high-performance 100% compatible drop-in replacement of "encoding/json"

Protocol Buffers for JavaScript & TypeScript.

A proof-of-concept tool for generating payloads that exploit unsafe Java object deserialization.

A lightweight library for converting complex objects to and from simple Python datatypes.

Fast, correct Python JSON library supporting dataclasses, datetimes, and numpy

Java binary serialization and cloning: fast, efficient, automatic

Extremely Fast MessagePack Serializer for C#(.NET, .NET Core, Unity, Xamarin). / msgpack.org[C#]

Kotlin multiplatform / multi-format serialization

Static reflection for enums (to string, from string, iteration) for modern C++, work with any enum type without any macro or boilerplate code

A C++11 library for serialization

A handy swift json-object serialization/deserialization library

🚄 FASTJSON2 is a Java JSON library with excellent performance.

HTML parsing/serialization toolset for Node.js. WHATWG HTML Living Standard (aka HTML5)-compliant.

Rusty Object Notation

C++ Reflection Library

The fastest JSON library in C