Open-source alternatives to Json Iterator Go

Ultrajson is a high-performance Python JSON library and C-based parser designed to minimize parsing overhead. It provides a C implementation of the JSON specification to enable fast encoding and decoding of data. The project functions as a concurrent JSON processor, supporting multi-threaded serialization and deserialization to increase data throughput and prevent blocking execution. Its capabilities cover Python data serialization and high-performance JSON processing for real-time data pipelines. This includes parsing JSON data and serializing native objects into JSON strings.

orjson is a high-performance Python library for serializing and deserializing JSON data. It functions as both a JSON parsing library and a serialization engine, converting data between native Python objects and UTF-8 encoded bytes. The project provides specialized support for converting complex Python data structures, including dataclasses, datetime objects, and NumPy arrays and scalars, into JSON format. It also allows for the insertion of pre-serialized JSON blobs into documents to maintain processing speed. The library includes capabilities for memory-efficient deserialization through key

Fastjson is a Java data binding framework and serialization library designed to convert objects to JSON strings and parse JSON data into typed objects. It functions as a JSON parser and stream processor capable of transforming JSON strings into data structures. The project emphasizes high performance JSON processing and memory management, specifically through the use of a pipeline to stream oversized JSON objects and texts to prevent memory exhaustion. It provides capabilities for JSON data serialization and deserialization workflows, including custom JSON data mapping and the ability to def

UltraJSON is a high-performance JSON library and parser written in C with bindings for Python. It provides a fast alternative to standard JSON processing for decoding JSON strings into native data structures and encoding data structures back into JSON strings. The library utilizes a C-based engine to reduce processing latency and increase throughput for JSON generation and parsing. It is designed to accelerate data pipelines and optimize the handling of JSON payloads.

easyjson is a high-performance JSON serializer and memory-optimized parser for Go. It provides a reflectionless code generator that creates static Go methods for marshaling and unmarshaling data, eliminating the need for runtime reflection to improve execution speed. The library reduces CPU and memory overhead through several optimization strategies. It employs a system of reusable memory buffer pools to minimize heap allocations and garbage collection pressure. Additionally, it utilizes string interning to deduplicate repeated values and zero-copy string referencing to point to existing buff

yyjson is a high-performance C library for parsing, serializing, and manipulating JSON data structures. It functions as a memory-efficient data tool that utilizes custom memory pools and contiguous block allocation to minimize fragmentation and overhead. The project distinguishes itself as a SIMD JSON processor, using hardware-accelerated vector instructions for rapid string validation and parsing. It provides a toolkit for querying, modifying, and patching nested JSON objects and arrays through pointer-based access and path expressions. The library covers a broad range of data manipulation

Moshi is a JSON serialization library and parser for Kotlin and Java. It functions as a reflectionless JSON encoder that converts typed objects to JSON strings and parses JSON data back into language objects. The library distinguishes itself through compile-time adapter generation, which removes the performance overhead associated with runtime reflection. It also provides a polymorphic JSON mapper that uses type identifiers to resolve and instantiate specific subclasses of a common base type. The framework supports custom adapter definitions for specialized type conversion, including nullabi

Gson is a Java library designed for the serialization and deserialization of objects into structured text formats. It functions as a reflection-based data mapper, inspecting class structures at runtime to automatically convert memory-resident objects into data representations and reconstruct them back into typed language objects. The library distinguishes itself through a modular type-adapter pattern that allows for custom conversion rules for complex or nested structures. It also provides robust support for production environments by generating build-time metadata and configuration rules, wh

This project is a Protocol Buffers implementation for Go, providing a binary serialization framework to convert native data structures into a compact binary format for efficient network transmission and storage. It functions as a language bindings generator, utilizing a compiler plugin to create Go source code from platform-neutral protocol buffer definitions. The implementation includes a JSON data mapper that transforms structured binary messages into JSON format to facilitate compatibility with web services and external APIs. It also enables cross-language data exchange by using a common s

Jackson is a Java data binding framework and multi-format data serializer used to translate data structures into native language objects. It functions as a JSON data binding library and a streaming parser that reads and writes data as discrete tokens to process large datasets with minimal memory. The project distinguishes itself through a bytecode serialization accelerator that replaces standard reflection with generated bytecode to increase data binding speed. It employs a module-based extensibility model to support a wide range of formats beyond JSON, including XML, YAML, CSV, TOML, and bin

FlatBuffers is a cross-platform serialization library designed for performance-critical applications that require efficient, zero-copy data access. By organizing data in a structured binary format, it allows applications to read and write complex data structures directly from memory-mapped buffers without the need for intermediate parsing or temporary object allocation. The project distinguishes itself through a schema-driven approach that balances high-performance access with long-term data evolution. It utilizes a unique memory layout featuring relative offsets and inline fixed-size structu

This is a JavaScript library for parsing and serializing JSON data, with a particular focus on handling objects that contain circular references. It provides a standard JSON parser that reads text and reconstructs JavaScript values without using the eval function, guarding against code injection, alongside a standard serializer that converts objects into JSON strings for data interchange. The library distinguishes itself by offering specialized encoding and decoding for cyclical object graphs. It can serialize objects with circular references by replacing repeated object paths with JSONPath s

CloudEvents is an open specification for describing event data in a common format across cloud platforms and services. It defines a standard structure and set of metadata attributes for events, enabling interoperability across different systems so producers and consumers can exchange events without custom translation. The specification provides a protocol-agnostic serialization framework that maps CloudEvents attributes and payloads to multiple serialization formats including JSON, Avro, and Protobuf, and defines transport bindings for mapping events onto protocols like HTTP, AMQP, Kafka, MQTT

Superjson is a lossless JSON serialization library and data transcoder. It converts complex JavaScript and TypeScript data types into strings and metadata to ensure that type identity is preserved during data transfer. The library preserves non-native types such as Dates, Maps, and Sets by splitting values into a JSON-compatible payload and a separate map of type-specific metadata. It utilizes a registry-based mapping system that allows for the definition of custom type handlers to manage third-party data types during serialization and deserialization. This utility supports cross-process dat

simdjson is a high-performance JSON parser that utilizes SIMD instructions to process gigabytes of data per second. It functions as a SIMD JSON parser, a multithreaded NDJSON processing library, a UTF-8 validation engine, and a tool for JSON minification and string building. The project focuses on high-throughput data processing, enabling the ingestion of massive JSON volumes and the verification of UTF-8 encoding standards. It includes dedicated capabilities for constructing JSON strings with optimized memory usage and removing unnecessary whitespace from documents to reduce file size. The

Dataclasses-json is a library designed to facilitate the bidirectional conversion between Python data classes and JSON formats. It serves as a serialization tool that populates structured objects from raw data and transforms object instances into JSON strings, utilizing Python type hints to automate the mapping process. The library distinguishes itself by providing mechanisms for schema validation and runtime type coercion, ensuring that incoming data adheres to predefined model structures. It supports complex data requirements through recursive object traversal, which allows for the processi

RapidJSON is a header-only C++ library designed for high-performance parsing, generation, and manipulation of JSON data. It functions as a dual-mode engine, providing both an in-memory document object model for tree-based manipulation and a stream-based interface for event-driven processing. The library is built to minimize memory footprint and maximize execution speed, making it suitable for resource-constrained environments. The library distinguishes itself through advanced memory management and optimization techniques, including in-situ parsing that modifies input buffers directly to elimi

node-fs-extra is a Node.js file system extension that provides a set of additional methods to simplify common file and directory operations. It functions as a recursive directory manager, a JSON file processor, and a file asset manipulator, extending the standard library to provide high-level utilities for managing assets on disk. The project distinguishes itself through recursive capabilities, such as duplicating or removing nested folder structures and ensuring that all missing parent directories are automatically generated when creating files or symbolic links. It also integrates a JSON se

go-json is a high-performance JSON serialization library for Go that serves as an encoder and decoder replacement for the standard library. It provides tools to convert native data structures to and from JSON format with optimized processing speeds. The library includes a conditional serializer for filtering specific data structure fields during the encoding process and a colorizer to produce color-coded JSON strings for human readability. The project supports context-aware marshaling to trigger specific logic during the serialization of complex data types.

Sonic is a high-performance Go JSON serialization library that provides tools for encoding and decoding native data structures. It functions as a JIT-accelerated encoder, a JSON AST parser, a stream processor, and a lazy decoder. The project utilizes just-in-time machine code generation to optimize the encoding of large data schemas and employs a JIT assembler to maximize serialization and deserialization speeds. It features a precompiled schema warmup process to prevent latency spikes during initial execution and leverages SIMD hardware instructions for accelerated parsing. The library cove

JSONKit is an Objective-C library used for parsing, serializing, and manipulating JSON data. It functions as a JSON parser that converts text into native data structures and a serializer that transforms native objects into formatted JSON text. The library includes a gzip compression wrapper that compresses serialized JSON payloads to reduce network transfer sizes and automatically detects and decompresses gzip buffers before decoding. The toolset provides capabilities for JSON parsing and serialization, supporting customizable indentation, character escaping, and flexible comment handling.

fastjson2 is a high-performance Java library used for serializing and deserializing Java objects to and from JSON strings and byte arrays. It functions as a binary JSON serializer for encoding objects into optimized binary formats to reduce payload size and increase processing speed. The project includes a JSONPath query engine for extracting specific data and fields from JSON documents using standardized path expressions and filters. It also serves as a JSON schema validator, providing utilities to generate data contracts and validate JSON input against defined schemas to ensure structural c

This project is a framework for the efficient serialization and deserialization of data structures. It provides a unified, macro-based interface that automates the conversion of complex internal objects into standardized formats and reconstructs them from raw input streams or buffers. By leveraging compile-time code generation, the library minimizes manual implementation overhead while ensuring consistent logic across diverse data types. The framework distinguishes itself through a format-agnostic data model and a visitor-based parsing architecture that decouples data structures from specific

Newtonsoft.Json is a data processing utility for the .NET ecosystem designed to facilitate the transformation and exchange of information. It functions as a serialization library and object mapping framework, enabling the conversion of complex application objects into formatted JSON strings and the reconstruction of structured objects from raw JSON data. The library distinguishes itself through a flexible architecture that supports both strongly-typed class mapping and a dynamic object model for schema-less data manipulation. It employs reflection-based metadata mapping to automate property a

Sprig is a comprehensive library of helper functions designed to extend the Go text template engine. It provides a wide array of custom functions that can be injected into the engine to enable complex data manipulation and logic directly within templates. The project offers specialized capabilities for cryptography, including the generation of private keys, X.509 certificates, and secure password hashes. It also includes advanced logic extensions for semantic versioning comparison, ternary evaluations, and the resolution of environment variables from the host operating system. The library co

RestSharp is a .NET HTTP client library designed for interacting with RESTful web services. It provides a high-level request wrapper and a dedicated REST API client to manage endpoints, headers, and query parameters. The library includes a serialization mechanism that automatically converts objects to and from JSON or XML formats for API payloads. It also features a system for managing API credentials and security tokens to ensure authorized access to protected remote resources. The toolkit covers broad capabilities for external web service integration, including generic type-based deseriali

SwiftyJSON is a Swift JSON parsing library and data wrapper designed to simplify the reading and manipulation of JSON structures. It provides a toolkit for converting raw JSON strings into structured formats without requiring manual type casting or optional chaining for every value. The library focuses on simplifying nested data extraction through subscript-based value access and recursive data resolution. It ensures optional-safe value retrieval by returning default empty values instead of crashing when encountering missing keys or out-of-bounds array indices. The project includes capabilit