Open-source alternatives to Json Joy

Loro is a conflict-free replicated data type (CRDT) framework and collaborative state engine designed for building real-time collaborative applications. It provides a distributed data synchronizer that enables multiple users to edit shared documents and complex nested structures—such as maps, lists, trees, and counters—with automatic state convergence without requiring a central server. The project distinguishes itself through a versioned document store that supports branching, forking, and merging via a directed acyclic graph of causal operation history. It enables advanced version control c

This project is a reactive, offline-first NoSQL database engine designed for JavaScript applications. It provides a robust framework for managing application state by synchronizing data across browsers, mobile devices, and server-side runtimes. By treating local storage as the primary source of truth, it enables applications to remain functional without network connectivity, automatically reconciling changes with remote backends once a connection is restored. The database distinguishes itself through a modular architecture that supports cross-environment synchronization and high-performance d

This project is a memory-safe library implemented in Rust that provides a high-performance engine for managing shared, distributed data states. It functions as a conflict-free replicated data type implementation, enabling real-time collaborative editing and state synchronization across distributed systems without the need for a central server or manual conflict resolution. The library distinguishes itself through a cross-language binding framework that allows native applications in environments like Python, Swift, and WebAssembly to interact with the same shared data protocol. It utilizes a c

xi-editor is a high-performance text editor core written in Rust. It employs a client-server architecture that separates the backend editor logic from the user interface, allowing diverse frontends to communicate with the core via a standardized protocol. The project is distinguished by its use of rope-based text buffers for efficient manipulation of large documents and a collaborative engine powered by conflict-free replicated data types to synchronize concurrent edits. It further features an extensible plugin system that integrates external binaries and third-party tools through JSON-based

Yjs is a CRDT framework and real-time state synchronization engine providing shared data types for collaborative software. It functions as a shared data type library of collaborative maps, arrays, and text structures that converge automatically across distributed clients, serving as a local-first data store and a collaborative editor backend. The system distinguishes itself through a synchronization engine that encodes document changes into commutative binary updates. It employs state-vector based differencing to transmit only missing incremental updates between peers and uses relative-positi

CodeMirror is a browser-based code editor framework and modular extension system used to embed full-featured text editors into web pages. It functions as a syntax tree parsing engine and a language server protocol client, enabling structural language analysis and deep integration with external programming language services. The project is distinguished by its modular architecture, which uses a system of extensions and compartments for dynamic reconfiguration at runtime. It supports real-time collaborative editing and state synchronization through an operational transformation framework, allow

cr-sqlite is a multi-master database replication system that uses conflict-free replicated data types to ensure eventual consistency across distributed nodes. It provides the core capabilities for offline-first data synchronization, allowing multiple database instances to merge concurrent updates and reach a consistent state. The project distinguishes itself through a combination of CRDT-based data replication and a WASM-based database engine, enabling full SQL execution and state persistence within web browsers. It supports peer-to-peer replication and cross-tab synchronization, utilizing ca

Slate is a customizable rich text editor framework that treats documents as a recursive tree of nodes. It functions as a schema-based, state-driven system designed to enforce structural constraints and manage nested components within a structured document model. The framework utilizes a plugin-based architecture to extend editor functionality, allowing for the injection of custom logic into the rendering and transformation pipeline. It supports real-time collaborative editing by synchronizing document operations across multiple users. The system covers a broad range of capabilities, includin

Tiptap is a headless, modular framework designed for building custom rich-text editors. It provides a developer-focused abstraction layer over a structured document model, allowing for full control over the underlying schema through a plugin-based architecture. By separating document state management from the user interface, it enables the creation of tailored editing experiences that remain framework-agnostic. The project distinguishes itself through a robust collaborative engine that supports real-time multi-user editing, conflict resolution, and presence tracking. It integrates artificial

BlockNote is a block-based rich text editor and a real-time collaborative workspace. It uses a JSON-based data model to organize content into draggable, nestable blocks rather than a single flat document. The system functions as a high-level interface built on ProseMirror that abstracts document state into discrete, manipulatable content blocks. The project serves as a framework for integrating large language models into document editors, enabling context-aware text generation and AI-driven workflows. It also acts as a document export engine capable of converting structured block data into fo

FluidFramework is a real-time collaboration framework and distributed state synchronization engine. It provides a collaborative data model library and a cloud-synced document system designed to replicate data structures across connected clients using ordered operations to ensure eventual consistency. The framework utilizes a client-server relay architecture to route and persist operations without requiring custom server-side business logic. It manages the lifecycle of collaborative sessions through shared data containers and implements conflict resolution strategies, such as last-writer-wins,

This project is a plugin-based WYSIWYG document layout engine and rich text editor that uses Canvas and SVG for rendering. It functions as a collaborative editor utilizing conflict-free replicated data types to enable real-time synchronization across multiple users. The system serves as an interactive form builder, allowing for the embedding of input controls such as checkboxes and date pickers directly into documents. It is designed for high-fidelity output, ensuring the visual representation during editing matches the final format for PDF and image exports. The editor covers broad capabili

BlockSuite is a collaborative block editor framework built on a hierarchical block tree data model with CRDT-based state synchronization for real-time multi-user editing. It provides an extensible block component system, allowing developers to define custom block types through declarative schemas, services, and rendering components. The editor is packaged as cross-framework web components, making it embeddable in any JavaScript environment. The framework distinguishes itself with a command-driven editing pipeline that composes type-safe editing actions with dynamic context sharing and control

Yoopta-Editor is a headless framework for building customizable block-based rich text editors. It utilizes a JSON-based document engine to manage editor state and provides a WYSIWYG interface for creating structured documents. The system separates core document logic from the visual layer, allowing for complete customization of the user interface. The framework is designed for real-time collaborative editing, featuring a synchronization engine with conflict resolution and remote cursor presence tracking. It offers a highly extensible plugin system that allows developers to define new content

Automerge is a distributed state synchronization engine and library for conflict-free replicated data types. It enables multiple nodes to perform concurrent updates to a shared dataset while guaranteeing that all replicas eventually converge to the same state. The project provides a high-performance implementation written in Rust to manage state merging and synchronization. It employs a byte-compressed synchronization protocol to transmit minimal delta updates between peers, facilitating data consistency in peer-to-peer and real-time collaborative environments. The system covers broad capabi

PartyKit is a serverless WebSocket backend platform for building real-time multiplayer applications. It provides a globally distributed edge computing runtime that runs stateful server code close to users, with automatic scaling and hibernation for idle rooms. The platform handles WebSocket connections, HTTP requests, and durable storage without requiring infrastructure management, and includes a client and server SDK with hooks, storage, and Yjs integration for building collaborative features. The platform distinguishes itself through per-room isolation using Durable Objects, where each uniq

Wireflow is a real-time collaborative flowchart tool and visual mapping application. It provides a shared digital canvas where multiple users can simultaneously design diagrams, map user flows, and create process maps. The application uses an operational transformation engine to resolve conflicting edits and maintain a consistent state across all users. A vector-based renderer ensures that flowchart elements remain sharp at any zoom level, while a WebSocket synchronization layer broadcasts canvas updates and cursor movements instantly between clients. The project is delivered as a containeri

ONLYOFFICE DocumentServer is a self-hosted online office suite that provides browser-based document, spreadsheet, and presentation editing with real-time collaborative capabilities. It natively supports Office Open XML formats (.docx, .xlsx, .pptx) and can be deployed on Linux servers, either through Docker containerization or direct installation. The server includes a cooperative editing engine that coordinates simultaneous changes across multiple users using operational transformation, with a WebSocket synchronization layer for instant state propagation. Security is handled through JWT auth

Lexical is a modular rich text editor framework used to build extensible web-based editors. It functions as a state-driven content editor that maintains a serializable, immutable snapshot of document content to ensure predictable updates and accessibility compliance. The framework is distinguished by its plugin-based architecture and customizable node framework, which allow developers to extend editor behavior through specialized content nodes and encapsulated runtime logic. It also includes a collaborative editing engine capable of synchronizing document state across multiple clients in real

This project is a JavaScript spreadsheet component and web-based data table that provides an interactive grid for managing tabular data. It functions as a cross-framework UI component compatible with React, Vue, and jQuery, and can also be embedded as a standalone web component. The grid is specifically designed for XLSX interoperability, allowing users to import and export XLSX files while preserving formulas and styles. It distinguishes itself through real-time collaboration for simultaneous multi-user editing and a flexible system for creating custom cell editors and specialized column typ

JSBin is a collaborative JavaScript playground and online frontend sandbox for writing, executing, and debugging web code. It provides a real-time code editor and an integrated environment that instantly renders HTML, CSS, and JavaScript with a live preview. The platform is designed for live coding demonstrations and pair programming, featuring a broadcasting environment that transmits keystrokes and code changes to other users instantly. It supports real-time synchronization for multiple developers through shared live sessions and includes a transpilation tool to convert alternative programm

CodeMirror 5 is a browser-based code editor and extensible UI component. It functions as a syntax highlighting engine and a programmable text surface, providing a professional coding experience embedded within web pages. The project is distinguished by its ability to act as a collaborative text editor, synchronizing document changes across multiple users in real time. It also includes a dedicated Vim emulation layer that implements modal keyboard interactions, motions, and operators. The system covers broad capability areas including language support for autocompletion and error analysis, co

CKEditor 5 is a modular rich text editor framework and JavaScript UI component used to build customizable visual editors. It serves as a system for generating HTML or Markdown content, providing both full rich-text editor components and restricted inline editor components for web applications. The framework includes a collaborative editing engine for real-time simultaneous editing, change tracking, and threaded commenting. It features an AI text assistant for polishing, rewriting, and generating content, as well as a document export engine that transforms rich text into PDF and Word files. T

Rete is a framework for building interactive, node-based visual interfaces and dataflow programming environments. It provides a core engine that processes directed graphs, allowing developers to define modular logic where nodes represent operations and connections represent the flow of data or control. By decoupling the graph logic from the user interface, the framework enables the creation of custom visual editors that can be integrated into various frontend component libraries. The project distinguishes itself through a highly extensible, signal-driven architecture that supports complex req

TinyBase is a reactive data store and in-memory relational database designed for client-side state persistence. It serves as a local-first sync engine that merges distributed state using conflict-free replicated data types and logical clocks to ensure deterministic data convergence. The project features a schema validation library that converts external definitions from tools like Zod, Yup, and TypeBox into type-safe store definitions. It provides an infrastructure for real-time collaborative editing, utilizing synchronization with Automerge, Yjs, and PartyKit to maintain consistent state acr

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

This project is a comprehensive diagramming ecosystem that functions as both a standalone cross-platform desktop application and a modular JavaScript library for web-based mind mapping. It provides a visual workspace for structuring hierarchical information, allowing users to create, organize, and manipulate complex node trees through an interactive canvas interface. The platform distinguishes itself through deep integration with artificial intelligence, enabling users to automatically generate, expand, and refine diagram content directly within their workspace. It supports real-time collabor