streamich/json-joy

json-joy is a library that implements cutting-edge real-time and collaborative editing algorithms and utilities for JSON data models, with a focus on developing the JSON CRDT (Conflict-free Replicated Data Type) specification and implementation.

TypeScript

1,096

6,358 commits

updated Sep 8, 2026

See the code

README

json-joy

npm version

json-joy library implements cutting-edge real-time and collaborative editing algorithms and other utilities for JSON data models. Major focus of json-joy is development of the JSON CRDT protocol, a Conflict-free Replicated Data Type that enables seamless merging of changes in JSON data models, avoiding conflicts between replicas.

Notable features

  • Full JSON implementation as a CRDT (Conflict-free Replicated Datatype).
  • The fastest list CRDT implementation in JavaScript.
  • The fastest text OT (Operational Transformation) implementation in JavaScript.
  • The fastest implementation of CBOR, DAG-CBOR, MessagePack, UBJSON, and JSON codecs in JavaScript.
  • The fastest (HTTP) router implementation in JavaScript.
  • The fastest JSON schema validation implementation in JavaScript.
  • Very fast binary tree (Radix, AVL, Red-black*, Splay) implementations in JavaScript.
  • Very fast JSON Patch (and JSON Pointer) implementation in JavaScript, including many non-standard operations, and JSON Predicate implementation.
  • Very fast JSON Expression implementation in JavaScript.
cbor
collaboration
collaborative
collaborative-editing
crdt
json
json-crdt-patch
json-random
local-first
messagepack
multiplayer
offline
operational-transformation
p2p
patch
reactive
realtime
rpc
schema
ubjson

streamich/json-joy

json-joy is a library that implements cutting-edge real-time and collaborative editing algorithms and utilities for JSON data models, with a focus on developing the JSON CRDT (Conflict-free Replicated Data Type) specification and implementation.

TypeScript

1,096

6,358 commits

updated Sep 8, 2026

See the code

README

json-joy

npm version

json-joy library implements cutting-edge real-time and collaborative editing algorithms and other utilities for JSON data models. Major focus of json-joy is development of the JSON CRDT protocol, a Conflict-free Replicated Data Type that enables seamless merging of changes in JSON data models, avoiding conflicts between replicas.

Notable features

  • Full JSON implementation as a CRDT (Conflict-free Replicated Datatype).
  • The fastest list CRDT implementation in JavaScript.
  • The fastest text OT (Operational Transformation) implementation in JavaScript.
  • The fastest implementation of CBOR, DAG-CBOR, MessagePack, UBJSON, and JSON codecs in JavaScript.
  • The fastest (HTTP) router implementation in JavaScript.
  • The fastest JSON schema validation implementation in JavaScript.
  • Very fast binary tree (Radix, AVL, Red-black*, Splay) implementations in JavaScript.
  • Very fast JSON Patch (and JSON Pointer) implementation in JavaScript, including many non-standard operations, and JSON Predicate implementation.
  • Very fast JSON Expression implementation in JavaScript.
cbor
collaboration
collaborative
collaborative-editing
crdt
json
json-crdt-patch
json-random
local-first
messagepack
multiplayer
offline
operational-transformation
p2p
patch
reactive
realtime
rpc
schema
ubjson

Project health

Overall

4.2/10

Maintained

10/10

Code review

0/10
OpenSSF Scorecard

Latest release

18.30.0 · Sep 8, 2026

Releases this year

37

Significant stargazers

(top 24 of 29)

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5,087 followers · starred Aug 2025

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2,635 followers · starred Sep 2020

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