automerge
A CRDT for JSON-like data structures. Implementations in JavaScript and rust.
Also has an efficient binary storage format.
Used in production with Washington Post for their internal collaboration tools. Quite mature as far as these things go.
Martin Kleppmann is one of the core developers.
Maybe automerge and JSON-LD are a perfect fit? We get the best of both worlds? Semantic, Linked Data and the ease of JSON?
A CRDT and linked data (with belonging schemas)?
JSON-LD also supports translations and tagging of them in the data structure. Internationalisation with JSON-LD (i18n)
Can we use something like ShEx (Shape Expressions) to build schemas and validation even if we use JSON instead of turtle? See Turtle is a format for expressing RDF data.
Make an automerge browser, like the firebase interface, with folding tree structure. Can we display the whole datastore, and have it update in real time? See automerge explorer, Hypermedia browser.
See also formats.