automerge VS y-crdt

I'm not aware of any usable CRDT implementations for Dart, my plan is to use the flutter_rust_bridge to make use of automerge v2, which is a full CRDT implementation written in Rust that has the advantage of having a very simple API to work with (basically a key/value store).

Yes. I asked the devs about ideas for this in this ticket and got an interesting response. It's aimed towards server-side handling, but the same ideas apply to local storage as well.

There are a lot of implementations of CRDTs out there. In JavaScript, for instance, we have Y.js (https://github.com/yjs/yjs) and automerge (https://github.com/automerge/automerge). There’s also a Y.js demo (https://demos.yjs.dev/prosemirror/prosemirror.html) that allows you to play around with them and have your own collaborative app running in just a few seconds. All messages are exchange via webRTC and manages the state via CRDTs. This can be a great sandbox to understand how CRDTs work and see.

Anyone unsure of what a CRDT is, this is the perfect intro: https://www.inkandswitch.com/peritext/

The two most widely used CRDT implementations (combining JSON like general purpose types and rich text editing types) are:

- Automerge https://github.com/automerge/automerge

- Yjs https://github.com/yjs/yjs

For instance, practicing "local first web" using automerge with all it's Distributed Persistence Primitives on CRDT's and Vector Clocks - i.e. when the Browser View is treated like a Database replica, essentially; or adopting a real data mapper that's giving you an API from your database Schema, using Prisma or Hasura... or even implementing a custom codegenereted one, as a babel plugin, on top of TSED and Micro-ORM.

Definitely agree that would be valuable. In fact our multiplayer state synchronization aspect is largely implemented in TypeScript (there's a TS element to the stack as well), and is built on top of YJS – there is a Rust implementation of YJS already though, which would likely be a great start for anyone looking to build something similar purely in Rust: https://github.com/y-crdt/y-crdt

We are working on a plugin API, which will allow people to build functionality that leverages the multiplayer data model – but within the app rather than as standalone applications.

It sounds like you want a Conflict-Free Replicated Data Type, CRDT for short. There are some Rust libraries you can use, but y-crdt seems very feature-complete, a port of Yjs.

I've found reliably persistence on the backend irritating with yjs. Seems like the official path is to fork their example library and edit it. (The example is insufficient because, for example, it will silently eat data if the onchange webhook fails).

yrs initially looks tempting but it's unsound at it's core. (The plan is to port the API directly from JS, use unsafe to silence the borrow checker, then gradually fix specific instances of undefined behavior if they cause actual real world issues.[1] I don't this this is an approach that can work. That's a shame because a lot of impressive work has gone into yrs.)

[1]: https://github.com/y-crdt/y-crdt/issues/233

So exciting! Strangely enough, a couple of hours before this release, we just managed to wrap our heads around Yjs after playing with it on and off for a few weeks!

For anyone not up to date with the world of CRDTs, Seph Gentle's two blog posts have become legendary:

* https://josephg.com/blog/crdts-are-the-future/

* https://josephg.com/blog/crdts-go-brrr/

these are also worth checking out:

* https://github.com/y-crdt/y-crdt (rust implementation started by the creator of Yjs, Kevin Jahns)

* https://github.com/y-crdt/ypy (python bindings for the rust implementation)

* https://github.com/josephg/diamond-types (Seph Gentle's rust implementation of YATA, the algorith behind Yjs)

I found the concept of conflict-free relational data types (CRDTS) interesting as it allows you to have fully offline experiences while also having a conflict-free syncing experience. I was looking for some good libraries and came across automerge and yrs, but both had some rough APIs as they're primarily low-level libraries that are wrapped by TypeScript APIs.

Yrs (Yjs on Rust) maintainer here: we actually had some idea about building extension to Postgres ;) See: https://github.com/y-crdt/y-crdt/issues/220

Hi everyone! Author here. I'm happy to answer questions.

I wrote this a couple years ago. Since then I've been working on my own CRDT called Diamond Types[1], which uses a lot of these ideas to be bonkers fast. I've built several OT based collaborative editing systems, and diamond types is much faster than any of them - though rust and wasm might be the real MVPs here. I wrote a follow-up to this article last year when I got that working, talking about how some of the optimizations work. That article is here[2].

A fair bit has changed since I wrote that article. Yjs has started a rewrite in rust (called yrs[3]). And Automerge has apparently dramatically improved performance based on some of the ideas I talk about in this article. Oh, and diamond types has been rewritten from the ground up. Its now about 5x faster than it was last year, by completely changing the internal structure. But thats a story for another day.

Unfortunately I still only support collaborative text editing. Adding full JSON support comes soon, after I document some more of the tricks I'm doing. Its really fun work!

Why do I only support collaborative text editing? Because I care about performance, and text CRDT performance is hard because you have so many individual changes. (One for each keystroke!). Making text editing fast means everything is fast. But we've still got to do the work. To make that happen, my plan is to add full JSON editing support to diamond types using shelf[4]. Shelf is a super simple CRDT which fits in 100 lines of javascript.

[1] https://github.com/josephg/diamond-types/

[2] https://josephg.com/blog/crdts-go-brrr/

[3] https://github.com/y-crdt/y-crdt/tree/main/yrs

[4] https://github.com/dglittle/shelf