I've been looking for a practical OT alternative for our online word processor (https://zoho.com/writer). We already use OT for syncing our realtime edits and exploring CRDTs targetting stronger consistency for tackling offline edits (which are typically huge & defragmented, since the edits are not syncing in realtime)

So the baseline is that OT has a better model for holding state in terms of performance/memory, since the edits can be compiled into plain string types. CRDTs in comparison forces us to hold deleted states as well and demands richer information per unit (character/string/etc) - which makes it harder on the CPU/RAM.

Here's the story as I understand:

1. Automerge tackles this by just moving to a better lower-level runtime: Rust.

2. Yjs handles this by using a similar technique i.e relying on V8's hidden classes to handle the performance optimizations and assuming real-world cases to narrow down and optimize datastructures.

But none of these, seem to be a fundamental breakthrough in the efficiency of the algorithm itself. They all at best look like a workaround and this keeps bothering me.

The gist of the below [1] read is that it is impossible for a human to create a document that Yjs can't handle (even in the worst case scenario). But yes, it handles real-world scenarios particularily well.

The concept of "hidden classes" is super old. It has first been implemented in a fork of smalltalk and then became foundational concept of runtime engines for scripting languages. It is implemented in V8, python, ruby, spidermonkey, ..

Yjs does not assume a "real-world scenario" and it is not optimized for any specific runtime engine. It runs fast in any browser. The benchmarks confirm this. [2]

Yjs is being used in practice by several companies (eg Nimbus Notes with >3 million users) for quite some time now. I'm not aware of any performance problems.

[1]: https://blog.kevinjahns.de/are-crdts-suitable-for-shared-edi... [2]: https://github.com/dmonad/crdt-benchmarks