Comment by josephg

> To be clear, we ARE arguing CRDTs needlessly complex for the centralized server use case.

I've been working in the OT / CRDT space for ~15 years or so at this point. I go back and forth on this. I don't think its as clear cut as you're making it out to be.

- I agree that OT based systems are simpler to program and usually simpler to reason about.

- Naive OT algorithms perform better "out of the box". CRDTs often need more optimisation work to achieve the same performance.

- But with some optimisation work, CRDTs perform better than OT based systems.

- CRDTs can be used in a client/server model or p2p. OT based systems generally only work well in a centralised context. Because of this, CRDTs let you scale your backend. OT (usually) requires server affinity. CRDT based systems are way more flexible. Personally I'd rather complex code and simpler networking than the other way around.

- Operation based CRDTs can do a lot more with timelines - eg, replaying time, rebasing, merging, conflicts, branches, etc. OT is much more limited. As a result, CRDT based systems can be used for both realtime editing or for offline asyncronous editing. OT only really works for online (realtime) editing.

(For anyone who's read the papers, I'm conflating OT == the old Jupitor based OT algorithm that's popular in google docs and others.)

CRDTs are more complex but more capable. They can be used everywhere, and they can do everything OT based systems can do - at a cost of more code.

You can also combine them. Use a CRDT between servers and use OT client-to-server. I made a prototype of this. It works great. But given you can make even the most complex text based CRDT in a few hundred lines anyway[1], I don't think there's any point.

[1] https://github.com/josephg/egwalker-from-scratch