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Matthew Weidner

@mweidner.bsky.social

Collaborative software at Common Curriculum / CMU I write about CRDTs etc: mattweidner.com

Matthew Weidner @mweidner.bsky.social · 30/03/2026

Fun academic find: the core idea of server reconciliation (a general approach to real-time collaboration that's simpler than Operational Transformation or CRDTs) already appears in an MIT tech report from 1985.

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Matthew Weidner @mweidner.bsky.social · 05/12/2025

From the ~1st collaborative text editing paper: if two users do "delete char @ index 7" concurrently, no serial ordering gives the correct answer. So the authors abandon serializability, leading to OT/CRDTs. But if you rephrase the ops as "delete char @ <per-char id>", both serial orders work!

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Matthew Weidner @mweidner.bsky.social · 17/04/2025

My most recent blog post (from last summer): Architectures for real-time collaborative apps using a central server. It includes classic CRDT/OT approaches, why those might be overkill, and a classification table for existing apps/tools. mattweidner.com/2024/06/04/s...

Screenshot of classification table from the blog post

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