useR! 2026

useR! Conference in 2026 is being hosted in Warsaw, bringing together data scientists, statisticians, and researchers from across the world.

Charlie Gao will present on “CRDTs for R: Conflict-Free Data Structures for Real-Time Collaboration”.

Description:

Collaborative data analysis presents a fundamental concurrency problem: when multiple users modify the same data simultaneously, how should conflicts be resolved? Traditional approaches rely on locking or central arbitration, but conflict-free replicated data types (CRDTs) offer a principled alternative. A CRDT is a data structure whose concurrent operations are guaranteed to converge to the same state, regardless of the order in which they are applied. This mathematical property — strong eventual consistency — eliminates the need for conflict resolution logic entirely.

We introduce CRDTs to the R ecosystem through automerge, an open-source package developed at Posit that natively bridges R’s data model with the Automerge Rust CRDT engine. Collaborative documents — maps, lists, and text — appear as familiar R objects, but every edit is tracked as an individual operation under the hood. When documents are modified concurrently, changes merge automatically.

Beyond real-time document editing, CRDTs open up new possibilities for the R ecosystem: shared annotation of datasets across a research team, collaborative model specification, or any workflow where multiple analysts need to work on the same objects without coordination overhead. We make this concrete with a live demonstration: audience members will open a Shiny application on their own devices and edit shared state together, watching changes from every participant merge seamlessly in real time.