Loom is a conflict-free replicated data type implementation tuned for rich text and nested documents. It supports offline editing, arbitrary reordering, and deterministic convergence without a central authority.
The interesting problem was memory: naive CRDTs grow unboundedly with edit history. Loom uses run-length encoded blocks plus a garbage collector that compacts tombstones once all peers acknowledge a version vector, cutting document size by roughly 85%.
It is used in production by several document and whiteboard products.