abyo-crdt is a Pure Rust CRDT library combining Fugue-Maximal lists, Peritext rich text, and an order-statistic AVL tree for O(log N) operations across the board. 167 tests, 3.3M+ fuzz runs, exhaustive stateright model checking, Yjs/Quill Delta interop, WASM + Python bindings. This post walks through the algorithm choices, the AVL bug adversarial fuzz caught before release, and the head-to-head numbers vs yrs.