Y-Octo
July 29, 2026 · View on GitHub
Y-Octo is a high-performance CRDT implementation compatible with yjs.
Introduction
Y-Octo is a tiny, ultra-fast CRDT collaboration library built for all major platforms. Developers can use Y-Octo as the Single source of truth for their application state, naturally turning the application into a local-first collaborative app.
Y-Octo also has interoperability and binary compatibility with yjs. Developers can use yjs to develop local-first web applications and collaborate with Y-Octo in native apps alongside web apps.
Who are using
AFFiNE is using y-octo in production. There are Electron app and Node.js server using y-octo in production.
Mysc is using y-octo in the Rust server, and the iOS/Android client via the Swift/Kotlin bindings (Official bindings coming soon).
Performance
| Tasks | automerge v0.10.0 (2026-06-05) | loro v1.13.7 (2026-07-15) | diamond-types v1.0.0 (2022-08-25) | y-octo v0.1.0 (2026-07-27) | yrs v0.27.3 (2026-07-13) |
|---|---|---|---|---|---|
| automerge - apply | 3862.98 ± 3.78 ms | 45.66 ± 0.06 ms | 9.28 ± 0.02 ms | 203.74 ± 0.43 ms | 2387.79 ± 12.86 ms |
| automerge - decode time | 206.94 ± 1.17 ms | 73.09 ± 0.95 us | 1.49 ± 0.00 ms | 37.51 ± 0.05 ms | 2.32 ± 0.01 ms |
| automerge - encode time | 1.71 ± 0.05 ms | 219.52 ± 3.05 us | 672.47 ± 7.71 us | 9.70 ± 0.02 ms | 459.53 ± 0.91 us |
| concurrent list inserts | 93.09 ± 0.45 ms | 164.31 ± 0.41 ms | 34.10 ± 0.06 ms | 7.88 ± 0.02 ms | 7.55 ± 0.03 ms |
| list_random_insert_1k | 248.13 ± 0.25 ms | 10.22 ± 0.10 ms | 2.61 ± 0.00 ms | 2.06 ± 0.01 ms | 3.16 ± 0.00 ms |
| parallel applying automerge edits | 57192.59 ± 464.50 ms | 10216.50 ± 120.33 ms | 96.83 ± 0.37 ms | 1157.47 ± 14.51 ms | 5416.23 ± 54.97 ms |
The parallel workload applies the full Automerge trace to two replicas in random batches of 1–1000 local edits, synchronizes after each pair of batches, and verifies replica convergence.
Ref: https://github.com/darkskygit/crdt-bench-native
Features
- ✅ Collaborative Text
- ✅ Read and write styled Unicode compatible data.
- ✅ Add, modify and delete text styles.
- 🚧 Embedded JS data types and collaborative types.
- ✅ Collaborative types of thread-safe.
- Collaborative Array
- ✅ Add, modify, and delete basic JS data types.
- ✅ Recursively add, modify, and delete collaborative types.
- ✅ Collaborative types of thread-safe.
- 🚧 Recursive event subscription
- Collaborative Map
- ✅ Add, modify, and delete basic JS data types.
- ✅ Recursively add, modify, and delete collaborative types.
- ✅ Collaborative types of thread-safe.
- 🚧 Recursive event subscription
- 🚧 Collaborative Xml (Fragment / Element)
- ✅ Collaborative Doc Container
- ✅ YATA CRDT state apply/diff compatible with yjs
- ✅ State sync of thread-safe.
- ✅ Store all collaborative types and JS data types
- ✅ Update event subscription.
- 🚧 Sub Document.
- ✅ Yjs binary encoding
- ✅ Awareness encoding.
- ✅ Primitive type encoding.
- ✅ Sync Protocol encoding.
- ✅ Yjs update v1 encoding.
- 🚧 Yjs update v2 encoding.
Testing & Linting
Put everything to the test! We've established various test suites, but we're continually striving to enhance our coverage：
- Rust Tests
- Unit tests
- Loom multi-threading tests
- Miri undefined behavior tests
- Address Sanitizer memory error detections
- Fuzzing fuzzing tests
- Node Tests
- Smoke Tests
- Eslint, Clippy
Related projects
- OctoBase: The open-source embedded database based on Y-Octo.
- yjs: Shared data types for building collaborative software in web.
Maintainers
Why not yrs
License
Y-Octo are MIT licensed.