Simon Willison’s Weblog

Stop syncing everything. In which Carl Sverre announces Graft, a fascinating new open source Rust data synchronization engine he's been working on for the past year.

Carl's recent talk at the Vancouver Systems meetup explains Graft in detail, including this slide which helped everything click into place for me:

Graft manages a volume, which is a collection of pages (currently at a fixed 4KB size). A full history of that volume is maintained using snapshots. Clients can read and write from particular snapshot versions for particular pages, and are constantly updated on which of those pages have changed (while not needing to synchronize the actual changed data until they need it).

This is a great fit for B-tree databases like SQLite.

The Graft project includes a SQLite VFS extension that implements multi-leader read-write replication on top of a Graft volume. You can see a demo of that running at 36m15s in the video, or consult the libgraft extension documentation and try it yourself.

The section at the end on What can you build with Graft? has some very useful illustrative examples:

Offline-first apps: Note-taking, task management, or CRUD apps that operate partially offline. Graft takes care of syncing, allowing the application to forget the network even exists. When combined with a conflict handler, Graft can also enable multiplayer on top of arbitrary data.

Cross-platform data: Eliminate vendor lock-in and allow your users to seamlessly access their data across mobile platforms, devices, and the web. Graft is architected to be embedded anywhere

Stateless read replicas: Due to Graft's unique approach to replication, a database replica can be spun up with no local state, retrieve the latest snapshot metadata, and immediately start running queries. No need to download all the data and replay the log.

Replicate anything: Graft is just focused on consistent page replication. It doesn't care about what's inside those pages. So go crazy! Use Graft to sync AI models, Parquet or Lance files, Geospatial tilesets, or just photos of your cats. The sky's the limit with Graft.