Sync
Sync Overview
Cortex Sync is optional and built around client-side encryption with encrypted blob storage.
On this page
Cortex Sync is an optional layer for moving notes between devices while preserving the local folder model. The service should not become the source of truth for your notes.
Ownership model
Markdown files stay on your devices. The sync service is responsible for encrypted blob storage, transfer, version history, and conflict recovery around those local files.
Client-side encryption
Notes are encrypted on the client before upload. The server stores encrypted blobs and the metadata needed to coordinate sync, rather than readable note contents.
const localChange = await readMarkdownFile(path)const encryptedBlob = await encryptOnDevice(localChange, deviceKey)await syncClient.upload({ vaultId, path, blob: encryptedBlob,})History and conflicts
History should make changes understandable across devices. When conflicts happen, Cortex should preserve enough context for recovery instead of silently overwriting local work.
Self-hosting path
The sync architecture should support a hosted service and a self-hostable path. Documentation should avoid absolute security promises and describe the actual boundaries clearly.