sssync: Simple Stateless Sync

WARNING: THIS IS NOWHERE NEAR DONE

Sync protocol

• Client can make requests to an endpoint that returns snapshots for named functions + argument combos
• Server is responsible for sending client a delta stream of updates
• Client writes to local cache and server using named + typed events

Open questions

• Provide both IVM and non-IVM versions?
• How to support SSR + incognito usage?
• Provide both IDB (sync) and SQLite (async) versions?
• Semantics around temporary fetch vs. persist results
• Use route metadata to choose loader strategy (workspace, cold-bootstrap, public/share)?
• Can we combine online and offline edits? Rollback?
• When resetting local state, can we download server state first, then swap over?

nice-to-haves

• Undo-redo support
• Expose cache clearance
• Full-text search (use FTS5)
• UI state persistence (with screen width options)
• Design schema management + migration system
• Query lifecycles
• Sync status + metadata + satisfied queries
• Devtools with test modes
• Update batching API (for sliders)
• Preloading API (like Linear?)
• Event => UI mapping for toasts
• Persistent (and typed) client-only stores
• Images handling, like icons (https://colanode.com/blog/emojis-icons-offline-with-sqlite/)
• Offline-capable blob uploads (https://docs.powersync.com/client-sdks/advanced/attachments)
• Data seeding
• Simulate bugs through double sending, out of order handling
• Request delaying to test loading UI
• Semantic annotation layer to events
• Rewind

speculative

• Build a SQLite-only server-side zero-cache that the client can request data from, but queries run just once and delta sync does the rest