Event‑Driven Design

Otso treats every change as an immutable event. This makes history auditable and projections easy to rebuild.

Why events work for Otso

• Simplifies imports from unreliable APIs.
• Enables replay and migration to new projections.
• Encourages small, composable plugins.

Drawbacks and mitigations

• Event logs grow forever → use snapshots or pruning for old events.
• Higher initial complexity → start with high level helpers like createEvent.

Practical rules of thumb

1. Capture the smallest meaningful fact as an event.
2. Keep events immutable; derive views elsewhere.
3. Name projections after the query they serve (e.g., latest_notes).