Scenarios

These are recipes: “I need to do X — how?” Each is short and assumes you’ve been through Get started and understand the core concepts. For the why and the full options, follow the links into the reference.

Recipe	When you reach for it
Rebuild a read model	You changed a projection and need the read model to reflect the new logic
Enforce a unique value	A value (email, ISBN, username) must be unique across a stream
React to an event	An event should trigger a notification, external call, or follow-up fact
Get read models	You need one instance, a collection, a page, or live updates
Test a slice	You want to verify event appends and derived read model state in-process
Evolve an event’s shape	An event type needs to change without rewriting history

Missing a recipe you expected? The feature guides and Troubleshooting cover the long tail.