JasperFx.Events

Foundational event store abstractions and projection infrastructure for the Critter Stack. Consumed by Marten (Postgres) and Polecat (SQL Server) so a projection or async-daemon scenario written against JasperFx.Events works across both products.

Provides:

• Projections — ProjectionBase, IInlineProjection, snapshot / single-stream / multi-stream variants, and the SnapshotLifecycle enum.
• Async daemon — AsyncShard, ISubscriptionExecution, projection lifecycle and shard role semantics.
• Slicing & grouping — SliceGroup, EventSlice, IEventSlicer for fan-out projection topologies.
• Event metadata — IEvent, IEventRegistry, type registry primitives.
• Descriptors — EventStoreUsage and friends, surfaced through IEventStoreUsageSource to monitoring tools (CritterWatch).

Quick start

public class OrderProjection : SingleStreamProjection<Order, Guid>
{
    public Order Create(OrderPlaced e) => new(e.OrderId, e.Total);
    public Order Apply(OrderShipped e, Order state) => state with { Shipped = true };
}

Documentation

Full docs at https://jasperfx.net.

Repo: github.com/JasperFx/jasperfx.