EventLoom

EventLoom is an opinionated event-sourcing library for .NET 10 and EF Core 10. It gives .NET applications an explicit event model, a dedicated relational event store, aggregate repositories, snapshots, projections, and a transactional outbox.

flowchart LR
    App[Application] --> Domain[Aggregates and events]
    Domain --> Store[EventLoom event store]
    Store --> Postgres[PostgreSQL<br/>distributed production]
    Store --> Sqlite[SQLite<br/>local or single process]
    Store --> Workers[Projections and outbox]

Choose your next step

I want to…	Start here
Evaluate EventLoom from this repository	Installation
Learn the event-sourcing programming model	Build your first aggregate
Decide where and how to persist events	Architecture
Understand correctness and delivery guarantees	Tenancy and ordering and Delivery model
Add EventLoom to an application	Configure the event store
Build read models or external integration	Projections and Outbox and application integration
Run EventLoom in production	Production deployment

The developer model

1. Model business facts as immutable, versioned events.
2. Change aggregate state only by applying those events.
3. Append an event batch atomically with an expected stream version.
4. Build read models and external integration from the committed event log.

The Aggregates and events concept explains why these boundaries matter. The Ordering API sample shows the complete application path in an ASP.NET Core service.

What EventLoom provides

• Aggregate<TId> for event-only state changes and replay through typed Apply(TEvent) methods.
• Stable event names and versions through [EventType], explicit registration, and JSON serialization.
• Deterministic JSON upcaster chains for changing persisted event schemas.
• Transactional append and bounded read APIs with expected-version checks, UUIDv7 event IDs, and authoritative per-tenant offsets.
• A PostgreSQL provider for multi-instance deployments and a SQLite provider for local, embedded, and controlled single-node use.
• Optional required tenancy with a scoped ITenantAccessor.
• A configured AggregateRepository<TAggregate, TId> path that keeps tenant, aggregate type, and stream-ID plumbing out of normal command handlers.
• Checkpointed asynchronous projections, atomic EF projection handlers, and explicitly registered inline projections.

Current status

EventLoom is pre-release software and its NuGet packages are not published yet. Use this repository to evaluate it; package names in examples describe the planned public distribution surface. Check the packages and compatibility reference and configuration reference before relying on a feature that affects persisted data or operational behavior.