Eveneum is a simple, developer-friendly Event Store with snapshots, backed by Azure Cosmos DB.

var database = "Eveneum";
var collection = "Events";

var client = new CosmosClient("connection-string");
var databaseResponse = await client.CreateDatabaseIfNotExistsAsync(database);
var containerResponse = await databaseResponse.Database
    .CreateContainerIfNotExistsAsync(new ContainerProperties(collection, "/StreamId"));

IEventStore eventStore = new EventStore(client, database, collection);
await eventStore.Initialize();

var streamId = Guid.NewGuid().ToString();
EventData[] events = GetEventsToWrite();
await eventStore.WriteToStream(streamId, events);
await eventStore.CreateSnapshot(streamId, 7, GetSnapshotForVersion(7));
await eventStore.ReadStream(streamId);

The aim of the project is to provide a straightforward implementation of Event Store by utilising the features of Azure Cosmos DB. The library will benefit from automatic indexing, replication and scalability offered by Cosmos DB.

• Ability to store and read stream of events in a single method call. The library will handle retries and batching,
• Ability to store and read snapshots, including support for reading a snapshot and only consecutive events,
• Ability to customize the schema of documents stored in Cosmos DB to allow for rich querying capabilities,
• Built-in optimistic concurrency checks,
• "Cosmos DB Change Feed"-friendly design to enable building independent projections using Change Feed.

All documentation is available in wiki

Eveneum has been used in Production in a multi-tenant system since Oct 2018, is considerred stable and is being maintained. Any bugs will be fixed as priority.

Please create issues for all bugs / feature requests here.

If you're looking for training / mentoring in the areas of event-sourcing / CosmosDB than contact me directly.