martendb.io

What It Is

Marten is a transactional document database and event store for .NET, built on top of PostgreSQL. It focuses on reusing PostgreSQL’s existing JSON support, ACID transaction capabilities, and mature database engine, while providing document database, event stream, event sourcing, and projection capabilities at the application layer. For .NET teams already using PostgreSQL, it can reduce the complexity of introducing a separate document database or event store component.

Core Capabilities

Based on the documentation, Marten offers a fairly deep feature set. On the document side, it supports LINQ queries, raw SQL, and full SQL queries via APIs such as AdvancedSql.QueryAsync/Query, returning documents, scalar values, JSON-serializable objects, and tuples with up to three result types. Large datasets can be streamed with StreamAsync as IAsyncEnumerable. On the event side, it supports event streams, aggregate replay, version conflict control, and both single-stream and multi-stream aggregate projections. Projections can be implemented through convention-based methods such as Create/Apply/ShouldDelete or through explicit code, and they support event metadata, data enrichment, aggregate caching, and side effects such as appending new events or publishing messages via Wolverine.

Language, Ecosystem, and Documentation

The examples in the captured content are all in C#, and the APIs are built around .NET-style constructs such as IDocumentSession, IDocumentStore, Events.Append, and AggregateStreamAsync, so Marten is clearly aimed primarily at the .NET/PostgreSQL stack. In terms of ecosystem, the documentation notes that Wolverine provides first-class support for side effects in Marten projections, and Marten is part of the Critter Stack. The documentation quality is high, with extensive code samples, process explanations, and caveats, such as column ordering for advanced SQL results, limitations around strongly typed identifiers, and the processing flow of the asynchronous Daemon. It is well suited to experienced backend engineers who want to use it in depth.

Pricing and Deployment

The text does not provide information about commercial pricing, hosted services, enterprise support, or payment methods. In terms of deployment, Marten itself appears to be a library embedded in a .NET application, with PostgreSQL as the underlying database. The captured content does not state whether there is an official hosted version, self-hosting installation guide, or commercial SLA.

Pros, Cons, and Best Fit

Its strengths are that it reuses PostgreSQL, provides strong transactional consistency, and unifies document database and event store capabilities. It is well suited to building CQRS systems, event-sourced applications, read model projections, and complex business aggregates. The drawbacks are a non-trivial learning curve: advanced SQL requires understanding Marten’s internal table structure and column ordering, while event projections require the team to have experience with event modeling. The text also does not indicate any commercial support. Marten is best suited for mid-to-senior .NET teams, heavy PostgreSQL users, and business systems that need event sourcing.

Access from China

The captured text does not include information about access from mainland China, mirrors, payment, or network availability, so this is unknown. If access to the official website or package sources is restricted, alternatives such as a custom PostgreSQL JSONB-based implementation, EventStoreDB, MongoDB, or RavenDB may be worth evaluating.