Messaging

Core Principles

1. Wolverine is the recommended default — MIT licensed, combines mediator + messaging in one library with built-in outbox, saga support, and convention-based handlers. MassTransit is an alternative but requires a commercial license from v9.
2. Outbox pattern for reliability — Always use the transactional outbox to ensure messages are published only when the database transaction succeeds.
3. Choreography for simple flows, saga for complex — If a workflow has 2-3 steps, use event choreography. If it has compensating actions or complex state, use a saga.
4. Messages are contracts — Put message types in a shared contracts project. Keep them as simple records with primitive types.

Patterns

Wolverine Setup

// Program.cs
builder.Host.UseWolverine(opts =>
{
    // Auto-discover handlers from this assembly
    opts.Discovery.IncludeAssembly(typeof(Program).Assembly);