✉️ MyServiceBus

MyServiceBus (working title) is a focused, asynchronous service-bus runtime for enterprises building production systems in Java and .NET, inspired by MassTransit.

It provides a consistent, opinionated broker-backed messaging model while remaining compatible with documented MassTransit transport profiles and a separate, scoped NServiceBus RabbitMQ profile. This makes it possible for Java and .NET services to communicate across platforms and with verified peer runtimes.

The project's motivation is to build on MassTransit's proven model and improve the boundaries MyServiceBus owns—cross-language parity, generated dispatch, explicit compatibility and delivery evidence, a first-class MediatR replacement, and a smaller portable core—while keeping that core permissively open source.

See samples below.

The project is currently in preview. Its production-readiness status, existing evidence, and the gates required before broad enterprise adoption are documented in Enterprise Production Readiness.

Why choose MyServiceBus?

• Extend an existing MassTransit-based .NET estate with Java. Use the documented common subset so Java services can participate without a custom messaging bridge.
• Start a new system in C#, Java, or both. Keep one focused messaging model while choosing the most suitable language for each service.
• Replace MediatR for local application messaging. Use dedicated handler APIs and generated dispatch for in-process commands, queries, and notifications, with no broker required.
• Match the commitment to the project stage. MyServiceBus is MIT-licensed. For teams that do not need—or cannot yet justify—the commercial support and broader feature set of MassTransit v9+, it offers a smaller option with an explicit preview-status trade-off.

The currently verified MassTransit interoperability peer is 8.5.1; that technical test pin is separate from MassTransit v9+ licensing. Read Why Choose MyServiceBus? for the complete decision boundary and Using MyServiceBus as a Mediator for deliberately in-process commands, queries, and notifications, including generated consumer registration and dispatch as an MIT-licensed alternative to current MediatR releases.

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Getting started with .NET

Install the RabbitMQ transport for a broker-backed application. It brings in the core runtime and abstractions transitively:

dotnet add package Sundstrom.MyServiceBus.RabbitMq --version 0.1.0-preview.7

For an application that only needs the core runtime and its in-memory mediator, install the main package directly:

dotnet add package Sundstrom.MyServiceBus --version 0.1.0-preview.7

Continue with the .NET quick start to register the bus, configure RabbitMQ, add a consumer, and publish a message. The feature walkthrough covers the complete C# and Java APIs.

NuGet packages

Package	Purpose
Sundstrom.MyServiceBus	Core messaging runtime and in-memory mediator
Sundstrom.MyServiceBus.Abstractions	Portable message contracts, contexts, and endpoint abstractions
Sundstrom.MyServiceBus.Serialization.Bson	Optional MassTransit-compatible BSON envelope serialization
Sundstrom.MyServiceBus.PostgreSql	PostgreSQL transactional outbox and inbox persistence
Sundstrom.MyServiceBus.Inspection	Queryable bus metadata and topology inspection APIs
Sundstrom.MyServiceBus.Monitoring	Optional batched runtime monitoring exporter and collector protocol
Sundstrom.MyServiceBus.RabbitMq	RabbitMQ transport and configuration integration
Sundstrom.MyServiceBus.AzureServiceBus	Verified-preview Azure Service Bus transport for direct send and publish/subscribe
Sundstrom.MyServiceBus.AmazonSqs	Amazon SQS queues and SNS publish/subscribe transport
Sundstrom.MyServiceBus.Testing	In-memory test harness and testing utilities

All packages currently use the same preview version. Install Sundstrom.MyServiceBus.Testing separately in test projects when the test harness is needed.

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Getting started with Java

Add the RabbitMQ module to a Gradle application. It brings in the Java runtime and its foundational modules transitively:

dependencies {
    implementation 'io.github.marinasundstrom.myservicebus:myservicebus-rabbitmq:0.1.0-preview.7'
}

For Maven applications:

<dependency>
  <groupId>io.github.marinasundstrom.myservicebus</groupId>
  <artifactId>myservicebus-rabbitmq</artifactId>
  <version>0.1.0-preview.7</version>
</dependency>

Continue with the Java quick start or the detailed Java guide.

Maven Central artifacts

Artifact	Purpose
io.github.marinasundstrom.myservicebus:myservicebus	Core messaging runtime and in-memory mediator
io.github.marinasundstrom.myservicebus:myservicebus-processor	Optional JSR 269 processor for generated consumer catalogs and direct method invokers
io.github.marinasundstrom.myservicebus:myservicebus-serialization-bson	Optional MassTransit-compatible BSON envelope serialization
io.github.marinasundstrom.myservicebus:myservicebus-postgresql	PostgreSQL transactional outbox and inbox persistence
io.github.marinasundstrom.myservicebus:myservicebus-inspection	Queryable bus metadata and topology inspection APIs
io.github.marinasundstrom.myservicebus:myservicebus-monitoring	Optional batched runtime monitoring exporter and collector protocol
io.github.marinasundstrom.myservicebus:myservicebus-abstractions	Portable messaging contracts and abstractions
io.github.marinasundstrom.myservicebus:myservicebus-di	Dependency-injection abstractions
io.github.marinasundstrom.myservicebus:myservicebus-logging	Logging abstractions and adapters
io.github.marinasundstrom.myservicebus:myservicebus-tasks	Asynchronous task and cancellation abstractions
io.github.marinasundstrom.myservicebus:myservicebus-rabbitmq	RabbitMQ transport and configuration integration
io.github.marinasundstrom.myservicebus:myservicebus-azure-service-bus	Verified-preview Azure Service Bus transport for direct send and publish/subscribe
io.github.marinasundstrom.myservicebus:myservicebus-amazon-sqs	Amazon SQS queues and SNS publish/subscribe transport
io.github.marinasundstrom.myservicebus:myservicebus-testing	In-memory test harness and testing utilities

All Java artifacts use the same version as the corresponding NuGet release.

Runtime monitoring deployment

The optional inspection and exporter APIs are client libraries in the package tables above. The collector and Blazor dashboard are separate deployable applications, published as versioned Linux container images:

ghcr.io/marinasundstrom/myservicebus-monitoring-collector:0.1.0-preview.7
ghcr.io/marinasundstrom/myservicebus-monitoring-dashboard:0.1.0-preview.7

See the runtime monitoring guide for configuration, the live dashboard model, OpenTelemetry boundaries, and the experimental security scope.

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What is MyServiceBus?

MyServiceBus defines a stable messaging runtime with concepts such as:

• publish vs send
• consumers
• request/response
• retries and error handling
• middleware / pipeline behaviors
• scheduling
• in-memory testing

These portable concepts remain consistent across supported transport profiles, while broker-specific capabilities and guarantees remain explicit.

Unlike most Java messaging solutions, MyServiceBus does not require a framework-wide commitment (such as Spring). It can be used as a self-contained runtime, integrated into an existing application, or composed via factories and decorators—depending on project needs.

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Goals

• Provide a focused, community-driven runtime for production-critical MassTransit-style broker-backed messaging scenarios.
• Make delivery, failure, security, operational, compatibility, and support guarantees explicit and evidence-backed.
• Preserve a MassTransit-compatible messaging model across Java and .NET.
• Enable Java services to easily connect with .NET/C# services using shared messaging semantics.
• Offer a familiar experience for developers coming from .NET.
• Maintain feature parity and consistent behavior between the C# and Java implementations.
  See the design guidelines for architectural and behavioral parity.

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Features

• Fire-and-forget message sending
• Publish/subscribe pattern
• Request/response pattern (RequestClient and scoped client factory)
• RabbitMQ transport
• Verified-preview Azure Service Bus transport with corresponding C# and Java implementations
• In-memory mediator and test harness
• Compatibility with MassTransit message envelopes
• Neutral Raw JSON messages
• Verified NServiceBus RabbitMQ directed-send interoperability for C# and Java
• Fault and error handling semantics aligned with MassTransit
• Middleware / pipeline behaviors
• OpenTelemetry support
• Java and C# implementations with aligned semantics
• Optional generated consumer catalogs and experimental AOT paths for .NET NativeAOT and GraalVM Native Image

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Specification

• MyServiceBus Specification
• ServiceBus Transport Specification
• Differences from MassTransit
• NServiceBus interoperability

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Building from source

Prerequisites

• .NET SDK
• Java (for the Java modules): JDK 17
• Gradle

Building

• .NET

  dotnet restore
  dotnet build

• Java Java build and run instructions are documented in src/Java/README.md.

Running tests

• .NET

  dotnet test

• Java

  gradle test

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Quick start

Minimal steps to configure MyServiceBus and publish a message. For a broader tour of the library, see the feature walkthrough, which covers both basic and advanced usage.

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C#

Register the bus with the ASP.NET host builder:

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddServiceBus(x =>
{
    x.AddConsumer<SubmitOrderConsumer>();

    x.UsingRabbitMq((context, cfg) =>
    {
        cfg.ConfigureEndpoints(context);
    });
});

var app = builder.Build();

await app.StartAsync();

var bus = app.Services.GetRequiredService<IMessageBus>();

Define the messages and consumer:

public record SubmitOrder(Guid OrderId);
public record OrderSubmitted(Guid OrderId);

class SubmitOrderConsumer : IConsumer<SubmitOrder>
{
    public Task Consume(ConsumeContext<SubmitOrder> context) =>
        context.Publish(new OrderSubmitted(context.Message.OrderId));
}

Publish the SubmitOrder message 🚀:

await bus.Publish(
    new SubmitOrder(Guid.NewGuid()),
    ctx => ctx.Headers["trace-id"] = Guid.NewGuid()
);

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Java

Register the bus:

ServiceCollection services = ServiceCollection.create();

services.from(MessageBusServices.class)
        .addServiceBus(cfg -> {
            cfg.addConsumer(SubmitOrderConsumer.class);
            cfg.using(
                RabbitMqFactoryConfigurator.class,
                (context, rbCfg) -> rbCfg.configureEndpoints(context)
            );
        });

ServiceProvider provider = services.buildServiceProvider();
MessageBus bus = provider.getService(MessageBus.class);

bus.start().join();

Define the messages and consumer:

record SubmitOrder(UUID orderId) { }
record OrderSubmitted(UUID orderId) { }

class SubmitOrderConsumer implements Consumer<SubmitOrder> {
    @Override
    public CompletableFuture<Void> consume(ConsumeContext<SubmitOrder> context) {
        return context.publish(
            new OrderSubmitted(context.getMessage().orderId())
        );
    }
}

Publish the SubmitOrder message:

bus.publish(
    new SubmitOrder(UUID.randomUUID()),
    ctx -> ctx.getHeaders().put("trace-id", UUID.randomUUID())
).join();

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Repository structure

• src/ – C# and Java source code
• test/ – Test projects
• docs/ – Documentation, including the feature walkthrough and specifications Development documents live in docs/development/
• docker-compose.yml – Docker configuration for local infrastructure

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Java Quickstart

See src/Java/README.md for detailed Java build and run instructions, including JDK 17 prerequisites and running the test application.

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Contributing

Contributions are welcome! Please run dotnet test before submitting a pull request and follow the coding conventions described in AGENTS.md.

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License

This project is licensed under the MIT License.