Silverback

Simplicity at its core. Flexibility at its peak. Effortless messaging for .NET.

Silverback is a message bus and broker integration library to build event-driven architectures with first-class support for Apache Kafka and MQTT.

Documentation, guides, and samples are available at https://silverback-messaging.net.

Produce and Consume in a Few Lines

Configure the broker connection, the producer and consumer endpoints, and a subscriber. Silverback takes care of serialization, headers, error handling and delivery.

services.AddSilverback()
    .WithConnectionToMessageBroker(options => options.AddKafka())
    .AddKafkaClients(clients => clients
        .WithBootstrapServers("PLAINTEXT://localhost:9092")
        .AddProducer(producer => producer
            .Produce<OrderCreated>(endpoint => endpoint
                .ProduceTo("orders")))
        .AddConsumer(consumer => consumer
            .WithGroupId("billing")
            .Consume<OrderCreated>(endpoint => endpoint
                .ConsumeFrom("orders")
                .OnError(policy => policy.Retry(3).ThenSkip()))))
    .AddSingletonSubscriber<OrderCreatedHandler>();

// Publish: the message is routed to the "orders" topic
await publisher.PublishAsync(new OrderCreated(orderId));

// Consume: the subscriber is invoked for each consumed message
public class OrderCreatedHandler
{
    public Task HandleAsync(OrderCreated message) => ...;
}

Follow the Quickstart for a complete, runnable walkthrough.

Why Silverback

• Kafka-first, not Kafka-only – a consistent, fluent API for Kafka and MQTT that still surfaces partitions, keys, tombstones and transactions.
• Reliable by design – transactional outbox, error policies (retry, skip, move) and storage-backed offsets and locks.
• Built for throughput – partition-based parallelism, batch processing, streaming and chunking of large payloads.
• Cross-cutting features – serialization, Schema Registry (JSON, Avro, Protobuf), headers, validation and end-to-end encryption.
• Observable – structured logging, distributed tracing via System.Diagnostics and health checks.
• Testable – in-memory Kafka and MQTT brokers and testing helpers for fast and reliable end-to-end tests.

Packages

Silverback is modular – reference only what you need.

Core:

• Silverback.Core – message bus and core messaging components.
• Silverback.Core.Model – message semantics for event-driven/CQRS scenarios.

Broker integration:

• Silverback.Integration.Kafka – Kafka support.
• Silverback.Integration.MQTT – MQTT support.

Optional features:

• Silverback.Core.Rx – Rx.NET integration.
• Silverback.Integration.Newtonsoft – Newtonsoft.Json serialization.
• Silverback.Integration.Kafka.SchemaRegistry – Confluent Schema Registry integration (Avro, Protobuf and JSON).
• Silverback.Integration.HealthChecks – health checks for the consumers and the outbox.

Storage (for outbox, client-side offsets, distributed locks):

• Silverback.Storage.PostgreSql
• Silverback.Storage.Sqlite
• Silverback.Storage.EntityFramework
• Silverback.Storage.Memory

Testing:

• Silverback.Integration.Testing – broker-independent testing helpers.
• Silverback.Integration.Kafka.Testing – in-memory Kafka broker.
• Silverback.Integration.MQTT.Testing – in-memory MQTT broker.

Supported .NET Versions

Starting with v5, Silverback targets the latest .NET LTS (Long-Term Support) version only. It can run on newer compatible .NET versions (including STS releases), but older frameworks are no longer targeted or supported.

Documentation

• Quickstart – produce and consume via Kafka in five minutes.
• Guides – setup, message bus, producing, consuming and more.
• Samples – runnable Kafka and MQTT examples.
• Migrating from v4 – step-by-step upgrade guide to Silverback 5.
• FAQ and Troubleshooting – answers to the most common questions.
• API Reference – the complete public API.

The v4 documentation is still available at silverback-messaging.net/v4.

Project Status

Continuous Build

Sonar Build

Quality Metrics

Activity

Repository Solutions and Tools

Solutions

Solution	Contents
Silverback.sln	Library source projects, unit and E2E tests, and code/documentation generators
Silverback.Samples.sln	Runnable usage examples; see the samples guide
Silverback.Tests.Extended.sln	Interactive testbench, real-broker integration and stress tests, general benchmarks and version comparisons, with references to the library sources

Testing and Development Tools

Tool	Purpose
Interactive testbench	Windows WPF application for producing messages and managing Docker consumers
Integration tests	xUnit tests against real Kafka and MQTT brokers, including stress workloads and diagnostic controls
Benchmarks	General performance benchmarks and current-versus-historical Silverback comparisons
UpdateOlderVersions.ps1	Scaffold another historical benchmark project
coverage.ps1	Build and test the main solution with coverage, then generate and open an HTML report
docker-compose.yaml	Local Kafka, Schema Registry, MQTT and PostgreSQL infrastructure, with administration UIs
nuget/Update.ps1	Build local Silverback packages for package-based development and samples
.NET tool manifest	Repository-local ReportGenerator installation used by the coverage script

Code and Documentation Generators

The four generator applications are included in the main solution and write generated content to standard output. Shared generator support lives in Silverback.Tools.Generators.Common.

Tool	Purpose
KafkaConfigProxies	Generate Kafka configuration wrappers and builders; also supports Schema Registry configuration
MqttConfigProxies	Generate MQTT configuration wrappers and builders
Docs.Headers	Generate message-header reference tables
Docs.LogEvents	Generate log-event reference tables
docs/build.ps1	Build and serve the DocFX documentation locally; run from the docs directory
docs/publish.ps1	Publish the generated site through a separate gh-pages checkout; supports -NoPush

Build automation is defined in the main pipeline, the Sonar pipeline, and the samples/extended-tests pipeline.

Community

• Issues – report bugs or suggest improvements.
• Discussions – ask questions and share ideas.
• CONTRIBUTING.md – how to contribute.

License

Silverback is open source, licensed under the MIT License and maintained by Sergio Aquilini. See LICENSE.