Microservice architecture — how do services communicate with each other? RabbitMQ vs Kafka — what are the differences?

In a microservices architecture, services communicate with each other through well-defined interfaces, most often using HTTP/REST protocols, gRPC, or message brokers for asynchronous interaction.

RabbitMQ vs Kafka — differences:

• RabbitMQ is a message broker supporting queues, focused on message routing and guaranteed delivery. It supports various exchange models (queues, topics, routing). It is suitable for tasks requiring high delivery guarantees and complex routing logic.

• Kafka is a distributed data streaming platform focused on high throughput and storing messages in topics with the ability to re-read. It is suitable for processing large data streams and building event-driven systems.

In brief:

• RabbitMQ is better for complex routing and guaranteed delivery.
• Kafka is better for scalable stream processing and message history storage.

Example of using RabbitMQ in C# (sending a message):

var factory = new ConnectionFactory() { HostName = "localhost" };
using(var connection = factory.CreateConnection())
using(var channel = connection.CreateModel())
{
    channel.QueueDeclare(queue: "task_queue", durable: true, exclusive: false, autoDelete: false, arguments: null);
    string message = "Hello World!";
    var body = Encoding.UTF8.GetBytes(message);
    channel.BasicPublish(exchange: "", routingKey: "task_queue", basicProperties: null, body: body);
    Console.WriteLine(" [x] Sent {0}", message);
}