Explore the Symfony Messenger component in this 44-minute conference talk from the International PHP Conference. Learn how to implement message-based architecture in existing applications, focusing on microservice-style development with Symfony 4 and Flex. Discover the concepts and principles behind Messenger, including message buses, handlers, subscribers, and various transport options like AMQP, Redis, and Doctrine. Dive into practical scenarios, addressing challenges in distributed systems, configuring buses, implementing retry strategies, and leveraging middleware for enhanced functionality. Gain insights into envelope handling, failure transport, and the importance of middleware order in your Symfony applications.