Take a quick refresher on the building blocks of modern systems, each component of which is a completely scalable application.

Deep Dive into System Design Interview

In this module, we’ll learn about the building blocks of modern systems, each component of which is a completely scalable application itself. These building blocks are the foundation for designing scalable applications. Each building block serves a unique purpose and has its own importance in scalable applications.

Basic Building Blocks for Modern System Design

How is the order associated with messages?

In a basic queue, message order is determined by the sequence in which messages are enqueued. Messages are then consumed and processed in the same order.

For concurrent producers putting messages into the same queue, the order is not well-defined until producers provide ordering information, such as timestamps or sequence numbers. Without any ordering information, the queue puts messages in whatever order they arrive at the service.

With multiple consumers reading from the same queue, preserving ordering becomes more complex. Although the queue can deliver messages in enqueue order, concurrent consumers may process them in parallel, requiring application-level ordering guarantees. The queue can attach metadata such as a sequence number or timestamp to help consumers enforce ordering.


Discover the essential design considerations for distributed messaging queues, focusing on message ordering and concurrency. Define strict and best-effort ordering techniques, analyzing how sorting impacts performance and latency. Learn effective strategies for managing concurrent queue access.

Considerations of a Distributed Messaging Queue’s Design

Ordering of messages

Best-effort ordering