Microservice Architecture Design Patterns: Decomposition and Integration Patterns (Part 1)

Microservice architecture has become a practical choice for modern application development, but it introduces challenges that require reusable design patterns.

The article first outlines core architectural principles such as scalability, availability, resilience, autonomy, decentralized governance, fault isolation, automated provisioning, and continuous delivery via DevOps.

It then presents the first set of design patterns – the decomposition patterns – including:

Business‑capability decomposition : split the system by distinct business capabilities, treating each capability as an independent service.

Sub‑domain decomposition : use Domain‑Driven Design to identify sub‑domains and bounded contexts, assigning each to a microservice.

Strangler pattern : incrementally replace a monolith by extracting domains one at a time and routing traffic to new services until the legacy system can be retired.

For each pattern the article lists typical problems (e.g., “god classes”, brown‑field migration) and provides concrete solutions.

The second group of patterns – integration patterns – addresses how multiple microservices are accessed and combined:

API‑gateway pattern : a single entry point that routes, aggregates, transforms protocols, and offloads authentication/authorization.

Aggregator pattern : either a composite microservice or the gateway that calls several services, merges results, and returns a unified response.

Client‑side UI composition pattern : front‑end frameworks (Angular, React) build a page from multiple service‑backed UI components, enabling partial refreshes.

The article concludes by summarizing the covered decomposition and integration patterns and previewing the next part, which will discuss database patterns, observability patterns, and cross‑cutting concerns.