What Is Software Architecture? Principles and Best Practices
What software architecture really is
Architecture is the structural blueprint that decides how to split and connect the parts of software. It affects not only functionality but also modifiability, reliability, performance, security, and operability. There is no single right answer; the basic stance is to choose the most balanced option for your goals and constraints.
Basic design principles
Start simple and avoid building what you don’t need yet—this reduces failure. Each module should focus on a single responsibility, with high internal cohesion and loose external coupling. Make exposed boundaries (interfaces) explicit and hide internal implementations so swapping components and testing become easier.
The layered architecture style
The first approach beginners should learn is layered architecture. Separate layers that handle input/output (UI and controllers), execute use cases (application), hold the core business rules (domain), and cover details such as databases and external services (infrastructure). Have upper layers depend on the “abstractions” of lower layers, and ensure the domain does not directly know framework or database details; this makes the system more resilient to change.
Dependencies and separation of concerns
Make dependency directions point toward the business side, and treat external I/O as replaceable. Separate the roles of the user interface, business rules, and data access, and connect them with minimal touchpoints. This way, even when changing the UI or database, you can protect the core logic.
Basics of data design
Align terminology across the team, and visualize relationships between entities with simple diagrams or notes. Decide which component is the “source of truth” for which data; components other than the owner should stick to read-only access or asynchronous synchronization. Make schema changes incrementally in a compatibility-preserving order, and choose an ID scheme that minimizes collisions.
Basics of API design
For APIs that integrate with external systems, REST is an easy-to-understand first choice: model resources as nouns and express operations with HTTP methods. Human-readable URIs, appropriate HTTP status codes, and a consistent error format improve client implementations and operational stability. When backward-incompatible changes are necessary, use versioning and plan a phased migration.
Guidelines for monoliths and microservices
It’s prudent to start with a modular monolith. Even with a single deployment unit, if you clarify internal boundaries, you can split it later when needed. Consider service decomposition once you can clearly see the value of team and deployment independence; this reduces the risk of failure.
Basics of testing and operations
Emphasize fine-grained unit tests, and cover only critical touchpoints with integration and end-to-end tests to balance development speed and reliability. Structure logs and attach correlation IDs, and monitor basic metrics such as request volume, error rate, and response time to speed up anomaly detection, root-cause analysis, and improvements. Additionally, prepare deployment and rollback procedures in advance; they are the foundation of operations.