Microservices are independently deployable services aligned to business capabilities. A service should own a cohesive responsibility and the data needed to fulfill it. Splitting by technical layer—for example, a service for every database table—often creates chatty dependencies and coordinated deployments.

Domain-driven design uses concepts such as bounded contexts, ubiquitous language, aggregates, and domain events to discover boundaries. Two teams may use the same word differently; a “customer” in billing may have different rules from a “customer” in support. Explicit contexts reduce accidental coupling.

Microservices introduce network latency, partial failure, distributed tracing, service discovery, deployment coordination, and data consistency challenges. Independent deployment is useful only if teams can operate services safely and contracts are managed carefully.