Microservices
Definition
Microservices is an architectural style where an application is built as a collection of small, independently deployable services, each running in its own process and communicating through lightweight protocols (typically HTTP/REST or gRPC). Each service is organized around a specific business capability and can be developed, deployed, and scaled independently.
Why It Matters
Microservices solve specific problems at scale: allowing large teams to work independently, enabling different components to scale at different rates, and supporting technology diversity where different services can use different programming languages or databases.
However, microservices introduce significant complexity: distributed system challenges (network failures, data consistency, distributed tracing), operational overhead (independent deployment pipelines, monitoring per service), and debugging difficulty (requests spanning multiple services).
The critical insight that many organizations miss: microservices are a solution to organizational and scaling problems, not a default architecture. If your team is smaller than 20 engineers and your application does not have components with dramatically different scaling requirements, microservices may add complexity without proportional benefit.
Key Trade-Offs
- Independent deployment vs. increased operational complexity
- Technology flexibility vs. ecosystem fragmentation
- Team autonomy vs. cross-service coordination overhead
- Granular scaling vs. network latency and failure modes
- Fault isolation vs. distributed debugging complexity
How BAG Uses It
We advocate for the "modulithic" pattern as the default: a single deployable with logical module separation. We recommend extracting into microservices only when production evidence demands it -- different scaling profiles, deployment independence requirements, or technology mismatches. This progressive extraction approach avoids premature distribution while preserving the option to distribute when needed.