A modular architecture in which an application is divided into smaller, independent services that are loosely coupled and communicate with each other through APIs. Typically, each microservice is responsible for a specific function or feature of the application, and can be developed, deployed, and scaled independently.
This modular architecture allows for greater flexibility, scalability, and maintainability compared to traditional monolithic applications.
Why microservices?
- Scalability
- scalable at a service level - meaning the whole system need not scale for a particular service.
- The scalability achieved is also flexible and on-demand
- Maintainability
- Easy to onboard new developers
- allows parallel development, deployment and testing
- service level debugging
- Reliability
- fault tolerant - no single point of failure
- resilient if designed well, can pick up where it failed
- Availability
- through horizontal scaling
See also Why distributed systems?
Why not microservices?
- harder to design
- might be overkill for small teams
- lots of moving parts - increases system complexity for understanding and management
- typically slower than monoliths, because of RPCs/API calls over the network
- code duplication - classes/objects may be shared, More APIs & RPCs are needed, common functionalities might need to be shared