When will you go for microservice & when will you go for monoliths?

If your company does not have appetite for below, then do NOT go for microservices

• Rapid provisioning (Infrastructure)
• Basic monitoring
• Rapid application deployment (deployment as well as rollback)
• DevOps culture

Another very important point is, if you cannot define the service boundary right at first place, then it will be very difficult to fix later in microservices.

Disadvantages of Microservice

Complexity – Microservices are distributed systems. Application needs to make remote calls. And remote calls tends to fail. This brings in complexity.

Consistency – Each microservices has its own data store. Hence only eventual consistency is possible.

Transactions – Managing transactions needs additional efforts.

Domain boundary – If you have defined the domain boundary (bounded context in DDD) wrong in first place, then it’s very difficult to fix in Microservice.

Advantages of Microservice

Scalability – It’s easy to scale in or scale out services depending on business need. Also doesn’t have to scale the entire application.

Availability – even if one service is down, application can be functional.

Partial deployment – it’s possible to deploy changes to specific to a microservices. This is faster compared to deploying the entire application.

Independently upgradable – each microservices are like components, it’s possible to independently upgrade or replace them.

Multiple platforms/technology - software development can be done using different technologies.