The entire retail application is a collection of several components, such as order

management, payments, product management, and so on. Each of

these components offers a wide range of business functionalities.

• Adding or modifying a functionality to a component was extremely expensive owing

to its monolithic nature. Also, to facilitate the overall business requirements, these

components had to communicate with each other.

• The communications between these components were often built on top of

proprietary protocols and standards, and they were based on the point-to-point

communication style. Hence, modifying or replacing a given component was also

quite complicated.

https://www.techtarget.com/whatis/definition/monolithic-architecture