Before tell you about microservices, let’s see the architecture that prevailed before microservices i.e. the Monolithic Architecture.

Listed down are the challenges of Monolithic Architecture:

1. Inflexible :Monolithic applications cannot be built using different technologies 
2. Unreliable – Even if one feature of the system does not work, then the entire system does not work
3. Unscalable – Applications cannot be scaled easily since each time the application needs to be updated, the complete system has to be rebuilt
4. Blocks Continous Development – Many features of the applications cannot be built and deployed at the same time
5. Slow Development – Development in monolithic applications take lot of time to be built since each and every feature has to be built one after the other
6. Not Fit For Complex Applications – Features of complex applications have tightly coupled dependencies

The main difference we observe is that all the features initially were under a single instance sharing a single database. But then, with microservices, each feature was allotted a different microservice, handling their own data, and performing different functionalities.