Microservices are a modern software development approach that refers to the splitting of software into a suite of small services that are easier to develop, debug, deploy, and maintain. Microservices are tiny, independent servers that act as single business functions. For example, if you have an e-commerce suite that works as a monolith, you could split it into small servers that have limited responsibility and carry out the same tasks. One microservice could handle user authorization, the other could handle the users' shopping carts, and the remaining services could handle features such as search functionality, social-media integration, or recommendations.

Microservices can either interact with a database or be connected to other microservices. To interact with a database, microservices can use different protocols. These might include HTTP or REST, Thrift, ZMQ, AMQP for the messaging communication style, WebSockets for streaming data, and even the old-fashioned Simple Object Access Protocol (SOAP) to integrate them with the existing infrastructure. We will use HTTP and REST in this book, because this is the most flexible way to provide and interact with the web API. We'll explain this choice later.

Microservices have the following advantages over monolithic servers:

• You can use different programming languages
• The code base of a single server is smaller
• They have an independent DevOps process to build and deploy activities
• They can be scaled depending on their implementation
• If one microservice fails, the rest will continue to work
• They work well within containers
• Increased isolation between elements leads to better security
• They are suitable for projects involving the Internet of Things
• They are in line with the DevOps philosophy
• They can be outsourced
• They can be orchestrated after development
• They are reusable

There are, however, a few drawbacks of microservices. These include the following:

• Too many microservices overload the development process
• You have to design interaction protocols
• They can be expensive for small teams

A microservices architecture is a modern approach that can help you achieve the goal of having loosely coupling elements. This is where the servers are independent from one another, helping you to release and scale your application faster than a monolithic approach, in which you put all your eggs in one basket.