Serverless computing is an extension of cloud computing environment that enables software developers to focus solely on their coding activities ignoring the hardware layer. Bear in mind, however, that the name serverless does not imply the absence of hardware somewhere in the universe though. It simply means the programmer focus on writing and running their codes only while the cloud provider provisions enough resources such as processing, storage, memory to undertake their jobs. For this reason, serverless computing is sometimes known as function as a service (FaaS).
In this computing paradigm, customers never possess a piece of hardware; rather they always pay for it depending on their resource consumptions. That where the notion of serverless comes from. Serverless computing is applicable in microservices architecture.