Dapr is a portable, serverless, event-driven runtime that makes it easy for developers to build resilient, stateless and stateful microservices that run on the cloud and edge and embraces the diversity of languages and developer frameworks.
Dapr codifies the best practices for building microservice applications into open, independent, building blocks that enable you to build portable applications with the language and framework of your choice. Each building block is independent and you can use one, some, or all of them in your application.
Dapr consists of a rich set of buildingblocks that will help developers in building microservices. Applications that make use of Dapr can implement one or multiple buildingblocks; so it’s not required to implement them all.
A building block is an abstract implementation of a certain pice of functionality that can be configured centrally. For example, your application could implement the Dapr publish/subscribe building block and centrally is configured that publish/subscribe is done using RabbitMQ. If you later decide to stop using RabbitMQ and go for Azure Service Bus, you only have to update the central configuration. The code of your microservices doesn’t require any changes.