gRPC is the next generation modern API framework to build Microservices. This enables to build APIs different use case especislly Bi-directional streaming of data between applications. It's much better traditional RESTful framework in performance and efficiency.
gRPC uses Protocol Buffers as data exchange format which is much faster than JSON and light weight.
To know more about the gRPC, watch the video: https://youtu.be/TagQoZhMhG8