gRPC is a modern open source high performance RPC framework that can run in any environment. It can efficiently connect services in and across data centers with pluggable support for load balancing, tracing, health checking and authentication. It is also applicable in last mile of distributed computing to connect devices, mobile applications and browsers to backend services.

The coming end of the HTTP REST protocol?

The arrival of gRPC on the web probably signals the end of the omnipotence of REST APIs. The performance and interoperability requirements for modern systems favor this newcomer.

• gRPC wins in terms of performance. It ensures the transmission of light messages in binary form while REST transmits character strings in JSON format which are heavier on the network. This makes a noticeable difference for smartphones

• All gRPC framework (available to most popular programming languages) ensure flawless boiler-plate code generation for building binary message clients and servers. Automatic generation of these critical entities will save developers precious time ... and avoid errors that are difficult to diagnose!

• Much like Microsoft's WCF framework, gRPC enforces strict specifications. HTTP APIs with JSON messages do not impose any specifications. Unfortunately, today's web developers are constantly debating over HTTP verbs and appropriate return codes. gRP ensures a consistent developer experience across all platforms and across all implementations.

• gRPC, via the HTTP/2 protocol, supports all types of streaming: unary, server-to-client, client-to-server and bi-directional

• gRPC allows the client to manage the behavior of remote procedures: deadlines, timeouts and cancellations

Use cases

• Micro-services where low latency and high onset are required

• Bi-directional point-to-point communication in real time

• Polyglot environments where several programming languages ​​are used: gRPC offers complete frameworks in several languages.

• Environments where network capacity is limited. A gRPC message will always be much lighter than a JSON payload

Weaknesses of gRPC

• Modern browsers do not currently support gRPC. Microsoft's bet is to promote the adoption of Blazor. A framework which offers a gRPC compatible web client

• Being binary buffers, messages exchanged between clients and servers, are not human-readable

• gRPC has limitations in terms of realtime broadcast over a network. For this use case, an async notification frameworks like SignalR is more suitable

• Because it requires HTTP/2 clients, inter-process communication is better served by other technologies that can do without them. For example, Microsoft uses pipes as a lightweight method of rapid communication between processes.

Source

https://docs.microsoft.com/en-us/aspnet/core/grpc/comparison?view=aspnetcore-3.1

https://grpc.io/