Use ory/hydra with/for gRPC compliant authentication? Yes

https://github.com/grpc/grpc/tree/master/examples/objective-c/auth_sample

Why gRPC (Google RPC)

[0] https://en.wikipedia.org/wiki/GRPC

gRPC (gRPC Remote Procedure Calls) is an open source remote procedure call (RPC) system initially developed at Google. It uses HTTP/2 for transport, Protocol Buffers as the interface description language, and provides features such as authentication, bidirectional streaming and flow control, blocking or nonblocking bindings, and cancellation and timeouts. It generates cross-platform client and server bindings for many languages. Most common usage scenarios include connecting services in microservices style architecture and connect mobile devices, browser clients to backend services.

gRPC Background

[1] https://grpc.io/about/

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 main usage scenarios:

  • Efficiently connecting polyglot services in microservices style architecture
  • Connecting mobile devices, browser clients to backend services
  • Generating efficient client libraries

Core Features that make it awesome:

  • Idiomatic client libraries in 10 languages
  • Highly efficient on wire and with a simple service definition framework
  • Bi-directional streaming with http/2 based transport
  • Pluggable auth, tracing, load balancing and health checking

gRPC Documentation

[2] https://grpc.io/docs/guides/

Overview

gRPC is designed to work with a variety of authentication mechanisms, making it easy to safely use gRPC to talk to other systems. You can use our supported mechanisms - SSL/TLS with or without Google token-based authentication - or you can plug in your own authentication system by extending our provided code.

gRPC also provides a simple authentication API that lets you provide all the necessary authentication information as Credentials when creating a channel or making a call.

Working with Protocol Buffers

By default gRPC uses protocol buffers, Google’s mature open source mechanism for serializing structured data (although it can be used with other data formats such as JSON). Here’s a quick intro to how it works. If you’re already familiar with protocol buffers, feel free to skip ahead to the next section.

The first step when working with protocol buffers is to define the structure for the data you want to serialize in a proto file : this is an ordinary text file with a .proto extension. Protocol buffer data is structured as messages , where each message is a small logical record of information containing a series of name-value pairs called fields .

[3] https://en.wikipedia.org/wiki/Protocol_Buffers