flamego VS grpc-gateway

Flamego and it's predecessor Macaron also allow a lot of flexibility in the handler definition.

it lacks flexibility but i really enjoy grpc-gateway for 99% of my work

https://github.com/grpc-ecosystem/grpc-gateway

gRPC Gateway is a protoc plugin that reads gRPC service definitions and generates a reverse proxy server that translates a RESTful JSON API into gRPC.

I don't have any example that's public atm, but the guide in grpc-gateway is pretty clear/can be followed step by step.

https://github.com/grpc-ecosystem/grpc-gateway

To integrate with Fiber, I used the Fiber Adaptor (also pretty straightforward): https://docs.gofiber.io/api/middleware/adaptor

I wonder if they would be happy with something like this: https://github.com/grpc-ecosystem/grpc-gateway

Protobuf is used is massively scaled services like firebase. But you'll still see JSON in streamed realtime services like AWS Kinesis. Hopefully google had a return on investment for creating and using this protocol, but it's not hard to prove that it's far from essential. Out of apparent convenience I use grpc-gateway so I can expose both Protobuf and JSON, but honestly I wouldn't do it again

GRPC is an alternative to rest, rest and GRPC both use the http protocol. But you won’t be able to use fetch to call a GRPC endpoint, you should look into setting up a GRPC proxy within the application(hopping you have access to the source code) grpc-gateway. If you don’t have access you’ll have to create a new container that proxies the calls

(There is an option called google.api.http, that lets you set up a URL that can be used to make HTTP/1 REST requests, which get translated to gRPC calls if you're using grpc-gateway as a proxy in front of your service. That has nothing to do with the requests that are made by gRPC clients and servers themselves.)

Have you looked at https://github.com/grpc-ecosystem/grpc-gateway ?

protoc-gen-grpc-gateway — plugin for creating a gRPC REST API gateway. It allows gRPC endpoints as REST API endpoints and performs the translation from JSON to proto. Basically, you define a gRPC service with some custom annotations and it makes those gRPC methods accessible via REST using JSON requests.