A sample application can be found on Github.

As Trailblazer provides Operation to encapsulate the business logic, and representers for rendering and parsing documents, Grape ends up being leveraged as a routing layer that dispatches to operations.

module API
  class Application < Grape::API
    format :json

    version :v1 do
      get("posts")  { run!(Post::Show, request) }
      post("posts") { run!(Post::Create, request) }
    end
  end
end

Routing

Using Grape’s popular routing DSL, routes point straight to operations and pass in the request body as a hash.

Validation

Grape comes with built-in parameter validation and deserialization mechanics. Both are, nevertheless, very limited and a subset of what Trailblazer’s contract and representer provide. With Trailblazer, there’s no need to use those parts of Grape - even though you could if you want.