Resty is a networking μframework built on Apple's Combine asynchronous streams framework. It provides a simple, composable, protocol-oriented way to structure wrappers around simple REST APIs.

To wrap an API, conform to the API protocol, add the baseURL for your service, and write Publisher returning functions. Conforming to the API protocol gives you access to the five HTTP verb methods (get(path:), post(path:), put(path:), patch(path:), delete(path:)), to which you can declaratively add request options and get a publisher from, on which you can use all the functional declarative operators that come with Publisher.

import Resty

struct SwiftForums: API {
    let baseURL = URL(string: "https://forums.swift.org")!
    lazy var decoder: JSONDecoder = {
        var decoder = JSONDecoder()
        decoder.keyDecodingStrategy = .convertFromSnakeCase
        return decoder
    }()
    
    func search(term: String, includeBlurbs blurbs: Bool = false) -> AnyPublisher<SearchResult, Error> {
        get(path: "/search")
            .queryItems(["q": term, "include_blurbs": "\(blurbs)"])
            .publisher()
    }
    
    func latestPosts() -> AnyPublisher<[LatestPost], Error> {
        struct LatestPosts: Decodable {
            let latestPosts: [LatestPost]
        }
        
        return get(path: "/posts.json")
            .publisher()
            .decode(type: LatestPosts.self, decoder: decoder)
            .map(\.latestPosts)
            .eraseToAnyPublisher()
    }
}

From here, you'll write a method for each endpoint you need from the API and they will each return an AnyPublisher<Output, Failure>, with the Output being the type of the response you recieve, or Void, if no response. From there you can use your API's Publishers in your app, binding them to UI controls in viewDidLoad() for UIKit or assigning them to @Published properties on your SwiftUI ViewModel.