---
title: modern-swift-dev/roundtrip-swift
framework: Swift Package Catalog
role: article
path: packages/modern-swift-dev/roundtrip-swift
---

# modern-swift-dev/roundtrip-swift

RoundTrip provides HTTP request construction and async URLSession operations for Apple platforms. RoundTripREST adds a client for APIs with a shared base URL, default headers, response validation, and JSON decoding.

## Platform support

RoundTrip supports iOS 18, macOS 15, tvOS 18, watchOS 11, and visionOS 2. Linux is not supported.

## Install

Add RoundTrip to a Swift Package Manager manifest:

```swift dependencies: [     .package(         url: "https://github.com/modern-swift-dev/roundtrip-swift.git",         from: "1.0.0"     ) ] ```

Add one or both products to the target that uses them:

```swift .product(name: "RoundTrip", package: "roundtrip-swift"), .product(name: "RoundTripREST", package: "roundtrip-swift") ```

For local development against a checkout, use a path dependency instead:

```swift .package(path: "../roundtrip-swift") ```

## Async request

```swift import Foundation import RoundTrip

struct User: Decodable {     let id: Int     let name: String }

let request = URLRequestBuilder(string: "https://example.com/users/42")!     .setMethod(.get)

let client = HttpClient() let response = try await client.execute(request: request) try response.checkForStatusCodeValidity(validStatusCode: [200])

guard let user = response.payloadAs(User.self) else {     throw ApiError.responseDecodingFailed(response.data, ApiError.emptyResponseBody) } print(user.name) ```

## REST request

```swift import Combine import Foundation import RoundTrip import RoundTripREST

struct APIBaseURL: BaseURLProvider {     let baseURL = URL(string: "https://example.com") }

struct NoAPIKey: ApiKeyProvider {     var apiKey: String? { get async { nil } } }

struct UserRequest: URLRequestConvertible {     let id: Int

func buildRequest(baseUrl: URL?, encoder: JSONEncoder) throws -> URLRequest {         guard let baseUrl else { throw ApiError.invalidURL }         return URLRequest(url: baseUrl.appending(path: "users/\(id)"))     } }

struct User: Decodable {     let id: Int     let name: String }

let rest = RestClient(     baseURLProvider: APIBaseURL(),     apiKeyProvider: NoAPIKey(),     service: NetworkService(),     headerProvider: nil,     errorSubject: PassthroughSubject<ApiError, Never>() ) let result: ApiOperationResult<User> = try await rest.execute(request: UserRequest(id: 42)) print(result.value.name) ```

## Documentation

The [central documentation repository](https://github.com/modern-swift-dev/docs) owns Astro, the shared theme, and website/API generation. It builds from `main` daily and on manual runs. Edit page Markdown in `Documentation/Site/` and keep DocC catalogs beside the module sources. See the [docs README](https://github.com/modern-swift-dev/docs/blob/main/README.md) for local build and preview commands. Do not commit generated HTML to this repository.

Read the [RoundTrip documentation](https://modern-swift-dev.github.io/docs/roundtrip-swift/) on GitHub Pages. Start with the [installation and request guide](https://modern-swift-dev.github.io/docs/roundtrip-swift/documentation/getting-started/), then use the generated DocC references for [RoundTrip](https://modern-swift-dev.github.io/docs/roundtrip-swift/api/roundtrip/documentation/roundtrip/) and [RoundTripREST](https://modern-swift-dev.github.io/docs/roundtrip-swift/api/roundtrip-rest/).

## Contributing

See [CONTRIBUTING.md](CONTRIBUTING.md). RoundTrip is available under the MIT license. See [LICENSE](LICENSE).

## Package Metadata

Repository: modern-swift-dev/roundtrip-swift

Default branch: main

README: README.md