Server Quickstart (Vapor)

This guide shows how to add the Swift AI SDK to a Vapor app and expose a streaming endpoint.

1) Package.swift

5.10

import PackageDescription

let package = Package(
  name: "AIService",
  platforms: [.macOS(.v13)],
  dependencies: [
    .package(url: "https://github.com/vapor/vapor", from: "4.96.0"),
    .package(url: "https://github.com/teunlao/swift-ai-sdk", branch: "main")
  ],
  targets: [
    .executableTarget(
      name: "AIService",
      dependencies: [
        .product(name: "Vapor", package: "vapor"),
        .product(name: "SwiftAISDK", package: "swift-ai-sdk"),
        .product(name: "OpenAIProvider", package: "swift-ai-sdk")
      ]
    )
  ]
)

2) Configure API Key

Set OPENAI_API_KEY in your environment.

3) Streaming route (SSE)

import Vapor
import SwiftAISDK
import OpenAIProvider

func routes(_ app: Application) throws {
  app.get("stream") { req async throws -> Response in
    let stream = try streamText(
      model: openai("gpt-4o"),
      prompt: req.query[String.self, at: "q"] ?? "Hello"
    )

    let sse = makeStreamTextSSEStream(stream.fullStream, includeUsage: false)

    let res = Response(status: .ok)
    res.headers.replaceOrAdd(name: .contentType, value: "text/event-stream")

    // Pipe chunks
    for try await line in sse {
      try await res.body.write(.init(string: "data: \(line)\n\n"))
      try await res.body.flush()
    }
    return res
  }
}

Tip: You can also use pipeTextStreamToResponse with a small adapter that conforms to StreamTextResponseWriter.