IBKit is open source Interactive Brokers API library written in Swift. It allows you to automate trades, retrieve market data and monitor positions and orders. Offering both live and paper trading capabilities, it can be used as an algo trading platform or as an backtesting datasource. In latter case you need to write your own portfolio accounting and performance measurement methods.

The software is not an official API and is not affiliated or related with Interactive Brokers.

The current version should conform with IB API version 10.24. It is the aim to update the software with to MacOS major releases and include also better bites from TWS API.

• Common features seems to work fine but complex orders may generate errors.
• FA Accounts are not currently supported

• IB Gateway.
• macOS 12+
• Swift 5.5+
• XCode 13+

• Launch IB Gateway, select IB Api as interface and use your live or paper trading credentials to log in.
• To prevent IB Gateway/TWS to close application on your specified time, you need to select “Restart” option instead of “Auto logoff” under Configuration>Lock and Exit menu. IB maintains its servers on Saturday early mornings (GMT) and the service is disrupted for a few hours. They also restart their servers on each morning so your gateway or workstation will be disconnected for a minute or two.
• Pay attention to your Master Client ID, host and port as you will need them when initiating new client. You find these values under Configuration>Settings>API>Settings menu.
• Select UTC format for sending instrument-specific attributes
• If you want to submit orders, you shall also uncheck Read Only API from Configuration>Settings>API>Settings menu.

Create a new Xcode project and navigate to File > Swift Packages > Add Package Dependency. Enter the url https://github.com/stensoosaar/IBKit and tap Next. Choose the main branch, and on the next screen, check off the packages as needed.

While the api calls closely resemble IB's own API, the responses are provided by using dedicated data publishers for market, account and system events.

	var subscriptions: [AnyCancellable] = []

	client.marketEventFeed
		.sink { event in 
			handle event
		}
		.store(in: &subscriptions)

	do {
		let requestID = client.getNextID()
		let interval = DateInterval.lookback(10, unit: .minute, until: .distantFuture)
		try client.requestPriceHistory(requestID, contract: contract, barSize: IBBarSize.day, barSource: IBBarSource.bidAsk, lookback: interval)
	} catch {
		print(error.localizedDescription)
	}

Most response messages are stripped down from request context (e.g., bar size or source), and you need to pair requests and responses using a unique requestID. One way to achieve that is to create your own custom publisher and map the data against your own data model.

class SimulatedBroker{

   var api: IBClient

   func priceHistoryPublisher(_ interval: DateInterval, size: IBBarSize, contract: IBContract, extendedSession: Bool = false) throws -> AnyPublisher<AnyPriceUpdate, CustomAPIError>{
   		
   	let requestID = api.nextRequestID
   	let source: IBBarSource = [.cfd, .forex, .crypto].contains{$0 == contract.securitiesType} ? .midpoint : .trades
   	let request = IBPriceHistoryRequest(requestID: requestID, contract: contract, size: size, source: source, lookback: interval, extendedTrading: extendedSession)
   	try api.send(request: request)
   	
   	return AnyPublisher(self.api.eventFeed
   		.setFailureType(to: CustomAPIError.self)
   		.compactMap { $0 as? IBIndexedEvent }
   		.filter { $0.requestID == requestID }
   		.tryMap{ response -> (any AnyPriceUpdate) in
   			switch response {
   			   // handle response / error here 
   			}
   		.mapError { $0 as! CustomAPIError }
   		.eraseToAnyPublisher()
   	)
   		
   }
}


let broker = SimulatedBroker(id: 0)
var subscriptions: [AnyCancellable] = []
broker.api.connect()

do{
   let contract = IBContract.future(localSymbol: "MESM4", currency: "USD")
   let interval = DateInterval.lookback(10, unit: .minute, until: .distantFuture)
   try broker.priceHistoryPublisher(interval, size: .minute, contract: contract)
   	.sink { completion in
   		print(completion)
   	} receiveValue: { response in
   		print(respinse)
   	}
   	.store(in: &subscriptions)
} catch{
   print(error.localizedDescription)
}

See also included playground pages.