On iOS

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The Clover Connector iOS SDK provides an interface that enables your point-of-sale (POS) software to interact with Clover’s customer-facing payment devices.

This tutorial will guide you through the process of connecting to your Clover device, initiating a Sale request, and handling the response to your Sale request. It covers the current version of the SDK (v4.0).

Platform-specific prerequisites

In addition to the prerequisites in Use Clover Connector, this tutorial assumes you have already:

  • Installed the Secure Network Pay Display app (currently available for Clover Flex, Clover Mini, and Clover Mobile)
  • Installed the appropriate IDE on your computer. The iOS SDK requires:

Your Podfile entry should look like this:

pod 'Starscream', :git => 'https://github.com/clover/Starscream.git', :branch => 'queuePriority'
pod 'CloverConnector', :git => 'https://github.com/clover/remote-pay-ios.git', :tag => '3.0.2'

post_install do |installer|
    ['CloverConnector'].each do |targetName|
        targets = installer.pods_project.targets.select { |target| target.name == targetName }
        target = targets[0]
        target.build_configurations.each do |config|
            config.build_settings['SWIFT_VERSION'] = '4.0'


The iOS SDK currently supports network tethering via WebSockets only.

Configure a connection

To connect your iOS device to the Clover device, complete the following steps to pair the two devices.

  1. Connect your POS to the Clover device. The Clover device sends a pairing code to the POS.
  2. Enter the code your POS received on the Clover device.

The Clover device will send a pairingAuthToken to the POS. The POS uses the pairingAuthToken for the next connection, streamlining the pairing process.

The pairingAuthToken is single-use. Clover will expire the original pairingAuthToken and send a new one to the POS for each connection.



To create a secure connection:

  1. Install the Clover Device Server Root CA certificate on the iOS device. The certificate is hosted at https://sandbox.dev.clover.com/v2/device_ca_certificate.der. Once you install the certificate, you can find it at Settings > General > Profile > Clover Device Server Root CA. Confirm that the certificate is verified.
  2. Manually trust the installed certificate at Settings > General > About > Certificate Trust Settings. Under ENABLE FULL TRUST FOR ROOT CERTIFICATES, enable trust for the installed certificate.
/// To connect over a network, you will need a PairingDeviceConfiguration
/// class to handle pairing callbacks from the Clover device
        class ExamplePairingDeviceConfig : PairingDeviceConfiguration {
            @objc private func onPairingCode(pairingCode: String) {
                // present pairingCode to the user to be
                // entered on the Clover Device
            @objc private func onPairingSuccess(authToken: String) {
                // The authToken can be used for the next connection
                // WebSocketDeviceConfiguration (see pairingAuthToken below)

        let pdc = ExamplePairingDeviceConfig()
        // ws vs wss must match Network Pay Display setting
        // wss requires Clover root CA
        let endpoint = "ws://" 
        // Network Pay Display must be installed and configured to allow 
        // insecure connections for the above configuration

        // Create a WebSocketDeviceConfiguration with the appropriate
        // remoteApplicationID (see above), POS name, and POS serial number
        let configuration = WebSocketDeviceConfiguration(endpoint: endpoint,
        // remoteApplicationID, posName and 
        // posSerial are associated with
        // pairingAuthToken
        remoteApplicationID: "SWDEFOTWBD7XT.9MGLGMDLSYWTV", 
        posName: "Aisle 2",
        posSerial: "ABC123",
        pairingAuthToken: nil,
        // use token from onPairingSuccess callback
        pairingDeviceConfiguration: pdc)

Create a Clover Connector

Create a Clover Connector and pass in the configuration from the previous step.

/// Use instance of WebSocketDeviceConfiguration
cloverConnector = CloverConnector(config: configuration)

Add a listener to the Clover Connector

  1. Define an ICloverConnectorListener that will listen for callbacks when transactions finish and other events occur. Include the connection status methods that will be called.
  • OnDeviceDisconnected() – The Clover device is not available.
  • OnDeviceConnected() – The Clover device is connected, but not available to process requests.
  • OnDeviceReady() – The device is connected and available to process requests. It will automatically pass in a MerchantInfo object with information about the device, merchant, and some potential merchant payment configuration data, such as supportsAuths or supportsVaultCards.
// Create an implementation of ICloverConnectorListener
	class ExampleCloverConnectorListener : DefaultCloverConnectorListener {
  	override func onDeviceDisconnected() {
    	// Disconnected
          	override func onDeviceConnected() {
            	// Connected, but not available to process requests
            override func onDeviceReady(merchantInfo: MerchantInfo) {
              // Connected and available to process requests
  1. Add the listener to the Clover Connector.
// Add an instance of an ICloverConnectorListener
let ccl = ExampleCloverConnectorListener(cloverConnector: cloverConnector)

Initialize the connection

Initialize the connection to start communication with the Clover device. Note that you must do this before calling any other methods (other than those that add or remove listeners).


Display a message on the Clover device

Send a test message to the Clover device.

cloverConnector.showMessage("Welcome to Clover Connector!")

Now that you’ve connected to the Clover device and sent a successful test message, you’re ready to start making requests.

Initiate a sale from your POS software

To make a Sale() request:

  1. Define how to handle the SaleResponse in your ICloverConnectorListener first. The truncated code below provides a generalized overview of the methods you’ll need to use to get a response to your request for a Sale. A detailed interpretation of the SaleResponse appears in the Handle the result of a Sale transaction section section.
public class ExampleCloverConnectorListener:DefaultCloverConnectorListener {
      public override func onSaleResponse(_ response:SaleResponse){
            // check response for success and process accordingly
            // see the ‘Handling the Result of a Sale Transaction’ section below for more detail
      public override func onConfirmPaymentRequest(){
            // must accept or reject the payment using the ICloverConnector
            // see the ‘Handling the Result of a Sale Transaction’ section below for more detail
      public override func onVerifySignatureRequest(_ request:VerifySignatureRequest) {
            // must accept or reject the signature using the ICloverConnector
            // see the ‘Handling the Result of a Sale Transaction’ section below for more detail 
  1. Create a SaleRequest and call the Sale() method.
/// hold the pendingPaymentId to track the payment within Clover
let uuid = NSUUID().uuidString as NSString
let pendingPaymentId = uuid.replacingOccurrences(of: "-", with: "")
let saleRequest = SaleRequest(amount: 2250, externalId: pendingPaymentId)



The code snippets in this tutorial are not feature-rich. For the best way to implement the SDK in production, see the Example iOS POS.

Once you call the Sale() method, Clover will contact the payment gateway and return information about the result of the transaction to your POS.

Handle the result of a sale transaction

After Clover has finished processing the Sale transaction request, OnSaleResponse() will be called. Transaction responses have a boolean Success property, as well as an enum Result property that provides information on the success flag.

If the transaction is successful, the response will also have the Payment object, which may contain the full or partial amount of the Sale request.



A Sale transaction may come back as a tip-adjustable Auth, depending on the payment gateway. The SaleResponse includes a boolean isSale variable that indicates whether the Sale is final, or will be finalized during closeout.

class ExampleCloverConnectorListener:DefaultCloverConnectorListener { 
      override func onSaleResponse(response: SaleResponse) {
          if response.success {
              if let payment = response.payment {
                  if pendingPaymentId == payment.externalPaymentId {
                      // it is the expected payment
                      debugPrint("Got the payment for \(payment.amount ?? -1)")
                  } else {
                      debugPrint("Got a response, but not for the expected payment")
              } else {
                  debugPrint("Something went wrong...No payment found!")
          } else {
              debugPrint("Payment failed: \(response.reason):\(response.message)")
          cloverConnector?.dispose() /// if done using the connector, dispose of it
      // a sale may require payment confirmation requests from the Clover device
      override func onConfirmPaymentRequest(request: ConfirmPaymentRequest) {
          // by default, Clover will just accept the payment
          if let payment = request.payment {
          } else {
              debugPrint("Payment is nil in ConfirmPaymentRequest")
      // a sale may require signature verification requests from the Clover device
      override func onVerifySignatureRequest(signatureVerifyRequest: VerifySignatureRequest)       
          // by default, Clover will just accept the signature

Sale transaction errors

OnSaleResponse() also returns one of the following codes.

  • SUCCESS – The call succeeded and was successfully queued or processed.
  • FAIL – The call failed due to an incorrect value that was passed in, an invalid card, insufficient funds, or another reason.
  • UNSUPPORTED – The current merchant configuration doesn’t support the capability.
  • CANCEL – The merchant or customer has pressed the Cancel or Back button on the Clover device.
  • ERROR – An error that wasn’t expected or handled appropriately occurred. This code is returned when the SDK encounters one of the following problems:
  • Device Connection Error – The Clover device is not connected.
  • Request Validation Error – The request that was passed in for processing is empty.
  • Request Validation Error – The request ExternalId cannot be null or blank.
  • Request Validation Error – The request amount cannot be zero.
  • Request Validation Error – The request tip amount cannot be less than zero.
  • Merchant Configuration Validation Error – Not offered by the merchant-configured gateway.

Test your app

Test your app using the Test card numbers for declines and partial transactions.

For information, see Test region-based payment flows page.

Additional resources