Use MetaMask SDK with iOS

Import MetaMask SDK into your native iOS dapp to enable your users to easily connect with their MetaMask Mobile wallet.

Prerequisites

• MetaMask Mobile version 7.6.0 or later installed on your target device (that is, a physical device or emulator). You can install MetaMask Mobile from the App Store or clone and compile MetaMask Mobile from source and build to your target device.

• iOS version 14 or later. The SDK supports ios-arm64 (iOS devices) and ios-arm64-simulator (M1 chip simulators). It currently doesn't support ios-ax86_64-simulator (Intel chip simulators).

Steps

1. Install the SDK

CocoaPods

To add the SDK as a CocoaPods dependency to your project, add the following entry to your Podfile:

pod "metamask-ios-sdk"

Run the following command:

pod install

Swift Package Manager

To add the SDK as a Swift Package Manager (SPM) package to your project, in Xcode, select File > Swift Packages > Add Package Dependency. Enter the URL of the MetaMask iOS SDK repository: https://github.com/MetaMask/metamask-ios-sdk.

Alternatively, you can add the URL directly in your project's package file:

dependencies: [
  .package(
    url: "https://github.com/MetaMask/metamask-ios-sdk",
    from: "0.3.0"
  )
]

2. Import the SDK

Import the SDK by adding the following line to the top of your project file:

import metamask_ios_sdk

3. Connect your dapp

Connect your dapp to MetaMask by adding the following code to your project file:

let appMetadata = AppMetadata(name: "Dub Dapp", url: "https://dubdapp.com")

@ObservedObject var metamaskSDK = MetaMaskSDK.shared(appMetadata)

metamaskSDK.connect()

By default, MetaMask logs three SDK events: connectionRequest, connected, and disconnected. This allows MetaMask to monitor any SDK connection issues. To disable this, set MetaMaskSDK.shared.enableDebug = false or ethereum.enableDebug = false.

4. Call methods

You can now call any JSON-RPC API method using metamaskSDK.request().

Example: Get chain ID

The following example gets the user's chain ID by calling eth_chainId.

let chainIdRequest = EthereumRequest(method: .ethChainId)
let chainId = await metamaskSDK.request(chainIdRequest)

Example: Get account balance

The following example gets the user's account balance by calling eth_getBalance.

// Create parameters.
let account = metamaskSDK.account

let parameters: [String] = [
  // Account to check for balance.
  account,
  // "latest", "earliest", or "pending" (optional)
  "latest"
]

// Create request.
let getBalanceRequest = EthereumRequest(
  method: .ethGetBalance,
  params: parameters
)

// Make request.
let accountBalance = await metamaskSDK.request(getBalanceRequest)

Example: Send transaction

The following example sends a transaction by calling eth_sendTransaction.

Use a dictionary

If your request parameters make up a simple dictionary of string key-value pairs, you can use the dictionary directly. Note that Any or even AnyHashable types aren't supported, since the type must be explicitly known.

// Create parameters.
let account = metamaskSDK.account

let parameters: [String: String] = [
  // Receiver address.
  "to": "0x...",
  // Sender address.
  "from": account,
  // Amount to send.
  "value": "0x..."
]

// Create request.
let transactionRequest = EthereumRequest(
  method: .ethSendTransaction,
  // eth_sendTransaction expects an array parameters object.
  params: [parameters]
)

// Make a transaction request.
let transactionResult = await metamaskSDK.request(transactionRequest)

Use a struct

For more complex parameter representations, define and use a struct that conforms to CodableData, that is, a struct that implements the following requirement:

func socketRepresentation() -> NetworkData

The type can then be represented as a socket packet.

struct Transaction: CodableData {
  let to: String
  let from: String
  let value: String
  let data: String?

  init(to: String, from: String, value: String, data: String? = nil) {
    self.to = to
    self.from = from
    self.value = value
    self.data = data
  }

  func socketRepresentation() -> NetworkData {
    [
      "to": to,
      "from": from,
      "value": value,
      "data": data
    ]
  }
}

// Create parameters.
let account = metamaskSDK.account

let transaction = Transaction(
  // Receiver address.
  to: "0x...",
  // Sender address.
  from: account,
  // Amount.
  value: "0x..."
)

// Create request.
let transactionRequest = EthereumRequest(
  method: .ethSendTransaction,
  // eth_sendTransaction expects an array parameters object.
  params: [transaction]
)

// Make a transaction request.
let result = await metamaskSDK.request(transactionRequest)

Example

See the example iOS dapp in the iOS SDK GitHub repository for more information.