MetaMask iOS SDK

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

See the example iOS dapp and the documentation for setting up the SDK in your iOS dapp for more information.

You can also see the JavaScript SDK repository and the Android SDK repository.

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. Deeplink communication is only available from MetaMask Wallet version 7.21.0

• iOS version 15 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).

  • Swift 5.5 or later.

Get started

1. Install the SDK

CocoaPods

To add the SDK as a CocoaPods dependency to your project, add the following entry to our 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: "0.8.10"
    )
]

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

We have provided a convenient way to make rpc requests without having to first make a connect request. Please refer to Connect With Request for examples. Otherwise you can connect your dapp to MetaMask as follows:

Create dapp metadata

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

Option 1: Deeplink Communication Layer

The SDK supports communication with MetaMask wallet via deeplinking. To configure your dapp to work with deeplink communication you need to add a url scheme in your dapp target's Info setting under URL Types. Alternatively you can add it in your dapp's plist as shown below:

    <key>CFBundleURLTypes</key>
    <array>
        <dict>
            <key>CFBundleTypeRole</key>
            <string>Editor</string>
            <key>CFBundleURLName</key>
            <string>com.dubdapp</string>
            <key>CFBundleURLSchemes</key>
            <array>
                <string>dubdapp</string>
            </array>
        </dict>
    </array>

Then in the AppDelegate's open url method handle deeplinks from the MetaMask wallet

func application(_ app: UIApplication, open url: URL, options: [UIApplication.OpenURLOptionsKey : Any] = [:]) -> Bool {
    if URLComponents(url: url, resolvingAgainstBaseURL: true)?.host == "mmsdk" {
        MetaMaskSDK.sharedInstance?.handleUrl(url)
    } else {
        // handle other deeplinks
    }
    return true
}

And then initialise the SDK, specifying .deeplinking as the transport type, passing the dapp's' scheme you added in the URL Types as the dappScheme. To use the Infura API to make read-only requests, specify your Infura API key using the infuraAPIKey option in SDKOptions. To use your own node (for example, with Hardhat) to make read-only requests, specify your node's chain ID and RPC URL using the readonlyRPCMap option.

@ObservedObject var metamaskSDK = MetaMaskSDK.shared(
    appMetadata,
    transport: .deeplinking(dappScheme: "dubdapp"),
    sdkOptions: SDKOptions(infuraAPIKey: "your-api-key", readonlyRPCMap: ["0x1": "hptts://www.testrpc.com"]) // for read-only RPC calls
)

NOTE

Note that deeplink communication is only available from MetaMask Wallet version 7.21.0.

Option 2: Socket Communication Layer

Alternatively, by default, the dapp communicates with the MetaMask wallet via sockets.

// To use deeplinking as transport layer
@ObservedObject var metamaskSDK = MetaMaskSDK.shared(
    appMetadata,
    transport: .socket,
    sdkOptions: SDKOptions(infuraAPIKey: "your-api-key") // for read-only RPC calls

Then connect the SDK

let connectResult = await 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.enableDebug = false.

4. Call methods

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

We have provided convenience methods for most common rpc calls so that you do not have to manually construct rpc requests. However, if you wish to provide a more fine-grained request not catered for by the convenience methods you can construct a request and then call metamaskSDK.request(EthereumRequest)

Example: Get chain ID

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

let result = await metamaskSDK.getChainId()

Example: Get account balance

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

// Create parameters
let selectedAddress = metamaskSDK.account

// Make request
let accountBalance = await metamaskSDK.getEthBalance(address: selectedAddress, block: "latest")

Example: Send transaction

The following example sends a transaction by calling eth_sendTransaction.

Use convenience method

let selectedAddress = metamaskSDK.account

let result = await metamaskSDK.sendTransaction(
    from: selectedAddress, 
    to: "0x...", // recipient address
    value: "0x....." // amount
    )

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] = [
    "to": "0x...", // receiver address
    "from": account, // sender address
    "value": "0x..." // amount
  ]

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

// 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(
    to: "0x...", // receiver address
    from: account, // sender address
    value: "0x..." // amount
)

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

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

Example: Send chained rpc (batch) requests

Please note that for request batching, the collection of `EthereumRequest<T>` needs to be of the same `<T>` type, i.e all requests use the same `params` type, e.g `[Transaction]`, or `[String]` etc. You can mix the rpc requests e.g a mix of `personal_sign`, eth_signTypedData_v4 etc as long as they share the same params type. 
// Create parameters
let account = metamaskSDK.account

let params1: [String] = [account, "Message 1"]
let params2: [String] = [account, "Message 2"]
let params3: [String] = [account, "Message 3"]

let signRequest1 = EthereumRequest(
    method: .personalSign,
    params: params1
)

let signRequest2 = EthereumRequest(
    method: .personalSign,
    params: params2
)

let signRequest3 = EthereumRequest(
    method: .personalSign,
    params: params3
)

let requestBatch: [EthereumRequest] = [signRequest1, signRequest2, signRequest3]

let result = await metamaskSDK.batchRequest(requestBatch)

5. Connect With Request

Example: Connect with request

We have provided a convenience method that enables you to connect and make any request in one rpc request without having to call connect() first.

let transaction = Transaction(
    to: to,
    from: metamaskSDK.account, // this is initially empty before connection, will be populated with selected address once connected
    value: amount
)

let parameters: [Transaction] = [transaction]

let transactionRequest = EthereumRequest(
    method: .ethSendTransaction,
    params: parameters
)

let transactionResult = metamaskSDK.connectWith(transactionRequest)

Example: Connect with sign

We have further provided a specific convenience method that enables you to connect and make a personal sign rpc request. In this case you do not need to construct a request, you only provide the message to personal sign.

val message = "This is the message to sign"

let connectSignResult = await metamaskSDK.connectAndSign(message: message)

switch connectSignResult {
    case let .success(value):
        // use result
    case let .failure(error):
        // handle error
}