SDK Integration

zkKYC SDK - Simply execute KYC progress using the RedirectURL as the src-attribute value for the iFrame.

Use Case

To reduce the development cost for the project side, the project can use zkKYC capability by simply accessing the link. Users can achieve full KYC capability on the web/H5, reducing the possibility of user churn by minimizing the need to navigate to another page.

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zkMe-Widget KYC Process

Step 1: Enter the service authorization Widget page, the user confirms and goes to the next step

Step 2: E-mail verification login

Step 3: Verify the SBT to confirm that it is authenticated

Step 4: Depending on the KYC configuration of the project, determine whether the user needs to undergo different verification processes.

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Interaction Instructions

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Integration via NPM

You can refer to @zkmelabs/widget and please make sure to use the latest version.

Installation

pnpm add @zkmelabs/widget

# or
yarn add @zkmelabs/widget

# or
npm install @zkmelabs/widget

Getting Started

Step 1. Import styles

import '@zkmelabs/widget/dist/style.css'

Step 2. Create a new ZkMeWidget instance

Cross-chain

import { ZkMeWidget, type Provider } from '@zkmelabs/widget'

const provider: Provider = {
  async getAccessToken() {
    // -------------------------TODO-------------------------
    // Request a new token from your backend service and return it to the widget.
    // For the access token, see docs.zk.me/zkme-dochub/zkkyc-compliance-suite/zkkyc-integration-guide/sdk-integration#how-to-generate-an-access-token-with-api_key
    // ------------------------------------------------------
    return fetchNewToken()
  },

  async getUserAccounts() {
    // -------------------------TODO-------------------------
    // If your project is a Dapp,
    // you need to return the user's connected wallet address.
    const userConnectedAddress = await connect()
    return [userConnectedAddress]

    // If not,
    // you should return the user's e-mail address, phone number or any other unique identifier.
    //
    // return ['email address']
    // or
    // return ['phone number']
    // or
    // return ['unique identifier']
    // ------------------------------------------------------
  },

}

const zkMeWidget = new ZkMeWidget(
  // -------------------------TODO-------------------------
  appId, // This parameter means the same thing as "mchNo"
  'YourDappName',
  '0x89',
  provider,
  {
      lv: 'zkKYC'
      // For other options, please refer to the table below
  }
  // ------------------------------------------------------
)

On-chain Mint / On-chain Transactional

import { ZkMeWidget, type Provider } from '@zkmelabs/widget'

const provider: Provider = {
  async getAccessToken() {
    // -------------------------TODO-------------------------
    // Request a new token from your backend service and return it to the widget.
    // For the access token, see docs.zk.me/zkme-dochub/zkkyc-compliance-suite/zkkyc-integration-guide/sdk-integration#exchanging-api_key-for-access-token
    // ------------------------------------------------------
    return fetchNewToken()
  },

  async getUserAccounts() {
    // -------------------------TODO-------------------------
    // If your project is a Dapp,
    // you need to return the user's connected wallet address.
    const userConnectedAddress = await connect()
    return [userConnectedAddress]

    // If not,
    // you should return the user's e-mail address, phone number or any other unique identifier.
    //
    // return ['email address']
    // or
    // return ['phone number']
    // or
    // return ['unique identifier']
    // ------------------------------------------------------
  },

  // -------------------------TODO-------------------------
  // According to which blockchain your project is integrated with,
  // choose and implement the corresponding methods as shown below.

  // EVM
  async delegateTransaction(tx) {
    const txResponse = await signer.sendTransaction(tx)
    return txResponse.hash
  },
  // Cosmos
  async delegateCosmosTransaction(tx) {
    const txResponse = await signingCosmWasmClient.execute(
      tx.senderAddress,
      tx.contractAddress,
      tx.msg,
      'auto'
    )
    return txResponse.transactionHash
  },
  // Aptos
  async delegateAptosTransaction(tx) {
    const txResponse = await aptos.signAndSubmitTransaction(tx)
    return txResponse.hash
  },
  // ...
  // See the Provider interface definition for more details on other chains.
  // ------------------------------------------------------
}


const zkMeWidget = new ZkMeWidget(
  // -------------------------TODO-------------------------
  appId, // This parameter means the same thing as "mchNo"
  'YourDappName',
  chainId,
  provider,
  {
      lv: 'zkKYC'
      // For other options, please refer to the table below
  }
  // ------------------------------------------------------
)

NOTE: The specific configuration for the "option" parameter is shown in the table below

Param	Type	Description
options.lv	VerificationLevel?	"zkKYC" or "MeID", default "zkKYC"
options.programNo	string?	The param can be found in Dashboard and please make sure the program is enabled. The SDK will take the number of the first activated program as the default value if this parameter is not provided in the code.
options.theme	Theme?	"auto", "light" or "dark", default "auto". This option must match the 'Set your color mode' settings in the Dashboard. For widget UI customization, please refer to: Widget UI Design.

Step 3. Listen to the kycFinished widget events to detect when the user has completed the zkKYC process.

async function handleFinished(results) {
  const { isGrant, associatedAccount } = results

  if (
    isGrant &&
    associatedAccount === userConnectedAddress.toLowerCase()
  ) {
    // -------------------------TODO-------------------------
    // Prompts the user that zkKYC verification has been completed
    // ------------------------------------------------------
  }
}

zkMeWidget.on('kycFinished', handleFinished)

Step 4. Launch the zkMe widget and it will be displayed in the center of your webpage.

// This is the code to launch our widget on your page
button.addEventListener('click', () => {
  zkMeWidget.launch()
})

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Helper functions

verifyKycWithZkMeServices()

Before launching the widget, you should check the zkKYC status of the user and launch the widget when the check result is false.

import { verifyKycWithZkMeServices } from '@zkmelabs/widget'

// zkKYC
const { isGrant } = await verifyKycWithZkMeServices(
  appId,
  userAccount,
  // Optional configurations are detailed in the table below
  options
)

Param	Type	Description
appId	string	This parameter means the same thing as "mchNo"
userAccount	string	Same value as in provider.getUserAccounts
options.programNo	string?	The param can be found in Dashboard and please make sure the program is enabled. The SDK will take the number of the first activated program as the default value if this parameter is not provided in the code.

If the level of your Dashboard account is not Cross-Chain, then you can also query users' zkKYC status from zkMe Verify & Certify Smart Contract here.

How to Generate an Access Token with API_KEY

To use your API_KEY to obtain an accessToken, you will need to make a specific HTTP request. Here's how you can do it:

a. Endpoint: Send a POST request to the token exchange endpoint.

POST https://nest-api.zk.me/api/token/get

Please remember to modify the Content-Type in the request header to application/json. Failing to do so might result in a Parameter Error response.

b. Request Body:

Parameter Name	Required	Type	Desc
apiKey	True	string	The API_KEY provided by zkMe.
appId	True	string	A unique identifier (mchNo) to DApp provided by zkMe.
apiModePermission	True	number	0-email login (Only support email login)
lv	True	number	1-zkKYC 2-MeID

API_KEYcan be found in the Configuration section of the Integration on the zkMe Dashboard.

c. Response

Success

{
    "code": 80000000,
    "data": {
        "accessToken": "8641259808779c53de65c3698e42b402b112cfe3856202189c37eae9f0b23babbcc1429ea9adcb52283dca4dab024a640651f855d8c78c7bde308f721a6e0cb80d51dab7c775ebfe0ae74eb9ab02f503094a9b2a2e2aeabf70e03a0cac9773a93dba743ca0dc3fa4af77375351bc48f76515d72dbee3a8bd5c034e6ffb94bd97"
    },
    "msg": "success",
    "timestamp": 1691732474552
}

Exception (AppId and API_KEY not matched)

{
    "code": 81000014,
    "data": null,
    "msg": "AppID and API Key do not match. Access token generation failed",
    "timestamp": 1691732568774
}

Exception (Parameter Error)

{
    "code": 80000002,
    "data": null,
    "msg": "parameter error",
    "timestamp": 1691732593484
}

Exception (System Error)

{
    "code": 80000001,
    "data": null,
    "msg": "system error",
    "timestamp": 1691732593484
}

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ZkMeWidget instance methods

launch()

Launch the zkMe widget and it will be displayed in the center of your webpage.

launch(): void

on()

Listen to zkMe widget events.

on(event: 'kycFinished', callback: KycFinishedHook): void;
on(event: 'close', callback: () => void): void;

switchChain()

If your DApp integrates multiple chains, use this method to synchronize the new chain to the zkMe widget when the user switches chains in your DApp.

switchChain(chainId: string): void

hide()

Hide the zkMe widget.

hide(): void

destroy()

Remove the message event listener registered by the zkMe widget from the window and destroy the DOM node.

destroy(): void

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Common Response & Exceptions

Success

If the user has passed the KYC verification and the user’s SBT could be accessed by your project, the following interface will be seen. Meanwhile, there will be a message with KYC results sent to your DApp.

Camera Permission Denied Error

The following screen will be displayed for possible issues such as the user denying browser camera access or not having a camera on the device.

OCR Scan Error

The following screen will be displayed when an exception occurs during the OCR process.

Face Recognition Error

The following screen will be displayed for possible problems such as eyes closed detected, art mask detected etc.

Face Mismatch Error

The following screen will be displayed when the face could not match the uploaded ID.

Faceprint Mismatch Error

The following screen will be displayed for the possible problem that the fully homomorphically encrypted faceprint does not match the one associated with this MeID.

Faceprint Recognition Server Error

The following screen will be displayed when something goes wrong on the faceprint recognition server.

Unknown Error

The following screen will be displayed when something goes wrong not listed above.