Lean Docs

Link SDK

Link is Lean’s official SDK that leverages the capabilities of modern browsers and mobile clients, such as asynchronous communication, encryption at REST, transit and much more, while giving you an optimised, customizable, conversion-optimized user journey for your users to connect their accounts.

How to integrate

WebiOSAndroid

To integrate Lean’s Link SDK, you first need to add the SDK to your front-end by importing it as follows:

html

<script src="https://cdn.leantech.me/link/sdk/web/latest/Lean.min.js" />

You will then need to include the following div within your body:

html

<div id="lean-link"></div>

This will enable you to call Lean globally in your application.

Available Methods

.connect()

The .connect() method is used to connect a customer to both the Payments and Data API. You can use this method to generate a Payment Source and an Entity with a single customer login.

.link()

The .link method is used to connect accounts with the Data API.

[see reference]

.reconnect()

The .reconnect method is used to reauthenticate a customer account with the Data API.

[see reference]

.createPaymentSource()

The .createPaymentSource method is used to connect a bank account as a payment method to your application in the Payments API.

[see reference]

.updatePaymentSource()

The .updatePaymentSource method is used to authorize an additional payment destination for an existing payment source in the Payments API.

[see reference]

.pay()

The .pay method is used to make a bank to bank transfer from your customer's account to your account in the Payments API.

[see reference]

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javascript

Lean.connect({
  app_token: "2c9a80897169b1dd01716a0339e30003",
  permissions: ["identity", "accounts", "transactions", "balance", "payments"],
  customer_id: "d57a03bc-ef9d-460b-8fa6-3b17e425326c",
  payment_destination_id: "f8d6fe12-5cc3-4df2-82c2-48b4dd6f74a7",
  sandbox: "true",
});

javascript

Lean.link({
  app_token: "2c9a80897169b1dd01716a0339e30003",
  permissions: ["identity", "accounts", "transactions", "balance"],
  customer_id: "d57a03bc-ef9d-460b-8fa6-3b17e425326c",
  sandbox: "true",
});

javascript

Lean.reconnect({
  app_token: "2c9a80897169b1dd01716a0339e30003",
  reconnect_id: "e9521dc4-adc6-4c09-9994-f8b13f28db85",
  sandbox: "true",
});

javascript

Lean.createPaymentSource({
  app_token: "2c9a80897169b1dd01716a0339e30003",
  customer_id: "d57a03bc-ef9d-460b-8fa6-3b17e425326c",
  payment_destination_id: "f8d6fe12-5cc3-4df2-82c2-48b4dd6f74a7",
  sandbox: "true",
});

javascript

Lean.updatePaymentSource({
  app_token: "2c9a80897169b1dd01716a0339e30003",
  customer_id: "d57a03bc-ef9d-460b-8fa6-3b17e425326c",
  payment_source_id: "88d7aefe-aae6-4eb3-a314-6e60e73fda35",
  payment_destination_id: "f8d6fe12-5cc3-4df2-82c2-48b4dd6f74a7",
  sandbox: "true",
});

javascript

Lean.pay({
    app_token: "2c9a80897169b1dd01716a0339e30003",
    payment_intent_id: "452bcde4-5e48-44bb-8f6d-40c5c286466b"
    sandbox: "true"
});

Webhook URL

Results from the Link SDK will be sent to your server via a POST request from Lean made to the Webhook URL in the application settings.

Response

type String

The type of the webhook being received in the format of: [Object type].[action]. When triggered by the Lean.link() call, the type will be entity.created.

message String

Description of the event that has triggered the webhook.

payload Object

The resource which has triggered the webhook.

Upon entity creation, this will be the entity object:

View child attributes

id String

The identifier you will use to reference your customer's bank entity when making API calls.

app_user_id String

For your convenience, we’ll also pass the id your application uses to reference your customer.

permissions Array

The permissions your customer granted you.

bank_details Object

Attributes related to the bank that the entity originates from.

View child attributes

name String

The name of the bank where your user's entity and accounts exist.

bank_identifier String

For use with the /bank endpoint, allows you to query data on the bank related to the entity.

logo_url String

A URL pointing to an image of the bank's logo.

main_color String

The HEX value of the primary color the bank uses for display purposes.

background_color String

The HEX value of the secondary color the bank uses for display purposes.

timestamp DateTime

The time at which the webhook was triggered.

json

// Success Example


{
  "type": "entity.created",
  "message": "An entity object has been created.",
  "payload": {
    "id": "f08fb010-878f-407a-9ac2-a7840fb56185",
    "app_user_id": "00001",
    "permissions": ["transactions", "balance", "identity", "accounts"],
    "bank_details": {
      "name": "Lean Mockbank",
      "identifier": "LEANMB1_SAU",
      "logo": "https://cdn.leantech.me/img/banks/white-lean.png",
      "main_color": "#1beb75",
      "background_color": "#001E26"
    }
  },
  "timestamp": "2020-10-10T17:19:00.059933Z"
}

Callback functions

The Web SDK takes an optional parameter for callback which allows you to recieve events on SDK close, completion or error. The object returned to your callback function is in the following format:

Response

status enum

The end status of the LinkSDK at close.

View status'
StatusReason
SUCCESSThe initated flow was completed successfully
USER_CANCELLEDThe initiated flow was cancelled by the user
ERRORThe SDK or user experienced an error - the details for the error are available in the message and secondary_status.

message string

Further details on the end state. May be null.

last_api_response string

Details on the last response status from the Lean API. May be null.

exit_point enum

The last screen displayed before the user exited the SDK.

View exit points
valuescreen
INITIALThe first screen displayed to users
RECONNECT_INITIALThe first screen displayed to users when using .reconnect()
BANK_SELECTIONThe bank list screen
OPEN_BANKINGOpen banking redirect initiation
CONSENTThe permissions screen
CREDENTIALSThe login detail entry screen
CREDENTIALS_UPDATEThe re-entry form for login details when credentials are outdated
MFAThe OTP entry screen
OPEN_BANKING_ENABLE_PAYMENTSOpen banking redirect initiation for payments
PAYMENT_SOURCESThe screen that lists all a user's payment sources prior to payment initiation
UPDATE_PAYMENT_SOURCEThe update payment source consent screen
PAYMENT_DETAILSThe payment initiation screen
SECURITY_QUESTIONThe security question answer form
MFA_INSTRUCTIONSThe instructions for entering an OTP
UNSUPPORTED_BANK_REQUESTThe unsupported bank list screen
SUCCESSThe success screen
FAILThe failure screen

secondary_status enum

Further details on failures e.g. INVALID_CREDENTIALS. May be null.

View status'

bank object

Details on the bank selected by the user.

View attributes

bank_identifier enum

The Lean identifier for the bank.

is_supported bool

Whether the bank is supported by Lean or not (is false when a user selects a bank through the 'My bank is not listed' button)

javascript

function myCallback(status) {
  console.log(status);
  // insert actions you want to perform on SDK close
}


connectButton.addEventListener("click", function () {
  Lean.link({
    app_token: "YOUR_APP_ID",
    permissions: ["identity", "accounts", "transactions", "balance"],
    customer_id: customerId.value,
    sandbox: "false",
    callback: myCallback,
  });
});

json

{
  "status": "SUCCESS",
  "message": "User successfully connected their account",
  "last_api_response": "SUCCESS",
  "exit_point": "SUCCESS",
  "secondary_status": "SUCCESS",
  "bank": {
    "bank_identifier": "ENBD_UAE",
    "is_supported": true
  }
}

Unsupported banks

Your users can indicate that their bank is not supported. When this happens, the callback from the LinkSDK will contain a false flag in the bank object.

json

{
  "status": "SUCCESS",
  "message": "User successfully connected their account",
  "last_api_response": "SUCCESS",
  "exit_point": "SUCCESS",
  "secondary_status": "SUCCESS",
  "bank": {
    "bank_identifier": "SIB_UAE",
    "is_supported": false
  }
}

Skip Bank List

In some use cases you may want to provide your own UI for the bank selection screen in the LinkSDK. This can be achieved by passing in a bank_identifier during the .link() and .createPaymentSource flows.

You can get a list of available bank_identifiers for your application by making a call to the /banks/ endpoint.

bash

curl -X GET 'https://api.leantech.me/banks/v1/' \
  --header 'lean-app-token: 2c9a80897169b1dd01716a0339e30003'

json

// example response
[
    {
        "id": 13,
        "identifier": "FAB_UAE",
        "name": "First Abu Dhabi Bank",
        "main_color": "#ffffff",
        "background_color": "#00458A",
        "theme": "light",
        "country_code": "UAE",
        "active": true,
        "traits": [
            "user-input-on-login",
            "auth-credentials"
        ],
        "supported_account_types": [
            "CREDIT",
            "SAVINGS",
            "CURRENT"
        ]
    },
    {
        "id": 12,
        "identifier": "ENBD_UAE",
        "name": "Emirates NBD",
        "main_color": "#FDB813",
        "background_color": "#06357A",
        "theme": "light",
        "country_code": "UAE",
        "active": true,
        "traits": [
            "auth-credentials"
        ],
        "supported_account_types": [
            "CREDIT",
            "SAVINGS",
            "CURRENT"
        ]
    }

javascript

Lean.link({
  app_token: "2c9a80897169b1dd01716a0339e30003",
  permissions: ["identity", "accounts", "transactions", "balance"],
  customer_id: "552e8102b3c14401a36ac14fadab94de",
  sandbox: "true",
  bank_identifier: "ENBD_UAE",
});

javascript

Lean.createPaymentSource({
  app_token: "2c9a80897169b1dd01716a0339e30003",
  customer_id: "552e8102b3c14401a36ac14fadab94de",
  sandbox: "true",
  bank_identifier: "ENBD_UAE",
});

Skip Payment Source selection

In Some use cases, you may want to render your own list of Payment Sources - or have business logic around which payment source can be used to make a specific payment. In these cases, you can pass the accounts[n].id parameter from a Customer's Payment Source into the LinkSDK to skip the selection screen within the SDK.

How to get Payment Sources for a Customer

json

// Payment Source - available from /customers/v1/{customer_id}/payment-sources


{
        "id": "0cb405e4-dbda-4420-9421-5202111934cb",
        "customer_id": "79ed9723-f409-4b21-b7b6-8678be94383d",
        "app_id": "40289089716ab818017178bc1cff0005",
        "bank_identifier": "HSBC_UAE",
        "status": "ACTIVE",
        "beneficiary_cool_off_expiry": null,
        "accounts": [
            {
                "id": "ec02035e-bff8-4ada-832e-c3a71105ba48",
                "account_id": "c6d2121b-7e3a-4ce0-9f47-905497a23b2d",
                "account_name": "CURRENT ACCOUNT",
                "account_number": "030-798508-001",
                "iban": "AE870200000030798508001",
                "balance": 465.38,
                "currency": "AED",
                "balance_last_updated": "2021-03-01T17:07:30.172853Z"
            }
        ]
    },

javascript

Lean.pay({
    app_token: "2c9a80897169b1dd01716a0339e30003",
    payment_intent_id: "452bcde4-5e48-44bb-8f6d-40c5c286466b"
    sandbox: "true",
    account_id: "ec02035e-bff8-4ada-832e-c3a71105ba48"
});

Customizing Link SDK

We are progressively releasing customization capabilities to the Link SDK to match its UI with your application branding style. This allows customers to programmatically theme the Link SDK directly from any of the methods.

For more detailed documentation on how best to use the customization feature see our guides.

Customization guide →

Color options

theme_color String

Buttons background color, active input borders, and loading spinners.

button_text_color String

Elements inside any primary button such as the text, icons and the loading spinner. It is useful to boost readability of the button color.

link_color String

CTAs and helpers.

overlay_color String

Overlay containing the Link SDK dialog box.


The following color formats are supported:

ExampleFormat
"#000000"Hex
"#000"Shorthand hex
"#000000FF"Hex with alpha
"rgb(0, 0, 0)"Comma separated RGB
"rgba(0, 0, 0, 0.5)"Comma separated RGB with Alpha
"black"Color name

javascript

Lean.link({
  app_token: "123",
  customer_id: "123",
  permissions: ["identity", "balance", "accounts", "transactions"],
  sandbox: true,
  customization: {
    theme_color: string,
    button_text_color: string,
    link_color: string,
    overlay_color: string,
  },
});

Troubleshooting

Content Security Policy (CSP)

In order to mitigate potential cross-site scripting issues, most modern browsers use a Content Security Policy (CSP). These policies might prevent the SDK from correctly displaying the images captured during the flow or correctly load styles. If CSP is blocking some of the SDK functionalities, make sure you add the following snippet inside the &gt;head&lt; tag of your application.

html

<meta
  http-equiv="Content-Security-Policy"
  content="
    default-src 'self' https://cdn.leantech.me;
    script-src 'self' https://cdn.leantech.me;
    style-src 'self' https://cdn.leantech.me;
    connect-src blob: https://link.sandbox.leantech.me https://link.leantech.me https://ipv4.icanhazip.com https://ipv6.icanhazip.com https://api.ipify.org https://api6.ipify.org https://graphql.contentful.com https://api.segment.io;
    img-src 'self' data: https://images.ctfassets.net http://images.contentful.com https://graphql.contentful.com https://cdn.leantech.me;
    media-src blob:;
    object-src 'self' blob:;
    frame-src 'self' data: blob:;
   "
/>

Next Steps

With the Link SDK installed in your application, you can now get entity_ids for the Data API and create payment sources and charges with the Payment API.

Data API Reference →

Payments API Reference →

© Lean Technologies Ltd. 2022