Getting Started with FastLink 3

All new customers, please reference our FastLink 4 documentation. FastLink 3 documentation is provided for current customers, but we are encouraging customers to upgrade to FastLink 4 to experience the feature enhancements available in the latest release.

FastLink is a responsive application that helps end-users link their accounts to your application. It facilitates linking user accounts and offers intuitive searches for financial institutions, credentials management, multifactor authentication implementation, and error handling. It can also be white-labeled to suit your business needs. By using FastLink you can avoid creating complex user flows of ever-changing login mechanisms of different financial institutions. Once FastLink is launched, the application remains active for 120 minutes and in case of inactivity for 30 minutes.

FastLink Product Flows

Yodlee FastLink has the capability to adapt its user interface depending on the data request made through the API. This allows to invoke the most relevant type of user experience flow based on the data request and use case. The three FastLink product flows or user experience flow that adapts to the requested data are:

  • Aggregation: Aggregate account summary-level information such as masked account number, account type, account balance, and account name. Transactions are also retrieved as part of aggregation.
  • Verification: Retrieve account information required to perform account and ownership verification. The user's account profile information such as full account number, routing number, and account holder name(s) are retrieved for the checking and savings accounts held at the sites after verifying the access to the accounts using credentials. To know more about the account verification use case, refer to Account Verification Quickstart and Use Cases.
  • Aggregation plus Verification: Aggregate account summary-level information and transactions, in addition to other low-level account information such as full account number, routing number, and account holder name(s).

Yodlee provides realistic test data for use in the sandbox environment. You can use the test data to put your app through its paces with a variety of situations close to real world accounts. The sandbox does not support linking to live data (real world accounts), so we simulate this with a set of fictional financial institutions.

Integrating FastLink for Web

FastLink is launched from your web application, and you can easily include the below drop-in JavaScript code in the HTML of your application.
The code contains the parameters and other access details needed for FastLink invocation. It primarily includes two actions that are required to launch and close FastLink using the and fastlink.close() methods, respectively. This script also requires a user-specific accessToken that has to be generated on your server-side for your respective environment using the POST /auth/token API.

<script type='text/javascript' src=''></script>
  <div id="container-fastlink">
    <div style="text-align: center;">
      <input type="submit" id="btn-fastlink" value="Link an Account">
    (function (window) {
      //Open FastLink
      var fastlinkBtn = document.getElementById('btn-fastlink');

      fastlinkBtn.addEventListener('click', function() {{
          fastLinkURL: '<fastlink-launch-url>',
          accessToken: 'Bearer <your-access-token>',
          params: {
            userExperienceFlow : 'Aggregation'
          onSuccess: function (data) {
          onError: function (data) {
          onExit: function (data) {
          onEvent: function (data) {

The method in the above script requires the following parameters:

Parameter Name Description

The FastLink application URL that you can access from your API Dashboard.


The user-specific token that is generated for the user who invokes FastLink.


Specify any of the following user experience flow values in params.userExperienceFlow to invoke the desired flow:

  • Aggregation: Aggregate account summary-level information and transactions.
  • Verification: Aggregate account profile information required to perform user profile verification.
  • Aggregation plus Verification: Aggregate account summary-level information and transactions, along with account profile information.

In the params parameter, you can pass additional parameters to deeplink and request different data combinations apart from the predefined aggregation and verification dataset. To know more, refer to Advanced FastLink Integration.


The FastLink application will invoke the callback functions to update its status back to the host application. The host application must be running on the HTTP/HTTPS protocol to receive these callbacks on the server-side. Following are the available callback functions:

  • onSuccess - The onSuccess method is invoked when an account is successfully aggregated or verified along with its basic information. For more details, refer to the Post Messages section in Advanced FastLink Integration.
  • onError - The onError method is invoked to report errors or failures encountered while aggregating or verifying accounts. For more details, refer to the Post Messages section in Advanced FastLink Integration.
  • onExit - The onExit method is called to report when the FastLink application is closed by user-initiated actions.
  • onEvent - The onEvent method is called to notify intermittent status messages to the host application.

Close FastLink

Close the FastLink application by calling the fastlink.close() method:


For more things you can do with FastLink, refer to Advanced FastLink Integration.
To modify the strings, CSS styling, and FastLink features, refer to FastLink 3 Configuration Guide.

Integrating Web Application to Mobile

In Web implementation of FastLink Open Banking flow, opening the financial institution’s OAUTH site to get the user’s consent using the JS method may not work in native WebView. Either the WebView blocks the different domain URL that FastLink tries to load, or the financial institution’s site may not load in the child environment due to security reasons.

To integrate your web application in mobile, which has already integrated FastLink using drop-in JS or iframe, follow the below steps:

  1. Pass isIFrameMounted param as true. For example:
                userExperienceFlow :'Aggregation',
    On passing this param, FastLink will send the external URL as a post message instead of opening the financial institution’s site.
  2. Pass this post message to the native app and open an external browser.
  3. Use intentURl to get control back from the financial institution's site to the native app or use a standard redirection to ydl://backtoframework.

To know how to open a new window and get control back, refer to the respective mobile platform integration pages in the next section.

FastLink integrates easily into mobile platforms using a WebView. The Simplified Mobile Integration key should be enabled in the FastLink 3.0 configuration tool for ease of integration. For more information, refer to the Global section in the FastLink 3.0 Configuration Tool Guide page.