Add Knot to your app

Knot and Plaid have partnered to offer a seamless and secure solution for managing card-on-file information across a vast network of merchants. Knot's CardSwitcher™ effortlessly automates the process of adding or updating a cardholder’s credit or debit card at almost any merchant, ensuring that your card remains top-of-wallet. Knot Customers can use Plaid’s transaction data to suggest hyper relevant CardSwitches that are personalized based on a cardholder’s transaction history.

Utilizing Knot’s CardSwitcher™, card issuers can now automate the entire lifecycle of a cardholder. From initial issuance, through card replacements, and card expirations, all while remaining top-of-wallet. The integration with Plaid further enhances this process by providing Knot customers with transaction history that allows cardholders to receive personalized CardSwitcher suggestions.

You'll first want to familiarize yourself with Plaid Link, a drop-in client-side integration for the Plaid API that handles input validation, error handling, and multi-factor authentication. You will also need to have a verified Knot account to add a bank funding source. Your customers will use Link to authenticate with their financial institution and select the bank account they wish to connect. From there, you'll receive a Plaid access_token and a Knot processor_token, which allows you to quickly and securely retrieve the user's financial data via Knot's API. Utilizing Plaid + Knot enables a seamless workflow for connecting external financial accounts to Knot.

You'll need accounts at both Plaid and Knot in order to use the Plaid + Knot integration. You'll also need to enable your Plaid account for the Knot integration.

First, you will need to work with the Knot team to sign up for a Knot account, if you do not already have one.

Next, verify that your Plaid account is enabled for the integration. If you do not have a Plaid account, create one.

To enable your Plaid account for the integration, go to the Integrations section of the account dashboard. If the integration is off, simply click the 'Enable' button for Knot to enable the integration.

You'll need to complete your Plaid Application Profile in the Dashboard, which involves filling out basic information about your app, such as your company name and website. This step helps your end-users learn more how your product uses their bank information and is also required for connecting to some banks.

Finally, you'll need to go to the Link customization UI and pick the use cases that you will be using Knot to power, so that Plaid can request the appropriate authorization and consent from your end users. If you have any questions, contact Knot.

In order to integrate with Plaid Link, you will first need to create a link_token. A link_token is a short-lived, one-time use token that is used to authenticate your app with Link. To create one, make a /link/token/create request with your client_id, secret, and a few other required parameters from your app server. For a full list of link_token configurations, see /link/token/create.

To see your client_id and secret, visit the Plaid Dashboard.

1const request: LinkTokenCreateRequest = {
2  loading_sample: true
3};
4try {
5  const response = await plaidClient.linkTokenCreate(request);
6  const linkToken = response.data.link_token;
7} catch (error) {
8  // handle error
9}

Once you have a link_token, all it takes is a few lines of client-side JavaScript to launch Link. Then, in the onSuccess callback, you can call a simple server-side handler to exchange the Link public_token for a Plaid access_token and a Knot processor_token.

1<button id="linkButton">Open Link - Institution Select</button>
2<script src="https://cdn.plaid.com/link/v2/stable/link-initialize.js"></script>
3<script>
4  (async function(){
5    var linkHandler = Plaid.create({
6      // Make a request to your server to fetch a new link_token.
7      token: (await $.post('/create_link_token')).link_token,
8      onSuccess: function(public_token, metadata) {
9        // The onSuccess function is called when the user has successfully
10        // authenticated and selected an account to use.
11        //
12        // When called, you will send the public_token and the selected accounts,
13        // metadata.accounts, to your backend app server.
14        sendDataToBackendServer({
15           public_token: public_token,
16           accounts: metadata.accounts
17        });
18      },
19      onExit: function(err, metadata) {
20        // The user exited the Link flow.
21        if (err != null) {
22            // The user encountered a Plaid API error prior to exiting.
23        }
24        // metadata contains information about the institution
25        // that the user selected and the most recent API request IDs.
26        // Storing this information can be helpful for support.
27      },
28    });
29  })();
30
31  // Trigger the authentication view
32  document.getElementById('linkButton').onclick = function() {
33    // Link will automatically detect the institution ID
34    // associated with the public token and present the
35    // credential view to your user.
36    linkHandler.open();
37  };
38</script>

See the Link parameter reference for complete documentation on possible configurations.

Plaid.create accepts one argument, a configuration Object, and returns an Object with three functions, open, exit, and destroy. Calling open will display the "Institution Select" view, calling exit will close Link, and calling destroy will clean up the iframe.

The Link module handles the entire onboarding flow securely and quickly, but does not actually retrieve account data for a user. Instead, the Link module returns a public_token and an accounts array, which is a property on the metadata object, via the onSuccess callback. Exchange this public_token for a Plaid access_token using the /item/public_token/exchange API endpoint.

The accounts array will contain information about bank accounts associated with the credentials entered by the user, and may contain multiple accounts if the user has more than one bank account at the institution. The `accounts` array will contain information about bank accounts associated with the credentials entered by the user, and may contain multiple accounts if the user has more than one bank account at the institution. In most cases, you will want your users to connect all of their accounts so that they can be tracked in Knot.

Once you have identified the account you will use, you will send the access_token and account_id property of the account to Plaid via the /processor/token/create endpoint in order to create a Knot processor_token. You'll send this token to Knot and they will use it to securely retrieve transaction data from Plaid.

You can create Knot processor_tokens in both API environments:

• Sandbox (https://sandbox.plaid.com): test simulated users
• Production (https://production.plaid.com): production environment for when you're ready to go live and have valid Knot Production credentials

1const {
2  Configuration,
3  PlaidApi,
4  PlaidEnvironments,
5  ProcessorTokenCreateRequest,
6} = require('plaid');
7
8// Change sandbox to production when you're ready to go live!
9const configuration = new Configuration({
10  basePath: PlaidEnvironments[process.env.PLAID_ENV],
11  baseOptions: {
12    headers: {
13      'PLAID-CLIENT-ID': process.env.PLAID_CLIENT_ID,
14      'PLAID-SECRET': process.env.PLAID_SECRET,
15      'Plaid-Version': '2020-09-14',
16    },
17  },
18});
19
20const plaidClient = new PlaidApi(configuration);
21
22try {
23  // Exchange the public_token from Plaid Link for an access token.
24  const tokenResponse = await plaidClient.itemPublicTokenExchange({
25    public_token: publicToken,
26  });
27  const accessToken = tokenResponse.data.access_token;
28
29  // Create a processor token for a specific account id.
30  const request: ProcessorTokenCreateRequest = {
31    access_token: accessToken,
32    account_id: accountID,
33    processor: 'knot',
34  };
35  const processorTokenResponse = await plaidClient.processorTokenCreate(
36    request,
37  );
38  const processorToken = processorTokenResponse.data.processor_token;
39} catch (error) {
40  // handle error
41}

For a valid request, the API will return a JSON response similar to:

1{
2  "processor_token": "processor-sandbox-0asd1-a92nc",
3  "request_id": "m8MDnv9okwxFNBV"
4}

For possible error codes, see the full listing of Plaid error codes.

To test the integration in Sandbox mode, simply use the Plaid Sandbox credentials along when launching Link with a link_token created in the Sandbox environment.

Your account is immediately enabled for our Sandbox environment (https://sandbox.plaid.com). To move to Production, please request access from the Dashboard. You will need Knot Production credentials prior to initiating live traffic in the Knot API with Plaid.

Find answers to many common integration questions and concerns—such as pricing, sandbox and test mode usage, and more, in our docs.

If you're still stuck, open a support ticket with information describing the issue that you're experiencing and we'll get back to you as soon as we can.