Initialize Plaid Items

Before getting a Signal Transaction Score for a proposed transaction, your end users need to link a bank account to your app using Link, Plaid's client-side widget. Link will connect the user's bank account and obtain the consent required to perform this evaluation.

See the Link documentation for more details on setting up a Plaid Link session. At a high level, the steps are:

1. Call /link/token/create.

   • Put signal and auth in the products array, along with any other Plaid products (except Balance) you will be requiring, e.g. products: [signal, auth].
   • Put any other Plaid products you plan to use in the optional_products or required_if_supported_products arrays, e.g. required_if_supported_products: [identity].

2. Initialize Link using the link_token created in the previous step. For more details for your specific platform, see the Link documentation. The user will now go through the Link flow.

3. Call /item/public_token/exchange to exchange the public_token for an access_token.

4. Obtain the account_id of the account used for the transaction you wish to perform the evaluation on; this can be obtained from the metadata.accounts field in the onSuccess callback, or by calling /accounts/get or /link/token/get.

Once you have your Plaid Item, continue to evaluate the risk of the transaction.

You may have Items that were not initialized with signal; for example, if you are adding Signal support to an existing Plaid integration. In this case, for best results, call /signal/prepare on the Item before your first call to /signal/evaluate. If you skip calling /signal/prepare, the Item's first call to /signal/evaluate will take longer and be less accurate, because Plaid will not have had the opportunity to pre-load certain data about the Item. Subsequent calls to /signal/evaluate on the Item will have higher accuracy.

If you intend to add Signal to an existing Item, and the user has not already agreed to the risk product disclosure in Link, you will receive the ADDITIONAL_CONSENT_REQUIRED error when calling /signal/evaluate. As of June 2026, the user must agree to this disclosure before you can call /signal/evaluate, even if you have not enabled Data Transparency Messaging. To resolve this error, send the Item through update mode, making sure to include signal in the additional_consented_products field when calling /link/token/create.

The risk product disclosure will automatically be presented in the Link flow if signal is included in any of the products arrays, including products, additional_consented_products, optional_products, or required_if_supported_products, in the /link/token/create call used to create the Link token.

If you have a large number of existing Items that require update mode for this reason, contact your Plaid account manager for more details and assistance.