Use Link to connect to your users' financial accounts with the Plaid API
Introduction to Link
Plaid Link is the client-side component that your users will interact with in order to link their accounts to Plaid and allow you to access their accounts via the Plaid API.
Plaid Link will handle credential validation, multi-factor authentication, and error handling for each institution that we support. Link works across all modern browsers and platforms, including web, iOS, Android, as well as via React Native and mobile webviews.
Link flow overview
The diagram below shows a model of how Link is used to obtain a
public_token, which can then be exchanged for an
access_token, which is used to authenticate requests to the Plaid API.
/link/token/createto create a
link_tokenand pass the temporary token to your app's client.
link_tokento open Link for your user. In the
onSuccesscallback, Link will provide a temporary
/item/public_token/exchangeto exchange the
public_tokenfor a permanent
item_idfor the new
access_tokenand use it to make product requests for your user's
In code, this flow is initiated by creating a
link_token and using it to initialize Link. The
link_token can be configured with the Plaid products you will be using and the countries you will
need to support. Once the user has logged in via Link, Link will issue a callback containing a
public_token, which can be exchanged for an
Link is initialized by passing the
link_token to Link. The exact implementation details for passing the
link_token will vary by platform. For detailed instructions, see the page for your specific platform: web, iOS, Android, React Native or mobile webview.
Some institutions use an OAuth authentication flow, in which Plaid Link redirects the end user to their bank's website or mobile app to authenticate. Plaid now recommends that all developers integrate OAuth support into their apps. To learn how to connect to an institution that uses OAuth, see the OAuth guide.
You can customize parts of Link's flow, including some text elements, the institution select view, and the background color, and enable additional features like the Account Select view straight from the Dashboard. You can preview your changes in realtime and then publish them instantly once you're ready to go live. For more details, see Link customization.
To help you take advantage of the options available for customizing and configuring Link, Plaid offers a best practices guide with recommendations for how to initialize and configure Link within your app.
Link's appearance will also automatically change if the institution selected is not in a healthy state. For more details, see Institution status in Link.
Returning user flows
The returning user flow allows you to enable a faster Plaid Link experience for your users who already use Plaid. To learn more, see Returning user experience.
If your application will access an Item on a recurring basis, rather than just once, it should support update mode. Update mode allows you to fix an Item if it goes into an error state, such as when a user changes their password or MFA information. For more information, see Updating an Item.
It's also recommended to have special handling for when a user tries to link the same Item twice. Linking duplicate Items can lead to higher bills and end-user confusion. To learn more, see preventing duplicate Items.
Occasionally, Link itself can enter an error state if the user takes over 30 minutes to complete the Link process. For information on handling this flow, see Handling invalid Link tokens.
Link token migration
Prior to July 2020, Link was initialized using a public key instead of a
link_token. If you are an existing Plaid developer using a Plaid public key, it is recommended that you migrate to a
link_token-based implementation as soon as possible, using the instructions in the Link token migration guide. For those who are not yet ready to migrate, instructions on maintaining a legacy integration can be found in the legacy integration guide.
Account Select v2 migration
In September 2021, Plaid introduced an update to the Account Select pane (Account Select v2). When using Account Select v2, if a user links an Item at an institution where they hold multiple accounts, you will only receive data from the specific account(s) the user has selected to share with you. Migration to Account Select v2 is required; any Plaid integrations still using Account Select v1 will be automatically migrated beginning in March 2022. To learn more, see the Account Select v2 migration guide.
Since all your users will go through Link, it's important to build as robust an integration as possible. For details on dealing with common problems, see the Troubleshooting section.