We have created Sandbox Finance which is a mock-up bank you can use to test Account Information product.
We suggest you follow the Quickstart Guide for integration. Below are the guidelines on how to use Sandbox Finance in that process.
There are two steps when one has to provide a unique identifier for an financial institution: creating an end user agreement and building a Link.
In those two steps, whenever you need to provide an institution_id, provide SANDBOXFINANCE_SFIN0000 as a value. When the end user accesses the link, it will start a connection with Sandbox Finance.
The end users can provide any input value for user id and code generator fields in the Sandbox Finance authentication page to continue the journey.
When the end user authenticates with Sandbox Finance, you can query results similar to any real connection.